Embed Size (px)
Citation preview
Volume 28 Issue 4 Article 9
2020
Improved food additive analysis by ever-increasing Improved food additive analysis by ever-increasing
nanotechnology nanotechnology
Follow this and additional works at: https://www.jfda-online.com/journal
Part of the Food Science Commons, Medicinal Chemistry and Pharmaceutics Commons,
Pharmacology Commons, and the Toxicology Commons
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative
Works 4.0 License.
Recommended Citation Recommended Citation Zhang, Jing; Hu, Shui; Du, Yi; Cao, Ding; Wang, Guirong; and Yuan, Zhiqin (2020) "Improved food additive analysis by ever-increasing nanotechnology," Journal of Food and Drug Analysis: Vol. 28 : Iss. 4 , Article 9. Available at: https://doi.org/10.38212/2224-6614.1152
This Review Article is brought to you for free and open access by Journal of Food and Drug Analysis. It has been accepted for inclusion in Journal of Food and Drug Analysis by an authorized editor of Journal of Food and Drug Analysis.
Improved food additive analysis by ever-increasing nanotechnology Improved food additive analysis by ever-increasing nanotechnology
Cover Page Footnote Cover Page Footnote Jing Zhang and Shui Hu contributed equally to this work.
This review article is available in Journal of Food and Drug Analysis: https://www.jfda-online.com/journal/vol28/iss4/9
Improved food additive analysis byever-increasing nanotechnology
Jing Zhang a,1, Shui Hu a,1, Yi Du b, Ding Cao a, Guirong Wang a, Zhiqin Yuan a,b,*
a State Key Laboratory of Chemical Resource Engineering, College of Chemistry, College of Material Science and Engineering, BeijingUniversity of Chemical Technology, Beijing 100029, Chinab Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), TsinghuaUniversity, Beijing 100084, China
Abstract
Improper use of food additives may lead to potential threat to human health, making it important to develop sensitiveand selective method for their detection. Nanomaterials with unique chemical and electrochemical properties showextensive applications in the design of food additive sensing systems. In this review, we summarize the recently adoptedelectrochemical and optical analysis of food additives based on nanomaterials. Detection of typical food additives(colorants and preservatives) by using different sensing mechanisms and strategies are provided. In addition, deter-mination of illegal food additives is also briefly introduced. Finally, this review highlights the challenges and futuretrend of nanomaterial-based food analysis system.
Keywords: Nanomaterials, Food colorants, Food preservatives, Illegal additives, Detection
1. Introduction
A s the changing population and lifestyle,there are increasing requirements on food
quality and texture. To enhance the appearance,fragrance, taste, or storage of food, additional in-gredients, usually called as food additives, aregenerally applied in food industry. According totheir functions, these food additives can be clas-sified into different species, including colorants,preservatives, sweeteners, thickeners, emulsifiers,raising agents, and acidity regulators, etc [1].Reasonable use of these food additives not onlyimproves the color and taste of food, but alsoboosts the nutritional value. Unfortunately,improper use of some food additives leads to apotential threat to human life and health [2,3]. Inaddition, some food additives have been demon-strated as potential disease triggers. For example,
Lakshmi et al. found that indigo carmine colorantmay cause permanent damage to the cornea andconjunctiva [4]. Ma et al. also reported thatexcessive intake of indigo carmine has mutageniceffects and may lead to tumors [5]. Furthermore,some synthetic chemicals with high toxicitieshave also been used as illegal food additives,which cause serious food accidents. Therefore,the development of simple and effective methodto monitor the content of food additives isextremely important for protecting Humanbeings.To accomplish successful detection of food addi-
tives, many methods based on liquid chromatog-raphy, mass spectrometry, and electrochemistryhave been reported [6e12]. For instance, Harp et al.reported the determination of seven certified col-orants using liquid chromatography [13]. In com-parison with sole liquid chromatography technique,the combination of liquid chromatography and
Received 29 May 2020; revised 17 August 2020; accepted 1 September 2020.Available online 1 December 2020
* Corresponding author at: State Key Laboratory of Chemical Resource Engineering, College of Chemistry, College of Material Science and Engineering,Beijing University of Chemical Technology, Beijing 100029, China. Fax: þ86 10 64411957.E-mail address: [email protected] (Z. Yuan).
1 These authors contributed equally to this work.
https://doi.org/10.38212/2224-6614.11522224-6614/© 2020 Taiwan Food and Drug Administration. This is an open access article under the CC-BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
REVIEW
ARTIC
LE
mass spectrometry provides higher sensitivity to-ward food additive analysis. Using this couplingtechnique, Hao et al. has proposed a sensitive andselective method for tertiary butylhydroquinone(typical preservative) detection [9]. Despite of theanalysis of food additives using these conventionaldetection techniques, there are still some draw-backs, including complicated sample preparation,complicated analytical steps, and time-consumingtesting. In addition, the sensitivities of some systemsdo not suffice the demand of food quality evalua-tion. And thus, the exploration of new systems withsimplicity and high sensitivity for food additive isstill charming.Nanomaterials with large specific surface area and
unique chemical/electrochemical properties arewidely used as sensing probes, nanocatalysts,nanodrugs, and so on [14e20]. In last two decades,profiting from the ever-increasing nanoscience andnanotechnology, a number of facile and sensitivedetection techniques toward food additives havebeen developed [21e23]. A brief summary ofnanomaterial-based detection systems toward foodadditives would benefit the researchers to chooseproper method in the future work. In this review, weessentially focus on recent advances in food additiveanalysis using nanomaterials that have been re-ported since 2016. Detection of two kinds of exten-sively used food additives, including colorants andpreservatives, is discussed. In addition, the analysisof illegal food additives based on nanotechnology isalso introduced. Finally, challenges and future out-looks of nanomaterial-based food additive analysisare discussed.
2. Food colorant detection
Food colorants control the aesthetic appearance offood, which makes food more attractive and plays animportant role in the choice of food [24]. Thus, foodcolorants are essential for food manufacturing in-dustry because they can excite the purchase interestof consumers. Many colorful compounds can beused as food colorants, including sunset yellow,allure red, lemon yellow, erythrosine, carmine,amaranth, tartrazine, acid orange, and so on [25e36].In general, natural food colorants are harmless oreven beneficial to the human body. Through thegenotoxicity evaluation, Hobbs et al. found thatgardenia blue as natural food colorant does not posegenotoxic concern [37]. Nevertheless, the high cost ofnatural colorants leads to the wide circulation ofmany bright colored synthetic chemicals with highstability and low cost. These synthetic colorants areusually organic reagents prepared by artificial
chemical synthesis. They are mainly used in thecoloring of carbonated drinks, fruit juice drinks,confectionery wine, confectionery, candy, hawthornproducts, pickled vegetables, ice cream, jelly, choc-olate, cream, instant coffee, and other foods. How-ever, it should be noticed that many food colorants(especially synthetic food colorants) are suspected ofcarcinogenesis and have been strictly limited in use.To avoid food colorant contamination, a fewmethods have been reported by using nano-maeterials as signal reporters [38,39]. In view of theusage of these food colorants, analysis of them in softdrinks and other foods are concluded.
2.1. Colorants analysis in soft drinks
Soft drink is defined as the natural or artificialbeverage with low alcohol content (<0.5%, massratio). In addition to the high cost, natural colorantsare easy to change color or fade in the processing ofsoft drinks. Therefore, water-soluble synthetic col-orants are usually used to improve the sensoryquality of soft drinks, which increases the buyer'spreference. The common soft drinks includecarbonated drinks, juice drinks, vegetable juicedrinks, tea drinks and bottled drinking water drinks,and so on. In order to achieve rapid and sensitivedetection of artificial colorants in soft drinks, nano-materials have been widely used as accumulators oroptical reporters. For example, Bakheet et al. re-ported a fluorimetric Allura red detection system insoft drinks by using poly(ionic liquid) immobilizedmagnetic nanoparticles as the adsorbent [40]. In thisreport, the author adopted magnetic solid phaseextraction technology, which greatly shortened theanalysis time. Compared with conventional solid-phase extraction fillers, this method only requiressmall amount of adsorbent and short equilibriumtime to achieve low-concentration micro-extraction.Such high extraction capacity and extraction effi-ciency are majorly due to the large specific surfacearea and short diffusion distance of nanoparticles.Because of the good stability and hydrophobicity ofpolyionic liquids, the authors used free radicalcopolymerization to fix polyionic liquids (PILs) onthe surface of magnetic nanoparticles (Fe3O4@SiO2)to obtain adsorbents (Fe3O4@SiO2@PILs). Moreover,Allura red can be firmly adsorbed on the PIL bypep hydrophobic dispersion and weak dipoleinteraction mechanism because of the azo and aro-matic structures, which greatly improves the sepa-ration rate. Finally, magnetic solid phase extractionwas combined with fluorescence spectrophotom-etry, they successfully achieved Allura red analysisunder the optimized conditions, with a limit of
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 623
REVIEW
ARTIC
LE
detection (LOD) of 0.002 mg/mL. And good linearitywas observed in concentration range from 0.01 to0.50 mg/mL. Additionally, the proposed methodcould be applied for Allura red analysis in candiesand beverages samples with acceptable deviations.The same is the principle of extraction. SwapnilTiwari et al. in order to detect tartrazine in softdrinks, the silver nanoparticles were modified withhydrophobic ligands, and then the tartrazine wasextracted by single drop microextraction. Finally,the satisfactory results were obtained by combiningwith diffusion reflection Fourier transform infraredspectroscopy [41].As can be seen from the above reports, combining
the excellent surface adsorption activity of nano-particles with traditional detection methods iscurrently an effective method for detecting foodcolorants in soft drinks. Among the traditionaldetection methods, the electrochemical method hasbeen widely used due to its portability, high sensi-tivity, low cost and short analysis time [42e46]. Inthis detection method, the glassy carbon electrode(GCE) has become a popular working electrode byvirtue of its good conductivity and high chemicalstability. As a kind of chemically modified electrode,it will be more and more popular to modify glassycarbon electrode with nanomaterials to improve itselectrochemical performance. When choosing thematerials to modify the GCE, carbon nanotubes haveunique physical and chemical properties, which canpromote the electron transfer of electroactive sub-stances, and show better selectivity and moreobvious electrocatalysis for the target compounds.Among the carbon nanotubes, multi-walled carbonnanotubes (MWCNTs) have outstanding tensilestrength, excellent electrical conductivity, highchemical stability, and can produce good electrontransfer rate. Compared with the bare electrode,their films have considerable surface enhancementeffect, which can significantly improve the sensitivityof the sensor. For example, P. Sierra-Rosales et al.used 1,3-dioxolane as the dispersant and modifiedthe glassy carbon electrode with MWCNTs to obtainan electrochemical sensor with high stability andgood repeatability. It showed high sensitivity andreproducibility in the detection of tartrazine, sunsetyellow and carmoisine in soft drinks [29]. After sur-face functionalization of MWCNTs modified elec-trode with molecularly imprinted polymer throughthe electropolymerization of acrylamide in thepresence of sunset yellow template, Arvand et al.developed a selective electrochemical method forsunset yellow [47]. The good specificity is attributedto the molecular recognition of molecularly imprin-ted polymer, which rules out the interference of
other chemicals. With the proposed electrochemicalsystem, they realized sunset yellow sensing in theconcentration range from 0.05 to 100 mM, with a LODof 5.0 nM. Polydopamine with good electron transfercapability has been widely used as the surfacecoating material for electrodes. Using dopamine asthe monomer, Yin et al. reported the surface func-tionalization of MWCNTs modified electrode withpolydopamine (molecularly imprinted polymer) inthe presence of sunset yellow template [48]. Themodified electrode is capable of sunset yellowsensing with excellent specificity because of thehighly matched imprinted cavities, as shown inFig. 1. Surface coating of polydopamine not onlyenhances the capture of sunset yellow, but alsopromotes the electron transfer, which leads to highsensitivity. Using this electrode, electrochemicaldetection of sunset yellow was achieved in the con-centration range of 2.2 nMe4.64 mM, with a LOD of1.4 nM (S/N¼ 3). This LOD is much lower than mostpreviously reported works. The prepared sensor wassuccessfully used to detect sunset yellow in realspiked samples. The combination of MWCNTs withgold nanoparticles (AuNPs) is an attractive materialwith a wide size range and size dependent optical,magnetic, electronic and chemical properties. Chi-tosan (CHIT) has good adhesion, high mechanicalstrength, excellent film-forming ability and non-toxic, and is easy to be chemically modified becauseof its rich amino groups. Rovina et al. Modified GCEwith graphene (GO), MWCNTs and AuNPs viaCHIT to obtain the electrode (CHIT/GO/MWCNTs/AuNPs/GCE) [49]. The electrode was applied to thedetermination of sunset yellow in soft drinks in theconcentration range of 10e90 mg/mL, LOD of0.032 mg/mL, showing excellent sensitivity.In addition to MWCNTs, other nanomaterials
(bimetallic nanoparticles, transition metal oxides,graphene oxide, etc.) can also be used as goodcandidates for electrode modification and electro-chemical activity enhancement [27,30,36,50]. Forexample, in order to detect amaranth in soft drinks,Wang et al. prepared a porous graphene material-graphene nanomesh (GNM) to modify the glassycarbon electrode (GCE) to obtain GNM/GCE elec-trode [27]. In addition, in order to prove that thisporous nanomaterial modified electrode has higherelectrochemical performance, the author comparedit with reduced graphene oxide (RGO) modifiedglassy carbon electrode (RGO/GCE) and bareglassy carbon electrode (GCE). Because the intro-duction of macroporous density into graphenesheet is not only conducive to the adsorption ofamaranth growth molecules to the working elec-trode surface through the pores, but also conducive
624 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
to the rapid diffusion of electrons in the electro-chemical detection process, the electrochemicalactivity of GNM/GCE is significantly higher thanthat of RGO/GCE and bare GCE. In addition,Parisa S. Dorraji et al. synthesized a ZnO/cysteicacid nanocomposite to modify the glassy carbonelectrode (GCE) and can be used to simultaneouslydetermine sunset yellow and tartrazine in softdrinks [30]. In this report, Cysteine is formed byelectrochemical oxidation of L-cysteine on the sur-face of glassy carbon electrode (GCE), and is usedas a suitable polymer framework to make ZnOnanofilms uniformly deposited on the electrodesurface. The fabricated modified electrode facili-tated the electron transfer of sunset yellow andtartrazine, resulted in increased oxidation currents.Ding et al. prepared a nano-hybrid of electro-chemically reduced graphene oxide (MnO2 NRs-ERGO) decorated with manganese dioxide nano-rods, which was used to modify the glassy carbonelectrode (GCE) [51]. Because of the strong catalyticactivity of MnO2 NRS and the high adsorption ca-pacity and excellent conductivity of ERGO, the
modified glassy carbon electrode showed excellentanalytical performance such as high sensitivity,high selectivity and low cost. Moreover, it was usedto detect sunset yellow (SY) in soft drinks withwide linear range and low detection limit. Zhao etal. developed a molecularly imprinted copolymersensor (MIP-PMDB/POPD-GCE) by electro-polymerizing m-dihydroxybenzene (m-db) and o-phenylenediamine (o-PD) and then directly fixingthe copolymer on the surface of glass carbonelectrode (GCE) [32]. Due to the fact that thecopolymer is filled with nanopores which can bindtartrazine molecules, tartrazine in soft drinks canbe determined quickly.In addition to glassy carbon electrode, carbon
paste electrode, graphene electrode and metalelectrode can also be used for the detection ofcolorants in soft drinks [26,28,31,35,39,52]. Forexample, Ya et al. simply synthesized a Zinc oxidenanoflower (ZnONF) to modify the carbon pasteelectrode to obtain a zinc oxide nanoflower modi-fied carbon paste electrode (ZnONF/CPE), whichwas used to detect sunset yellow in soft drinks.
Fig. 1. Schematic preparation of MWCNT@polydopamine (PDA) and sunset yellow (SY) sensing. Reprinted with permission from Ref. [48] withpermission from the Elsevier, Copyright 2018.
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 625
REVIEW
ARTIC
LE
Under the best conditions, the detection limit is0.10 mg/L. Due to the large specific surface area andhigh accumulation efficiency of ZnONF, the elec-trochemical oxidation of sunset yellow wasenhanced by ZnONF modified carbon paste elec-trode (ZnONF/CPE) [52]. Wu et al. used one-pothydrothermal to fix the ZnO/RGO/ZnO nano-composite in situ on the zinc foil, and used theobtained ZnO/RGO/ZnO@Zn directly as the elec-trode material to detect sunset yellow in softdrinks, and It shows an ultrahigh sensitivity of20.25 mA mM�1 cm�2, a low LOD (3 nM), a widelinear detection ranging from 0.01 to 5 mM [39]. Bycasting a double-stranded spiral copper (I) onto thesurface of a single-walled carbon nanotube modi-fied screen-printed electrode, Nu~nez-Dallos et al.reported the voltammetry of amaranth red andtartrazine in soft drinks [31]. Using this method,amaranth red and tartrazine can be detected at30 nM and 60 nM (S/N ¼ 3), respectively. Thesmall relative standard deviation (3.5%, n ¼ 7, threedifferent electrodes) proves the high accuracy ofthe proposed method. In addition, the organicmolecule b-cyclodextrin can also be used to modifythe electrode to enhance the electrochemicaldetection in soft drinks due to its good adsorptioncapacity [36,53]. Although the most commonly usedmethod for detecting colorants in soft drinks is tomodify the working electrode with nanotechnology,in recent years, some methods other than electro-chemical sensing have been reported to betterdetect colorants in soft drinks [54e57]. Amongthem, surface enhanced Raman spectroscopy(SERS) as a highly sensitive nanotechnology canalso be used to detect colorants in soft drinks. Forexample, Ou et al. used gold nanorods (Au NRs) asSERS substrates and proposed a system to detectAllure red or sunset yellow in soft drinks [55]. Intheir work, they found that the aspect ratio of goldnanorods is crucial for SERS signals, and thestrongest Raman signal enhancement is achievedby special Au NRs (aspect ratio ¼ 2.4 or 1.8). He etal. chose cysteamine to modify the gold nano-particle SERS substrate, and then detected the acidpigment with weak surface affinity in soft drinks[56]. Because cysteamine has a positively chargedgroup eNH3, it can electrostatically interact withacidic pigments, and hydrogen carbonate bondsbetween the calcium carbonate and the pigmentmolecules, making the pigment molecules closer tothe surface of the gold nanoparticles. Experimentalresults show that the method still has good repro-ducibility under complex conditions, and the re-sults can be detected very quickly and sensitively.
2.2. Colorants analysis in other foods
As food cosmetics, food colorants can also be usedfor other foods, e.g., meat, cake, and candy. It isnoticed that food colorants not only provide attrac-tive color, but also help to preserve water. However,according to food colorants regulations, syntheticcolorants are not able to be used in meat and itsprocessed products. In this case, only few naturalcolorants could be applied in meat processing. Forexample, Carminic acid (CA) is extensively used as atypical red and natural food colorants for meatproducts. However, the allowable concentrationrange of CA in foodstuff is set to be 25e500 mg/kgby the Standardization Administration of China (GB2760-2014). Therefore, in order to detect CA, Yuan etal. learned that small-sized layered double hydrox-ides (LDHs) can increase the intensity of thechemiluminescence (CL) of the Luminol-H2O2 sys-tem by more than 950 times [58]. The enhancedchemiluminescence is due to the synergistic effect ofthe positively charged layer and the intercalatedcarbonate. The former attracts luminol dianions andincreases their local concentration, while the latterforms carbonates and promotes the formation ofemissive 3-aminophthalate anions. Therefore, com-bined with the negative charge nature of CA, theauthor proposed a sensitive chemiluminescencedetection CA method based on the LDH-luminol-H2O2 system (Fig. 2) [59]. The surface adsorption ofCA causes the positively charged center of the LDHlayer to be occupied, which hinders the approach ofthe Luminol dianion. Similarly, the reducing powerof CA inhibits the formation of free radicals, whichreduces the interaction between luminol divalentanions and free radicals. In addition, the UV-visabsorption range of CA overlaps with the chemilu-minescent emission of the luminescent 3-amino-phthalate anion, resulting in the occurrence ofchemiluminescent resonance energy transfer. As aresult, the synergy of occupied active sites, reduc-tion of free radicals and CL resonance energytransfer leads to quenching of CL emission. Basedon this mechanism, they achieved the detection ofCA in dried pork slices within a concentration rangeof 0.5e10 mM, with a LOD of 0.03 mM. They alsostudied the repeatability of the proposed CL sensor.During 11 repeated measurements of 2 mM CA, thecalculated relative standard deviation was 2.9%,which proved the accurate CA analysis of thedesigned system. Indeed, the chemiluminescencespectrophotometry used in this report as a tradi-tional detection method has the advantages of lowbackground noise, fast response and simple instru-ment [60,61], it has been widely used in combination
626 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
with the increasingly developed nanotechnology[58,59,62].Electrochemical methods with high sensitivities
have also been applied for the detection of foodcolorants. For example, Arvand et al. prepared ho-mogeneous bimetallic nickel tin oxide hollownanospheres by template method to modify carbonpaste electrode to obtain a new electrode (NieSn-oxide NSs/CPE) [34]. The results show that theelectrode has higher sensitivity than bare carbonpaste electrode in the detection of erythrosine incommercial food such as candy and jelly. This isbecause the active sites of the reaction are greatlyincreased due to the high specific surface area ofbimetallic hollow nanospheres, and the synergisticaction of the two metals can make the electrontransfer in NieSn-oxide NSs easier. However, thespecific mechanism of the electrode for the detec-tion of erythrosine in the article needs further study.Zhao et al. used molecular imprinting technology forelectrochemical sensing to specifically detect thefood pigment erythrosine [33]. In order to improvethe sensitivity and stability of the reduced grapheneoxide on the surface of the glassy carbon electrode,the author used sodium citrate as a reducing agentand stabilizer, using 2-aminoethanol (2-AET) func-tionalized, uniformly distributed gold nanoparticles(AuNPs) modified reduced graphene oxide (RGO);in order to improve the selectivity of the sensor, theauthor used erythrosine as template molecules toobtain molecularly imprinted cavities on the modi-fied electrode surface. Using this method to detectfood coloring shows high selectivity and sensitivity.Pogacean et al. prepared the nanocomposites bymixing graphene oxide with TiO2eAg nano-particles, and then used it to modify the gold
electrode to detect amaranth also showed goodsensitivity [25]. In addition, chitosan as an easilymodified organic molecule can also be used tomodify glassy carbon electrodes to better detectfood colorants [63].Although research on how to develop new nano-
materials to modify working electrodes (glass car-bon electrodes, carbon paste electrodes, grapheneelectrodes, metal electrodes, etc.) is currently themost popular direction for the detection of softdrinks and food colorants other than soft drinks,SERS also occupies a proper place in the detectionof food colorants due to its fast, sensitive and non-destructive testing characteristics [64,65]. In com-parison with ordinary Raman systems, the signals ofRaman reporter on the surface of nanoparticles canbe greatly enhanced through the surface plasmonresonance-induced electromagnetic enhancementand/or charge transfer mediated chemicalenhancement [66,67]. To apply SERS technique intothe detection of food colorants, the key issue is toobtain a substrate with high SERS activity. Gener-ally speaking, since the random distribution of hotspots on the SERS substrate will cause the SERSsignal to show poor repeatability, it is necessary tofabricate nanostructures with uniform gaps. Wu etal. prepared gold nanoparticles with a diameter of80 nm into a single layer of uniform gold nano-particle film by solvent driven self-assembly [68].Using this film as a SERS substrate, the sensitiveanalysis of sunset yellow and tartrazine in ppm levelwas realized. In addition, the author also used it todetect illegal food additives including ciprofloxacin,diethylhexyl phthalate and azodicarbonamide. Wuet al. used ascorbic acid to reduce silver nitrate, inthe presence of a polyvinylpyrrolidone (PVP)
Fig. 2. Schematic representation of the sensing principle of LDH-luminol-H2O2 system for the detection of CA. Reproduced from Ref. [59] withpermission from The American Chemical Society, Copyright 2018.
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 627
REVIEW
ARTIC
LE
surfactant, regulates the generation of uniformflower-like silver nanoparticles for SERS substrateanalysis to detect carmine in food additives [69].Using the same method to produce uniformflower-shaped silver nanoparticles, Ai et al. usedthis silver nanoparticles as a SERS substrate tostudy four food colorants (food blue, tartrazine,sunset yellow and acid red) [70]. Experimental re-sults show that the LOD of the four colorants is aslow as 100 nM (of which tartrazine's LOD is close to10 nM). This shows a very high sensitivity for thedetection of international standard food coloring.However, not all target analytes can be detectedsimply by using metal nanoparticles as the sub-strate, because metal nanoparticles have weakadsorption to some analyte molecules, making itdifficult for analyte molecules to access metalnanoparticles [71]. In addition, silver nanoparticleshave a tendency to oxidize, so it is difficult to be along-term SERS substrate [72]. Therefore, when wechoose the SERS method to detect food additivesor other target analytes, we should take into ac-count the characteristics of the target molecule,and if necessary, modify the nano-substrate toimprove its adsorption [73]. In the past four years,most of the relevant reports have used electro-chemical methods or SERS. I think this must beinseparable from the word “adsorption”. Toimprove the traditional detection methods withnanotechnology is to make full use of the highspecific surface area of nanoparticles to increasethe adsorption of target molecules, so as toimprove the sensitivity of traditional methods. Thisis the case with electrode modification, the selec-tion of suitable SERS substrate, even the traditionalhigh performance liquid chromatography (HPLC)[74]. Partial detection methods for food colorantswere summarized in Table 1.
3. Food preservative detection
Food contains lots of organic compounds, and itstime-dependent spoilage is inevitable. Putrescentfoods are extremely toxic to Human health andeven cause death. Thus, the storage of food is oneof the key issues in food industry. Based on thespoilage process, food spoilage primary includestwo pathways: contamination by microorganismand oxidation-induced degradation. To extend thefood storage period, some chemical compoundsare added as ingredients, called as food pre-servatives [75]. According the function mechanism,these food preservatives can be generally dividedtwo classes, antimicrobial and antioxidant. Anti-microbial preserves food by inhibiting or killing
Table1.
Summaryof
detectionmetho
dstowardfood
colorants.
#Material
Strategy
Targe
tan
alytes
Linea
rrange
(mM)
LOD
(mM)
Ref.
1grap
hen
enan
omeshes/G
CE
electroa
nalysis
amaran
th5.0�
10�3 e
1.0
7.0�
10�4
[27]
2poly(p-aminob
enzenesulfon
icacid)/zincox
idenan
oparticles/C
PE
electroa
nalysis
tartrazine
0.0349e5.44
0.08
[28]
3ZnO/cysteic
acid
nan
ocom
posite/GCE
electroa
nalysis
sunsetye
llow
0.1e
3.0
0.03
[30]
tartrazine
0.07
e1.86
0.01
4MIP-PmDB/PoP
D-G
CE
electroa
nalysis
tartrazine
5.0�
10�3 e
1.1
3.5�
10�3
[32]
5grap
hen
ewith2-am
inoe
than
ethiolfunctionalized
gold
nan
oparticles
electroa
nalysis
erythrosine
3.75
�10
�2 e
150
4.77
�10
�3
[33]
6nicke
l-tinox
idehollow
nan
ospheres/C
PE
electroa
nalysis
erythrosine
0.1e
100
2.1�
10�3
[34]
7PEDOT:PSS
/AuNPs/CA/SPCE
electroa
nalysis
carm
ine
9.0�
10�3 e
3.9
6.05
�10
�3
[35]
8three-dim
ension
alb-cyclodex
trin
functionalized
grap
hen
eae
roge
ls/G
CE
electroa
nalysis
Pon
ceau
4R0.001e
1.0
3.0�
10�4
[36]
9ZnO/R
GO/Z
nO
foil
electroa
nalysis
sunsetye
llow
0.05e5
3�
10�3
[39]
10MIP/f-M
WCNTs/GCE
electroa
nalysis
sunsetye
llow
0.05e10
00.005
[47]
11molecularlyim
printedpolyd
opam
ine-co
ated
multi-walled
carbon
nan
otube
s/GCE
electroa
nalysis
sunsetye
llow
2.2�
10�3 e
4.64
1.4�
10�3
[48]
12electroc
hem
ically-red
ucedgrap
hen
eox
idenan
oshee
tsdecorated
withMnO
2nan
orod
s–GCE
electroa
nalysis
sunsetye
llow
0.01
e2
0.002
[51]
2e10
10e10
013
positivelych
arge
dAuNPs-em
bedded
MIH
sSE
RS
new
red
1.64
e16
40.164
[57]
14laye
rdou
bled
hyd
roxide�
luminol�H
2O2system
chem
iluminescence
carm
ineacid
0.5e
100.03
[59]
15flow
er-shap
edAgNPs
SERS
carm
ine
0.01
e10
000.01
[69]
628 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
bacteria/fungus through the denaturation of micro-bial protein, destruction of cell wall, suppression ofenzymatic activity, etc. Many organic and inorganicchemicals can be used as food antimicrobial,including potassium sorbate, sodium benzoate, ni-trite, and sulfite, etc [18]. While antioxidant protectsfood by hindering the oxidation of certain constitu-ents, e.g., fats. Chemicals with good reducing abilityare applied as antioxidants, such as butylatedhydroxyanisol, butylated hydroxytoluene, tertiarybutylhydroquinone, ascorbic acid, polyphenols [75].Notice that the added food preservatives must benontoxic, thus the contents need to be strictlylimited based on food safety rules. Recent studiesindicated that the excess uptake of food pre-servatives leads to various diseases and even cancer[76e79]. Mohammadzadeh-Aghdash et al. summa-rized the interaction between food preservativesand serum albumin and revealed that the interac-tion leads to the activation of inflammatory pathsand acceleration of diabetes [80]. Taking this intoconsideration, the development of sensitive detec-tion methods toward food preservatives is of sig-nificance to ensure food safety and Human health.In this section, detection methods on antimicrobialand antioxidant were briefly introduced.
3.1. Antimicrobial
Similar to the colorant's detection, electrochemicaland optical detection methods are also applicable tofood preservatives analysis. And the detectionsensitivity and selectivity could be improved withthe introduction of nanomaterials. Gold workingelectrode functionalized with p-amino thiophenoland Au NPs has been applied to the electrochemical
detection of nitrite, a typical inorganic food preser-vative [81]. After processing of electrode, nitriteoxidation on the electrode surface with a charac-teristic peak potential of 0.76 V was observed. Andthe current was found to be proportional to the ni-trite concentration. With this system, nitrite detec-tion showed good linearity in concentration range of0.5e50 mg/mL nitrite and a LOD of 0.12 mg/mL.Beyond electrochemical activity, nitrite has somespecial reactivity toward some oxidant. It is wellknown that it can react with hydrogen peroxide andproduces generate peroxynitrous acid under acidicconditions. The highly reactive peroxynitrous acidcan oxidize surface protecting agent, and cause ag-gregation of nanomaterials. Using this tactic, Yuan etal. reported a fluorescence turn-off method to detectnitrite with hyperbranched polyethyleneimine pro-tected silver nanoclusters (hPEI-Ag NCs) [82]. Thesensing was performed under acidic condition inthe presence of excess hydrogen peroxide. Thesurface coating with hyperbranched poly-ethyleneimine is critical to accomplish the sensingapplication. That is because the hyperbranchedmolecular structure endows high stability of Ag NCstoward hydrogen peroxide or sole nitrite. However,the generated peroxynitrous acid destroys thehyperbranched polyethyleneimine and leads to theformation of Ag NC aggregates, which subsequentlycauses the fluorescence quenching (Fig. 3). Based onthis system, nitrite detection was achieved with aLOD of 100 nM, which is much lower thanmaximum contamination level in drinking water setby the U.S. Environmental Protection Agency. Inaddition, this method utilizes a specific reaction, andother anions including F�, Cl�, Br�, I�, C6H5CO
�2 ,
SCN�, N�3 , IO
�3 , IO
�4 , BrO
�3 , ClO
�4 , citrite
3�, EDTA2�,
Fig. 3. Schematic illustration of nitrite induced aggregation of hyperbranched polyethyleneimine protected silver nanoclusters (hPEI-Ag NCs) andfluorescence quenching. Reproduced from Ref. [82] with permission from The Royal Society of Chemistry, Copyright 2016.
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 629
REVIEW
ARTIC
LE
NO�3 , SO2�
3 and SO2�4 , didn't show any visible
interference. The good recoveries and small relativestandard deviation values proved the practicalapplication of the proposed platform for nitriteanalysis in lake water, tap water and seawatersamples.Sulfite has also been widely used as the antimi-
crobial, which can inhibit the enzymatic activity ofsome microorganisms. Using methyl green attachedEu, Sm, Mn-doped CaS nanoparticles, Wang et al.reported a sensitive sulfite detection platform basedon recovery of upconversion luminescence [83]. Thesensing mechanism was shown in Fig. 4, methylgreen quenched the luminescence of CaS nano-particles through fluorescence resonance energytransfer (FRET) mechanism. Introduction of sulfitedestroys the molecular structure of methyl greenand breaks up FRET process, leading to theenhancement of luminescence. With the use ofportable luminescence reader, they achieved sensi-tive sulfite sensing with a LOD of 2 ng/mL, which islower than that with commercial test strips (0.05 mg/mL). Using nitrobenzofurazan response motifanchored structurally asymmetric naphthorhod-amine as the probe; Jin et al. realized fluorimetricsulfite detection in water and wine samples [84].With the integration of the nucleophilicity of sulfiteand the electrostatic attraction mediated reactionkinetics, selective sulfite analysis was achieved witha LOD of 70 nM. In addition, this probe was appliedfor imaging intracellular and endogenous sulfite.
3.2. Antioxidant
There are tens to hundreds of antioxidants, whichcan be used as food preservative. Based on theirsources, they can be divided into natural, syntheticand biological antioxidants. Most of them arephenol compounds. Utilizing chemical/electro-chemical redox reaction, many works have beenreported for the detection of various antioxidants[77,85e89]. For example, using hyperbranchedhPEI-Ag NCs as the signal reporters, Yuan et al.achieved tea polyphenol (natural antioxidant) wasdetected based CL technique [62]. The sensingmechanism is that hydroxyl radicals oxidized AgNCs and induce the emission of CL signal (Fig. 5).However, the hydroxyl radicals could be effectivelyscavenged by tea polyphenols. As a result, the CLintensity decreased. The decreased CL intensity wasproportional to the concentration of tea poly-phenols. With this method, they realized lineardetermination of tea polyphenols in the concentra-tion range of 2.52e76.2 mM. In addition, practicalapplication of the proposed system was verified by
detecting tea polyphenols content in three teasamples (green tea, black tea and oolong tea). Ac-cording to the results, the highest content of teapolyphenols was detected in green tea.Based on electrochemical strategy, Sandeep et al.
also reported the detection of polyphenols (catechol)using graphene nanoribbons/AgNPs/polyphenoloxidase composite modified graphite (Gr) electrode[90]. In this report, polyphenol oxidase (PPO) orcatechol oxidase is a copper-containing oxidore-ductase enzyme that can catalyze the oxidation ofcatechol to the corresponding o-quinone. If anenzyme is to be used to modify the electrode, thekey is to choose a suitable substrate to fix theenzyme on the electrode without changing theactive site of the enzyme. The author chose gra-phene nanoribbons (GNRs) as the matrix becauseGNRs have more open-ended structures than gra-phene and carbon nanotubes, which provide themhigh density of reaction edges and large activesurface area that helps to bind enzyme via electro-static or pep interaction. In addition, because silvernanoparticles are often used as modifiers for bio-sensors due to their high quantum electron transferand catalytic properties, and the capping residueson their surface can effectively clamp GNR and PPOenzymes, retaining all the properties of the enzyme,the author chose AgNPs to modify the matrix tofurther improve the sensitivity and conductivity ofGNR. The Gr/GNRs/AgNPs/PPO sensor obtainedby modifying the graphite electrode with thismethod has a lower detection limit (0.03 mM) and awider linear range (2e2300 mM) for detecting cate-chol. Ascorbic acid is also an efficient natural anti-oxidant, which shows strong reducing ability andcan be used in various areas. The detection ofascorbic acid based on optical techniques has alsobeen reported in last few years. Using metal oxidesor metal hydroxides as the nanocatalysts, colori-metric sensing of ascorbic acid was achieved [91,92].In comparison with natural antioxidants, synthetic
antioxidants usually show stronger toxicity, makingthe detection of these synthetic antioxidantsimportant. Up to now, many electrochemicalmethods toward these synthetic antioxidants havebeen explored with the combination of molecularlyimprinted polymer. Yue et al. reported the rapiddetection of tertiary butylhydroquinone usingPdeAu bimetallic nanoparticles decorated reducedgraphene oxide (rGO) electrode with the surfacefunctionalization of molecularly imprinted polymer[86]. The molecularly imprinted polymer was in-situgenerated with tertiary butylhydroquinone as thetemplate molecule. As expected, selective tertiarybutylhydroquinone detection was achieved by
630 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
integrating electrochemical analysis. For tertiarybutylhydroquinone sensing, the proposed methodprovided the linear range of 0.5e60 mg/mL with aLOD of 0.046 mg/mL. By decorating Au NPs andmolecularly imprinted polymer onto the surface ofthree-dimensional graphite paper electrode, Fan etal. greatly enhanced the detection sensitivity towardtertiary butylhydroquinone [77]. With such a design,tertiary butylhydroquinone was detected in theconcentration range of 80 nMe100 mM, with a LODof 12 nM. The large surface area of three-dimen-sional graphite paper plays an important role on theenhanced sensitivity. Organic electrochemical tran-sistor has also been applied for the electrochemicaldetection of antioxidant. After the modification ofgate electrodes with poly(-diallyldimethylammoniumchloride) and MWNTs,Xiong et al. reported the electrochemical sensing ofgallic acid at very low concentration (10 nM) [93].This system possesses small operating voltage incomparison with traditional electrochemical
methods, and provides a promising tool for portablegallic acid analysis in actual tea beverages.Due to the advantages of small sample volume,
high throughput, and low cost, simultaneousdetection of multiple targets in a single run/volumehave attracted growing attention. For the electro-chemical assays, simultaneous detection of multipleantioxidants is possible with separated voltam-metric peaks. As an example, Ng et al. proposed afast and sensitive method for the simultaneousdetection of tertiary butylhydroquinone, butylhydroxyanisole and butylated hydroxytoluene [94].The voltammetric peaks for tertiary butylhy-droquinone, butyl hydroxyanisole and butylatedhydroxytoluene were observed at 0.278 V, 0.503 V,and 0.747 V, respectively. This method allows thedetection of tertiary butylhydroquinone, butylhydroxyanisole and butylated hydroxytoluene at 0.5,0.3, and 0.7 mg/mL. And the analysis of these anti-oxidants in ghee, sunflower oil and salad dressingwas realized.In addition, array-based sensing with the inte-
gration of principal component analysis and hier-archical cluster analysis is also capable of multipletargets analysis [95,96]. With this strategy, Bordbaret al. developed a colorimetric array for dis-tinguishing 20 various food antioxidants [97]. In thiswork, Au NPs and Ag NPs synthesized by sixdifferent reducing and/or capping agents (sodiumborohydride, chitosan, cetyltrimethylammoniumbromide (CTAB), bovine serum albumin (BSA),glucose and polyvinyl pyrrolidone (PVP)) were usedas the sensing elements. Interaction between indi-vidual antioxidant and these elements causes ag-gregation or morphological changes of Au NPs andAg NPs, which generates unique response pattern(Fig. 6). After the acquirement of colorful imagingwith a digital camera, the color information was
Fig. 4. Schematics of upconversion luminescence (UCL) turn-on sulfite detection using methyl green functionalized upconversion nanoparticles(UCNPs). Reprinted from Ref. [83] with permission from the American Chemical Society, Copyright 2018.
Fig. 5. The sensing mechanism is that hydroxyl radicals oxidized AgNCs and induce the emission of CL signal. Reproduced from Ref. [62]with permission from The Royal Society of Chemistry, Copyright 2017.
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 631
REVIEW
ARTIC
LE
analyzed through principal component analysis andhierarchical cluster analysis. All repeated measure-ments were assigned into the same group, indi-cating the successful differentiation of theseantioxidants. Interestingly, Euclidean Norm wasproportional to the antioxidant concentration.Through the calibration, the LODs for gallic acid,caffeic acid, catechin, dopamine, citric acid, butyl-ated hydroxytoluene, and ascorbic acid were
determined to be 4.2, 13, 53, 6.9, 47, 3.5, and 43 nM,respectively. Partial detection methods for foodpreservatives were summarized in Table 2.
4. Illegal food additives detection
In addition to above food additives, some specialchemicals are also used to improve the storage orappearance of food. However, these chemicals,
Fig. 6. Color difference maps of 20 types of antioxidant. Reprinted from Ref. [97] with permission from the Springer, Copyright 2018.
632 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
known as illegal food additives, are strictly limitedbecause of their seriously harm to the public health.And most food safety incidents reported in pastyears are caused by illegally added industrial addi-tives. To control food safety issues, these illegal foodadditives need to be strictly controlled. Therefore,the development of facile approaches for thedetection of these illegal food additives is veryimportant. With the combination of HPLC tech-nique, several works for analyzing illegal food ad-ditives have been reported [98,99]. In this part, threewell-known illegal food additives, including Sudandye, clenbuterol and melamine, are discussed.
4.1. Sudan dyes
Sudan dyes, including Sudan I, Sudan II, SudanIII, Sudan IV, and Sudan black, are a group of oilsoluble dyes, which are commonly used in plastics,rubber and paint. As synthetic dye, Sudan dyespossess bright red color and are very stable incomparison with natural colorants. Thus, they havebeen used for chemical colorant due to advantagesof colorfastness and low price. However, Sudandyes contain azo structure, which is suspected to becarcinogenic to human being. Recently, these Sudandyes are utilized for food colouration by unscrupu-lous merchants. In consideration of their harm toHuman being, Sudan dye as food additives havebeen severely prohibited according to the FoodStandards Agency.To detect Sudan dyes, many works based on
electrochemical and optical sensing techniques hasbeen reported [100e104]. For example, Ye et al. re-ported an electrochemical detection platform for theSudan I sensing by using CuO nanoparticle-deco-rated 3D N-doped porous carbon (CuO/3DNPC)modified GCE electrode [102]. The potential ofSudan I become lower upon when approachingelectrode, which enhances the current. Using thismechanism, they achieved selective Sudan I detec-tion in a linear concentration range from 2.5 to100 mM with between with a LOD of 0.84 mM. Theyalso realized the detection of Sudan I in ketchup andchili sauces.To enhance the detection sensitivity, Mahmoudi-
Moghaddam et al. proposed a screen printed elec-trochemical sensor by using La3þ-doped Co3O4
nanocubes as electrode substrate [100]. The catalyticcharacter of La3þ greatly decreases the oxidationoverpotential of Sudan I and enhances the peakcurrent. With this advantage, Sudan I could bedetected in the range of 0.3e300.0 mM. And the LODtoward Sudan I was calculated to be 0.05 mM. Dur-ing the selectivity investigation, metal ions andTa
ble2.
Summaryof
detectionmetho
dstowardfood
preservativ
es.
#Materials
Strategy
Targe
tan
alytes
Linea
rrange
LOD
Ref.
1MIP/A
uNPs/ex
folia
tedgrap
hitepap
er(EGP)
electroa
nalysis
tertiary
butylhyd
roquinon
e0.08e10
0mM
0.07
mM
[77]
2grap
hen
equan
tum
dots
fluorescence
asco
rbic
acid
1.11e30
0mM
0.32
mM
[79]
3go
ldnan
oparticles/p-aminothiophen
ol/A
uelectroa
nalysis
nitrite
0.5e
50mg/mL
0.12
mg/mL
[81]
4nitrobe
nzo
furazanan
chored
asym
metricnap
hthorhod
amine
fluorescence
sulfite
2e10
0mM
0.07
mM
[84]
5CoS
e 2nan
oparticles
andreduced
grap
hen
eox
ide/SP
CE
electroa
nalysis
propyl
galla
te0.075e
460.15
mM
0.016mM
[85]
6PdAuNPs/ERGO
nan
ocom
posites
electroa
nalysis
tertiary
butylhyd
roquinon
e0.5e
60mg/mL
0.046mg/mL
[86]
7MoS
2/ZnO
heterostructure
photoe
lectroch
emical
propyl
galla
te0.125e
1470
mM
0.012mM
[89]
8grap
hen
enan
oribbo
ns/AgN
Ps/polyp
hen
olox
idase/grap
hite
electroa
nalysis
catech
ol2e
2300
mM
0.03
mM
[90]
9poly(dially
ldim
ethylam
mon
ium
chloride)
andcarbon
nan
omaterials
nan
ocom
posites/A
uelectroa
nalysis
gallicacid
1e10
mM
0.01
mM
[93]
10go
ldan
dsilver
nan
oparticles
colorimetric
alltype
ofan
tiox
idan
tse
4.2nM/53nM
[97]
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 633
REVIEW
ARTIC
LE
small molecules, including Ca2þ, Ni2þ, Mn2þ, Pb2þ,Mg2þ, Cr2þ, Zn2þ, CN�, Br�, Kþ, Liþ, Agþ, SCN�,sucrose, fructose, lactose, glucose, and urea, have nointerference. In addition, Sudan I detection chilipowder, tomato paste, and ketchup sauce have alsobeen achieved. Similarly, using zinc oxide nano-particles (ZnONPs) as the electrode material, Hey-dari et al. displayed the electrochemical Sudan IIIdetection by integrating rotatable central compositedesign and response surface method [101]. With thiscombination, Sudan III detection was achieved inthe linear dynamic ranges of 0.05e1.0 and1.0e15.0 mM, with a LOD of 2.56 nM.Using Ag NPs as the SERS substrate, Zhao et al.
first reported a simple and effective SERS-basedmethod for the detection of Sudan black B [103]. Asshown in Fig. 7, they realized the Sudan black Bsensing at a concentration of 0.05 mg/mL in standardsolutions. Interestingly, 0.1 mg/kg Sudan black B inblack rice extracts was also detected using the pro-posed SERS-based method. From the perspective ofsaving resources, reducing costs and reducingenvironmental pressure, Hu et al. used tire-derivedcarbon dots as fluorescent sensors for sensitivedetection of Sudan dyes [104]. Because the injectionof nitrogen atoms into the carbon dots can lead to achange in the electronic environment and a signifi-cant increase in photoluminescence efficiency, theauthor used ammonium persulfate to oxidize thetire and dope with nitrogen atoms to make theprepared carbon dots have a high quantum yield of23.8%. Because of the internal filtration effect, thecarbon dots obtained after adding Sudan I-IV willhave a significant decrease in fluorescence. Thismethod is used to realize the sensitive detection ofSudan I-IV in chilli powder with the LODs are 0.17,0.21, 0.53 and 0.62 mM for Sudan I, II, III and IV,respectively.
4.2. Clenbuterol
Clenbuterol is a well-known b2-adrenergic re-ceptor agonist, which is used for the cure of chronicpulmonary and bronchial diseases. However,because of its capability to increase the lean meatrate and feed conversion rate of animals, clenbuterolis illegally used as a growth promoter and feed ad-ditive for livestock and poultry. Unfortunately,excessive clenbuterol residue in meat causes serioushealth problems, including cardiovascular diseases,central nervous diseases, and even acute poisoning.As a result, the monitoring of clenbuterol residue inmeat samples is important to Human health. It isthus important to develop sensitive and selectivemethod for clenbuterol sensing.
Toward this goal, a few systems have beenexplored based on electrochemical and opticalresponse [105e109]. For instance, Zhang et al. re-ported an electrochemical sensor for clenbuteroldetection by using polyoxometalate and zirconiumdioxide nanocomposites as electrode material [106].The used electrode material negatively shifts theoxidation potentials of clenbuterol and enhances thepeak current. With this design, they achieved linearclenbuterol detection in the concentration rangefrom 0.1 to 1000 mM, with a LOD of 5.03 nM. Usingpork as the real sample, they realized clenbuterolwith good recoveries (94.4e102.3%).Beyond electrochemical sensing, optical analysis
of clenbuterol has also been reported. Sun et al.proposed a SERS-based approach to detect clenbu-terol by using GO/Au NPs as the SERS substrate[107]. Through controlling the depositing density ofAu NPs, highly dense hot spots with strong elec-tromagnetic coupling effect was produced. UsingGO/Au NPs as the substrate, Raman signal ofclenbuterol was enhanced 4.8 times in comparisonwith the use of sole Au NPs substrate. This pro-posed SERS-based method allows the selectiveclenbuterol detection with a LOD of 33.4 nM. Alsobased on gold nanoparticles, Muthaiah Shellaiah etal. developed a nanodiamond conjugated goldnanoparticles (ND@AuNPs) as colorimetric probefor the detection of clenbuterol in urine [108].Through modifying nanodiamonds to have thiolgroups, and then reacting with gold nanoparticles toobtain highly stable conjugates (ND@AuNPs). Thecomplexation of the amide (eC]O and eNeH)functional groups of ND@AuNPs with clenbuterolcauses aggregation and changes the color from winered to purple. This colorimetric method is used forselective detection of clenbuterol with a LOD of0.49 nM.To further improve the selectivity, immunofluo-
rescence method for clenbuterol analysis has beendeveloped. Conventional immunofluorescencetechnology requires complicated labeling proced-ure, which diminishes the sensing performances. Toavoid labeling, Yao et al. proposed a competitionstrategy using S/N-doped carbon quantum dots andclenbuterol antibody [105]. In their work, clenbu-terol antibody quenches the fluorescence of carbonquantum dots via amineeamine amineeaminecoupling reaction. The introduction clenbuterolleads to the formation of stable clenbuterolantibodyeclenbuterol complex, which liberatescarbon quantum dots and enhances the fluores-cence. This approach shows fluorimetric clenbuterolsensing in the concentration range from 0.07 to1.7 ng/mL, with a LOD of 23 pg/mL. In addition,
634 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
nanoparticles and gold nanoclusters can also beused in immunofluorescence technology. Forexample, Peng et al. proposed a fluorescenceimmunoassay method combined with immuno-magnetic separation [109]. In order to reduce thematrix effect, the author added immunomagneticnanoparticles to the swine urine sample to separatethe target substance immediately and effectively。Because it is loaded with Bovine serum albumin-gold nanoclusters (BSA-AuNCs) and artificial anti-gens, nanoflowers have the dual functions of fluo-rescence signal output and biological recognition.After adding this fluorescent-hybrid nanoflowers tothe sample solution that has been magneticallyseparated, the fluorescence intensity of the super-natant obtained by magnetic separation is directlyproportional to the concentration of clenbuterol.The assay has a linear response in the 0.5 ng/mL to40 ng/mL clenbuterol concentration range, and0.167 ng/mL limit of detection.
4.3. Melamine
Melamine, a triazine nitrogen-containing hetero-cyclic organic compound, has high nitrogen contentof 66.67%. Since normal technique for evaluating theprotein content in food is based on Kjeldahl method,in order to increase the tested protein content, thischemical has been added to milk by some unscru-pulous merchants. However, excessive uptake ofmelamine induces serious health problems, such askidney disease, chronic nephritis and bladder can-cer. Then, the exploration of rapid, sensitive, and
accurate method for detecting melamine in food,especially in milk is essential to Human health.In view of its amino-contained structure, mel-
amine shows high binding affinity to metal, likegold and silver. And thus, much effort has beendedicated to develop metal nanoparticle-basedsystem for melamine detection [110e114]. Forexample, Ren et al. developed a competitive mel-amine immunosensor based on branched poly-ethyleneimine functionalized rGO and Au NPsmodified electrode [112]. In this report, the authorfirst assembled the negatively charged sodium 3-mercaptopropane sulfonate to the Au electrodethrough the AueS bond. On this basis, the posi-tively charged branched polyethyleneimine func-tionalized reduced graphene oxide (BPEIGn)(prepared by a one-step catalytic reaction) isabsorbed on the electrode surface through electro-static interaction. Then, because the surface ofBPEIGn is filled with many amino groups andpositive charges, the negatively charged AuNPs arefixed on the electrode through covalent interactionand electrostatic adsorption. Subsequently, mel-amine is attached to the electrode surface by form-ing hydrogen bonds with polyethyleneimine. Theflexible structure of branched polyethyleneimineand its abundant amino groups can enhance itsinteraction with melamine. Finally, using bovineserum albumin (BSA) to block non-specific absorp-tion sites to obtain a melamine immunosensormodified electrode. It is precisely because of theprinciple of specific binding between antigen andantibody and the double amplification of BPEIGnand AuNPs that this sensor has excellent specificityand sensitivity. Therefore, using K3[(Fe (CN)6]/K4[Fe(CN)6] solution as the working electrolyte, theyachieved melamine analysis in the concentrationrange of 1 � 10�6 to 1 mM, with a LOD of2.66 � 10�7 mM.Nie et al. proposed a bowl-like pore array that
consists of hollow Au/Ag alloy nanoparticles, actingas hot-spots [111]. The designed bowl-like porearray showed high SERS activity toward melamine.Through the finite-difference time-domain simula-tions, the SERS enhancement mechanism wasattributed to the surface plasmon resonance of alloynanoparticles. The Raman shift 681 cm�1 that orig-inates from the in-plane deformation modes oftriazine ring was used as the reporting signal. Theintensity of signal increased upon increasing mel-amine concentration from 1 nM to 10 mM. To provethe practical application of this method, milk sam-ples spiked with melamine was investigated. Ac-cording to the results, melamine in milk could bedetected as low as 0.1 ppm, which is 10 times lower
Fig. 7. Representative SERS spectra of Sudan black B standard solutionswith different concentration. Reprinted from Ref. [103] with permissionfrom the Elsevier, Copyright 2019.
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 635
REVIEW
ARTIC
LE
than the permission set by Food and Drug Admin-istration (FDA).Beyond electrochemical reactivity and SERS ac-
tivity, Au NPs are also good fluorescence quenchersto organic and inorganic fluorophores. Usingbarium sulfate-coated CsPbBr3 perovskite nano-crystals (CsPbBr3 NCs@BaSO4) as the fluorophoreand Au NPs as the quencher, Li et al. reported afluorescence turn-on method for the detection ofmelamine [110]. The approaching of Au NPsquenched the fluorescence from CsPbBr3NCs@BaSO4 because of the intense electromagneticlocal field around Au NP surface. Addition of mel-amine weakened the binding affinity between AuNPs and CsPbBr3 NCs@BaSO4, and subsequentlyenhanced the fluorescence. With use of this strategy,they realized sensitive melamine determinationwith a LOD of 0.42 nM. In addition, this methodprovided good stability toward melamine sensingwith small relative standard deviation of 4.0%, andcould be applied to the analysis of dairy productsamples. Partial detection methods for illegal foodadditives were summarized in Table 3.
5. Conclusion and perspectives
In this review, we have displayed an overview onthe recent progresses of nanomaterial-assisted foodadditives analysis based on optical and electro-chemical techniques. The unique chemical andelectrochemical properties of nanomaterial endowthe sensitive detection of food additives includingcolorants, preservatives and illegal additives in foodsamples. These sensing systems usually show LODsat nM or mM levels, which meet the permission ofexpected food additives set by FDA or EPA. Withthe combination of multiplex detection tactic andarray-based sensing, a few examples accomplish themultiple targets analysis.Although the present works achieve successful
analysis of various food additives using nano-material-based optical and/or electrochemical sys-tems, there are still some challenges need to besolved. First, the highly reactive surface of nano-materials limits their use in complicated conditions.That is, some chemicals or substrates may haveinterference to the sensing of food additives. How-ever, food extracts usually contain many com-pounds, including targets and potential interferents.To avoid the false results, an extra separation pro-cess might be helpful before analysis. Second, thedesign of food additives detection system with auniversal strategy is lacking. For most systems, thesensing mechanisms are applicable for specific tar-gets. Other food additives with diverse molecularTa
ble3.
Summaryof
detectionmetho
dstowardillegal
food
additiv
es.
#Materials
Strategy
Targe
tan
alytes
Linea
rrange
LOD
Ref.
1La3
þ-dop
edCo 3O
4nan
ocube
s/SP
Eelectroa
nalysis
Sudan
I0.3e
300.0mM
0.05
mM
[100]
2ZnO
NPs/CPE
electroa
nalysis
Sudan
III
0.05e15
.0mM
0.00
254mM
[101]
3AuNPs
SERS
Sudan
blackB
0.05e2mg/mL
0.05
mg/mL
[103]
4su
lfuran
dnitroge
ndop
edcarbon
quan
tum
dots
immunofl
uorescent
clen
buterol
0.07e1.7ng/mL
23pg/mL
[105]
5polyo
xometalatean
dZrO
2
nan
ocom
posites
hyb
ridsmaterial/GCE
electroa
nalysis
clen
buterol
0.1e
1000
mM
5.03
�10
�3 mM
[106]
ractop
amine
3.0e
50mM
0.93
mM
6grap
hen
eox
ide/go
ldnan
ocom
posites
SERS
clen
buterol
0.05e1mM
3.34
�10
�2mM
[107]
7ba
rium
sulfate-co
ated
CsP
bBr 3
perov
skitenan
ocrystals
fluorescence
melam
ine
5.0e
500.0nM
0.42
nM
[110]
8hollow
Au/A
galloynan
oparticles
SERS
melam
ine
0.001e
10mM
0.00
1mM
[111]
9bran
ched
polye
thylen
eiminefunctionalized
reduced
grap
hen
eox
ide(BPEIG
n)/AuNPs/Au
electroa
nalysis
melam
ine
1�
10�6 e
1mM
2.66
�10
�7mM
[112]
10co
njuga
tedpolym
ernan
oparticles
(CPNs)
andAuNPs
fluorescence
resonan
ceen
ergy
tran
sfer
(FRET)
melam
ine
0.1e
1.5mM
0.00
17mM
[114]
636 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
structures can not to be detected with similar sys-tems. Thus, the exploration of a simple strategy forconstructing versatile detection systems isappealing. In consideration of the molecular recog-nition nature, molecularly imprinted polymer tech-nique may provide solution for this issue. By usingdifferent molecular templates, specific detection ofvarious food additives with similar protocols ispossible. Third, sole food additive is generallydetected based on nanomaterial-assisted analysis. Itis indicated in many works that food process isusually associated with different food additives. Forexample, colorants and preservatives exist at thesame time. To further evaluate the food safety, thedetection of multiple food additives from foodsamples needs to be finished in a single run/test. Asmentioned above, electrochemical methods possesspossibility to detect several food additives simulta-neously through different voltammetric peaks. Theoverlap of adjacent voltammetric peaks may havenegative effect. To realize multiple food additiveanalysis, array-based sensing might be a promisingtool. There are several advantages to array-basedsensing, including no demand of specific interac-tion, high-through, and wide signal input. In thiscase, to boost the analysis of multiple food additives,array-based detection with the combination ofnanomaterials is worthy to be tried. With theassistance of microchip technology, portable anal-ysis of multiple food additive with sensor array isalso possible in near future.
Conflicts of interest
The authors declare no competing financialinterest.
Acknowledgment
This work was supported by the Beijing NaturalScience Foundation (2202038), and the NationalNatural Foundation of China (22074005 and21605003).
References
[1] Blekas GA. Food additives: classification, uses and regula-tion. In: Caballero B, Finglas PM, Toldr�a F, editors. Ency-clopedia of food and health. Oxford: Academic Press; 2016.p. 731e6.
[2] Cooper PL, Marshall MR, Gregory III JF, Otwell WS. Ionchromatography for determining residual sulfite on shrimp.J Food Sci 1986;51:924e8.
[3] Ferrer Amate C, Unterluggauer H, Fischer RJ, Fernandez-Alba AR, Masselter S. Development and validation of a LC-MS/MS method for the simultaneous determination of af-latoxins, dyes and pesticides in spices. Anal Bioanal Chem2010;397:93e107.
[4] Lakshmi UR, Srivastava VC, Mall ID, Lataye DH. Rice huskash as an effective adsorbent: evaluation of adsorptivecharacteristics for Indigo Carmine dye. J Environ Manag2009;90:710e20.
[5] Ma Y, Zhang G, Pan J. Spectroscopic studies of DNA in-teractions with food colorant indigo carmine with the use ofethidium bromide as a fluorescence probe. J Agric FoodChem 2012;60:10867e75.
[6] Carlos KS, Treblin M, de Jager LS. Comparison and opti-mization of three commercial methods with an LC-MS/MSmethod for the determination of sulfites in food and bev-erages. Food Chem 2019;286:537e40.
[7] Jia W, Ling Y, Lin Y, Chang J, Chu X. Analysis of additivesin dairy products by liquid chromatography coupled toquadrupole-orbitrap mass spectrometry. J Chromatogr A2014;1336:67e75.
[8] Kaufmann A, Widmer M, Maden K, Butcher P, Walker S.Analysis of a variety of inorganic and organic additives infood products by ion-pairing liquid chromatographycoupled to high-resolution mass spectrometry. Anal Bio-anal Chem 2018;410:5629e40.
[9] Hao P-P, Ni J-R, Sun W-L, Huang W. Determination oftertiary butylhydroquinone in edible vegetable oil by liquidchromatography/ion trap mass spectrometry. Food Chem2007;105:1732e7.
[10] Herzog Gregoire, Kam Victor, Berduque Alfonso,Arrigan Damien WM. Detection of food additives by vol-tammetry at the liquid-liquid interface. J Agric Food Chem2008;56:4304e10.
[11] Majid A, Mehrnoosh S, Masoomeh Sayyar A, Asadollah M.Mediated electrochemical method for the determination ofindigo carmine levels in food products. Talanta 2017;173:60e8.
[12] Medeiros RA, Lourencao BC, Rocha-Filho RC, Fatibello-Filho O. Flow injection simultaneous determination ofsynthetic colorants in food using multiple pulse ampero-metric detection with a boron-doped diamond electrode.Talanta 2012;99:883e9.
[13] Harp BP, Miranda-Bermudez E, Barrows JN. Determinationof seven certified color additives in food products usingliquid chromatography. J Agric Food Chem 2013;61:3726e36.
[14] Misra R, Acharya S, Sahoo SK. Cancer nanotechnology:application of nanotechnology in cancer therapy. DrugDiscov Today 2010;15:842e50.
[15] Cai J, Niu H, Li Z, Du Y, Cizek P, Xie Z, et al. High-per-formance supercapacitor electrode materials from cellu-lose-derived carbon nanofibers. ACS Appl Mater Interfaces2015;7:14946e53.
[16] Liu Y, Kumar S. Polymer/carbon nanotube nano compositefibers-a review. ACS Appl Mater Interfaces 2014;6:6069e87.
[17] Chi D, Sun D, Yang Z, Xing Z, Li Z, Zhu Q, et al. Bifunc-tional nest-like self-floating microreactor for enhancedphotothermal catalysis and biocatalysis. Environ Sci Nano2019;6:3551e9.
[18] Pathakoti K, Manubolu M, Hwang HM. Nanostructures:current uses and future applications in food science. J FoodDrug Anal 2017;25:245e53.
[19] Bajpai VK, Kamle M, Shukla S, Mahato DK, Chandra P,Hwang SK, et al. Prospects of using nanotechnology forfood preservation, safety, and security. J Food Drug Anal2018;26:1201e14.
[20] Gupta A, Eral HB, Hatton TA, Doyle PS. Nanoemulsions:formation, properties and applications. Soft Matter 2016;12:2826e41.
[21] Correa DS, Pavinatto A, Mercante LA, Mattoso LHC,Oliveira JE, Riul A. Chemical sensors based on hybridnanomaterials for food analysis. Nanobiosensors 2017:205e44.
[22] Wang Y, Duncan TV. Nanoscale sensors for assuring thesafety of food products. Curr Opin Biotechnol 2017;44:74e86.
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 637
REVIEW
ARTIC
LE
[23] Lv M, Liu Y, Geng J, Kou X, Xin Z, Yang D. Engineeringnanomaterials-based biosensors for food safety detection.Biosens Bioelectron 2018;106:122e8.
[24] Downham A, Collins P. Colouring our foods in the last andnext millennium. Int J Food Sci Technol 2000;35:5e22.
[25] Pogacean F, Rosu M-C, Coros M, Magerusan L,Moldovan M, Sarosi C, et al. Graphene/TiO2-Ag basedcomposites used as sensitive electrode materials foramaranth electrochemical detection and degradation.J Electrochem Soc 2018;165:B3054e9.
[26] Gao Y, Wang L, Zhang Y, Zou L, Li G, Ye B. Electrochemicalbehavior of amaranth and its sensitive determination basedon Pd-doped polyelectrolyte functionalized graphenemodified electrode. Talanta 2017;168:146e51.
[27] WangM, Cui M, Zhao M, Cao H. Sensitive determination ofAmaranth in foods using graphene nanomeshes.J Electrochem Soc 2018;809:117e24.
[28] Karim-Nezhad G, Khorablou Z, Zamani M, Seyed Dorraji P,Alamgholiloo M. Voltammetric sensor for tartrazine deter-mination in soft drinks using poly (p-aminobenzenesulfonicacid)/zinc oxide nanoparticles in carbon paste electrode.J Food Drug Anal 2017;25:293e301.
[29] Sierra-Rosales P, Toledo-Neira C, Squella J. Electro-chemical determination of food colorants in soft drinksusing MWCNT-modified GCEs. Sens Actuators, B 2017;240:1257e64.
[30] Dorraji PS, Jalali F. Electrochemical fabrication of a novelZnO/cysteic acid nanocomposite modified electrode and itsapplication to simultaneous determination of sunset yellowand tartrazine. Food Chem 2017;227:73e7.
[31] Nu~nez-Dallos N, Macías MA, García-Beltr�an O,Calder�on JA, Nagles E, Hurtado J. Voltammetric determi-nation of amaranth and tartrazine with a new double-stranded copper (I) helicate-single-walled carbon nanotubemodified screen printed electrode. J Electroanal Chem 2018;822:95e104.
[32] Zhao X, Liu Y, Zuo J, Zhang J, Zhu L, Zhang J. Rapid andsensitive determination of tartrazine using a molecularlyimprinted copolymer modified carbon electrode (MIP-PmDB/PoPD-GCE). J Electroanal Chem 2017;785:90e5.
[33] Zhao X, Hu W, Wang Y, Zhu L, Yang L, Sha Z, et al.Decoration of graphene with 2-aminoethanethiol function-alized gold nanoparticles for molecular imprinted sensingof erythrosine. Carbon 2018;127:618e26.
[34] Arvand M, Pourhabib A, Asadi M. Template-based syn-thesis of uniform bimetallic nickel-tin oxide hollow nano-spheres as a new sensing platform for detection oferythrosine in food products. Sens Actuators, B 2018;255:1716e25.
[35] Zhao X, Ding J, Bai W, Wang Y, Yan Y, Cheng Y, et al.PEDOT: PSS/AuNPs/CA modified screen-printed carbonbased disposable electrochemical sensor for sensitive andselective determination of carmine. J Electroanal Chem2018;824:14e21.
[36] Ma X, Xie Y, Yu Y, Lu L, Liu G, Yu Y, et al. Three-dimen-sional b-cyclodextrin functionalized graphene aerogels: anenhanced electrochemical sensing platform for quantifica-tion of Ponceau 4R. J Electroanal Chem 2018;823:437e44.
[37] Hobbs CA, Koyanagi M, Swartz C, Davis J, Maronpot R,Recio L, et al. Genotoxicity evaluation of the naturally-derived food colorant, gardenia blue, and its precursor,genipin. Food Chem Toxicol 2018;118:695e708.
[38] Ji W, Zhang M, Wang T, Wang X, Zheng Z, Gong J.Molecularly imprinted solid-phase extraction methodbased on SH-Au modified silica gel for the detection of sixSudan dyes in chili powder samples. Talanta 2017;165:18e26.
[39] Wu X, Zhang X, Zhao C, Qian X. One-pot hydrothermalsynthesis of ZnO/RGO/ZnO@Zn sensor for sunset yellowin soft drinks. Talanta 2018;179:836e44.
[40] Bakheet AAA, Zhu XS. Poly(ionic liquid) immobilizedmagnetic nanoparticles as sorbent coupled with
fluorescence spectrophotometry for separation/analysis ofAllura red. J Mol Liq 2017;242:900e6.
[41] Tiwari S, Deb MK. Modified silver nanoparticles-enhancedsingle drop microextraction of tartrazine in food samplescoupled with diffuse reflectance Fourier transform infraredspectroscopic analysis. Anal Methods 2019;11:3552e62.
[42] Díaz de Le�on Zavala E, Torres Rodríguez LM, Montes-Rojas A, Torres Mendoza VH, Li~n�an Gonz�alez AE. Study ofelectrochemical determination of capsaicin and dihy-drocapsaicin at carbon paste electrodes modified by b-cyclodextrin. J Electroanal Chem 2018;814:174e83.
[43] Hassan AHA, Sappia L, Moura SL, Ali FHM, Moselhy WA,Sotomayor M, et al. Biomimetic magnetic sensor for elec-trochemical determination of scombrotoxin in fish. Talanta2019;194:997e1004.
[44] Wang H, Yao S, Liu Y, Wei S, Su J, Hu G. Molecularlyimprinted electrochemical sensor based on Au nano-particles in carboxylated multi-walled carbon nanotubes forsensitive determination of olaquindox in food and feed-stuffs. Biosens Bioelectron 2017;87:417e21.
[45] Kokulnathan T, Chen SM. Robust and selective electro-chemical detection of antibiotic residues: the case of inte-grated lutetium vanadate/graphene sheets architectures.J Hazard Mater 2020;384:121304.
[46] Gan T, Sun J, Meng W, Song L, Zhang Y. Electrochemicalsensor based on graphene and mesoporous TiO2 for thesimultaneous determination of trace colourants in food.Food Chem 2013;141:3731e7.
[47] Arvand M, Zamani M, Ardaki MS. Rapid electrochemicalsynthesis of molecularly imprinted polymers on function-alized multi-walled carbon nanotubes for selective recog-nition of sunset yellow in food samples. Sens Actuators, B2017;243:927e39.
[48] Yin ZZ, Cheng SW, Xu LB, Liu HY, Huang K, Li L, et al.Highly sensitive and selective sensor for sunset yellowbased on molecularly imprinted polydopamine-coatedmulti-walled carbon nanotubes. Biosens Bioelectron 2018;100:565e70.
[49] Rovina K, Siddiquee S, Shaarani SM. Highly sensitiveelectrochemical determination of sunset yellow in com-mercial food products based on CHIT/GO/MWCNTs/AuNPs/GCE. Food Contr 2017;82:66e73.
[50] Li L, Zheng H, Guo L, Qu L, Yu L. Construction of novelelectrochemical sensors based on bimetallic nanoparticlefunctionalized graphene for determination of sunset yellowin soft drink. J Electroanal Chem 2019;833:393e400.
[51] Ding Z, Deng P, Wu Y, Tian Y, Li G, Liu J, et al. A novelmodified electrode for detection of the food colorant sunsetyellow based on nanohybrid of MnO2 nanorods-decoratedelectrochemically reduced graphene oxide. Molecules 2019;24:1178.
[52] Ya Y, Jiang C, Li T, Liao J, Fan Y, Wei Y, et al. A zinc oxidenanoflower-based electrochemical sensor for trace detec-tion of sunset yellow. Sensors 2017;17:545.
[53] Ma X, Chen D, Tu X, Gao F, Xie Y, Dai R, et al. Ratiometricelectrochemical sensor for sensitive detection of sunsetyellow based on three-dimensional polyethyleneiminefunctionalized reduced graphene oxide aerogels@Aunanoparticles/SH-b-cyclodextrin. Nanotechnology 2019;30:475503.
[54] Yang H, Long Y, Li H, Pan S, Liu H, Yang J, et al. Carbondots synthesized by hydrothermal process via sodiumcitrate and NH4HCO3 for sensitive detection of tempera-ture and sunset yellow. J Colloid Interface Sci 2018;516:192e201.
[55] Ou Y, Wang X, Lai K, Huang Y, Rasco BA, Fan Y. Goldnanorods as surface-enhanced Raman spectroscopy sub-strates for rapid and sensitive analysis of allura red andsunset yellow in beverages. J Agric Food Chem 2018;66:2954e61.
[56] He H, Li P, Tang X, Lin D, Xie A, Shen Y, et al. Developingcysteamine-modified SERS substrate for detection of acidic
638 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
pigment with weak surface affinity. Spectrochim Acta MolBiomol Spectrosc 2019;212:293e9.
[57] Neng J, Xu K, Wang Y, Jia K, Zhang Q, Sun P. Sensitive andselective detection of new red colorant based on surface-enhanced Raman spectroscopy using molecularly imprin-ted hydrogels. Appl Sci 2019;9:2672.
[58] Feng P, Yilin Z, Zhiqin Y, Chao L. Determination of alizarinred S based on layered double hydroxides-improvedchemiluminescence from hydrogen peroxide and luminol.Anal Methods 2017;9:6468e73.
[59] Pan F, Zhang Y, Yuan Z, Lu C. Sensitive and selectivecarmine acid detection based on chemiluminescencequenching of layer doubled hydroxide-luminol-H2O2 sys-tem. ACS Omega 2018;3:18836e42.
[60] Su M, Chen P, Sun H. Development and analytical appli-cation of chemiluminescence with some super normalmetal complexes as oxidant. Trac Trends Anal Chem 2018;100:36e52.
[61] Siraj N, El-Zahab B, Hamdan S, Karam TE, Haber LH, Li M,et al. Fluorescence, phosphorescence, and chem-iluminescence. Anal Chem 2016;88:170e202.
[62] Zhao S, Chen C, Li Z, Yuan Z, Lu C. Hydroxyl radicalinduced chemiluminescence of hyperbranched poly-ethyleneimine protected silver nanoclusters and its appli-cation in tea polyphenols detection. Anal Methods 2017;9:3114e20.
[63] Magerusan L, Pogacean F, Coros M, Socaci C, Pruneanu S,Leostean C, et al. Green methodology for the preparation ofchitosan/graphene nanomaterial through electrochemicalexfoliation and its applicability in Sunset Yellow detection.Electrochim Acta 2018;283:578e89.
[64] Joshua CG, Tonya X, Siyue G, Yanqi Q, Lili H. Rapididentification of artificial and natural food colorants withsurface enhanced Raman spectroscopy. Food Contr 2018;92:267e75.
[65] Qin M, Li P, Zhou X, Zhu J, Wang H, Yang L. Cationicsurfactant regulated synthesis of Au nanorods for sensitivedetection of negatively charged colorants by surface-enhanced Raman spectroscopy. J Raman Spectrosc 2019;50:809e17.
[66] Andreou C, Neuschmelting V, Tschaharganeh DF,Huang CH, Oseledchyk A, Iacono P, et al. Imaging of livertumors using surface-enhanced Raman scattering nano-particles. ACS Nano 2016;10:5015e26.
[67] Sharma B, Frontiera RR, Henry A-I, Ringe E, VanDuyne RP. SERS: materials, applications, and the future.Mater Today 2012;15:16e25.
[68] Wu Y, Yu W, Yang B, Li P. Self-assembled two-dimensionalgold nanoparticle film for sensitive nontargeted analysis offood additives with surface-enhanced Raman spectroscopy.Analyst 2018;143:2363e8.
[69] Wu YX, Liang P, Dong QM, Bai Y, Yu Z, Huang J, et al.Design of a silver nanoparticle for sensitive surfaceenhanced Raman spectroscopy detection of carmine dye.Food Chem 2017;237:974e80.
[70] Ai YJ, Liang P, Wu YX, Dong QM, Li JB, Bai Y, et al. Rapidqualitative and quantitative determination of food colorantsby both Raman spectra and surface-enhanced Ramanscattering (SERS). Food Chem 2018;241:427e33.
[71] Jiang T, Wang X, Tang S, Zhou J, Gu C, Tang J. Seed-mediated synthesis and SERS performance of grapheneoxide-wrapped Ag nanomushroom. Sci Rep 2017;7:9795.
[72] Sharma S, Prakash V, Mehta SK. Graphene/silver nano-composites-potential electron mediators for proliferation inelectrochemical sensing and SERS activity. Trac TrendsAnal Chem 2017;86:155e71.
[73] Kailimai S, Ya Z, Shaona C, Shan Z, Yingshuang H,Jiacheng D, et al. Selectively encapsulating Ag nano-particles on the surface of two-dimensional graphene forsurface-enhanced Raman scattering. Appl Surf Sci 2019;492:108e15.
[74] Zhang X, Zhang J, Li W, Yang Y, Qin P, Zhang X, et al.Magnetic graphene oxide nanocomposites as the adsorbent
for extraction and pre-concentration of azo dyes in differentfood samples followed by high-performance liquid chro-matography analysis. Food Addit Contam 2018;35:2099e110.
[75] Carocho M, Morales P, Ferreira IC. Antioxidants: reviewingthe chemistry, food applications, legislation and role aspreservatives. Trends Food Sci Technol 2018;71:107e20.
[76] Esimbekova EN, Asanova AA, Deeva AA, Kratasyuk VA.Inhibition effect of food preservatives on endoproteinases.Food Chem 2017;235:294e7.
[77] Fan L, Hao Q, Kan X. Three-dimensional graphite paperbased imprinted electrochemical sensor for tertiary butyl-hydroquinone selective recognition and sensitive detection.Sens Actuators, B 2018;256:520e7.
[78] Alamo LS, Tangkuaram T, Satienperakul S. Determinationof sulfite by pervaporation-flow injection with ampero-metric detection using copper hexacyanoferrate-carbonnanotube modified carbon paste electrode. Talanta 2010;81:1793e9.
[79] Liu H, Na W, Liu Z, Chen X, Su X. A novel turn-on fluo-rescent strategy for sensing ascorbic acid using graphenequantum dots as fluorescent probe. Biosens Bioelectron2017;92:229e33.
[80] Mohammadzadeh-Aghdash H, Akbari N, Esazadeh K,Ezzati Nazhad Dolatabadi J. Molecular and technical as-pects on the interaction of serum albumin with multifunc-tional food preservatives. Food Chem 2019;293:491e8.
[81] Uzer A, Saglam S, Can Z, Ercag E, Apak R. Electrochemicaldetermination of food preservative nitrite with gold nano-particles/p-aminothiophenol-modified gold electrode. Int JMol Sci 2016;17:1253.
[82] Chen C, Yuan Z, Chang H-T, Lu F, Li Z, Lu C. Silvernanoclusters as fluorescent nanosensors for selective andsensitive nitrite detection. Anal Methods 2016;8:2628e33.
[83] Wang J, Zhu Y, Grimes CA, Nie Z, Cai Q. Eu,Sm,Mn-dopedCaS nanoparticles with 59.3% upconversion-luminescencequantum yield: enabling ultrasensitive and facile smart-phone-based sulfite detection. Anal Chem 2018;90:8658e64.
[84] Jin M, Huang L, Tang Y, Wang G, Ma Z, Yuan Z, et al. Rapidsulfite screening using nitrobenzofurazan anchored asym-metric naphthorhodamine via electrostatic attractionmediated reaction kinetics. Sens Actuators, B 2019;297:126748.
[85] Chen SM, Manavalan S, Rajaji U, Govindasamy M,Chen TW, Ajmal Ali M, et al. Determination of the anti-oxidant propyl gallate in meat by using a screen-printedelectrode modified with CoSe2 nanoparticles and reducedgraphene oxide. Mikrochim Acta 2018;185:520.
[86] Yue X, Luo X, Zhou Z, Bai Y. Selective electrochemicaldetermination of tertiary butylhydroquinone in edible oilsbased on an in-situ assembly molecularly imprinted poly-mer sensor. Food Chem 2019;289:84e94.
[87] Li Y, Chen FZ, Xu YT, Yu WJ, Li HY, Fan GC, et al. Self-assembled peptide nanostructures for photoelectrochemicalbioanalysis application: a proof-of-concept study. AnalChem 2019;91:12606e10.
[88] Wang Q, Ruan YF, Zhao WW, Lin P, Xu JJ, Chen HY.Semiconducting organic-inorganic nanodots hetero-junctions: platforms for general photoelectrochemical bio-analysis application. Anal Chem 2018;90:3759e65.
[89] Han F, Song Z, Nawaz MH, Dai M, Han D, Han L, et al.MoS2/ZnO-heterostructures-based label-free, visible-light-excited photoelectrochemical sensor for sensitive and se-lective determination of synthetic antioxidant propylgallate. Anal Chem 2019;91:10657e62.
[90] Sandeep S, Santhosh AS, Swamy NK, Suresh GS, Melo JS,Chamaraja NA. A biosensor based on a graphene nano-ribbon/silver nanoparticle/polyphenol oxidase compositematrix on a graphite electrode: application in the analysis ofcatechol in green tea samples. New J Chem 2018;42:16620e9.
[91] Chi M, Zhu Y, Jing L, Wang C, Lu X. Fabrication of oxidase-like polyaniline-MnO2 hybrid nanowires and their sensitive
JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640 639
REVIEW
ARTIC
LE
colorimetric detection of sulfite and ascorbic acid. Talanta2019;191:171e9.
[92] Ji D, Du Y, Meng H, Zhang L, Huang Z, Hu Y, et al. A novelcolorimetric strategy for sensitive and rapid sensing ofascorbic acid using cobalt oxyhydroxide nanoflakes and 3,3’, 5, 5’-tetramethylbenzidine. Sens Actuators, B 2018;256:512e9.
[93] Xiong C, Wang Y, Qu H, Zhang L, Qiu L, Chen W, et al.Highly sensitive detection of gallic acid based on organicelectrochemical transistors with poly (dia-llyldimethylammonium chloride) and carbon nano-materials nanocomposites functionalized gate electrodes.Sens Actuators, B 2017;246:235e42.
[94] Ng KL, Tan GH, Khor SM. Graphite nanocomposites sensorfor multiplex detection of antioxidants in food. Food Chem2017;237:912e20.
[95] Yang H, Lu F, Sun Y, Yuan Z, Lu C. Fluorescent goldnanocluster-based sensor array for nitrophenol isomerdiscrimination via an integration of hosteguest interactionand inner filter effect. Anal Chem 2018;90:12846e53.
[96] Yuan Z, Du Y, Tseng Y-T, Peng M, Cai N, He Y, et al.Fluorescent gold nanodots based sensor array for proteinsdiscrimination. Anal Chem 2015;87:4253e9.
[97] Bordbar MM, Hemmateenejad B, Tashkhourian J, Nami-Ana SF. An optoelectronic tongue based on an array of goldand silver nanoparticles for analysis of natural, syntheticand biological antioxidants. Microchim Acta 2018;185:493.
[98] Xie Y, Chen T, Guo Y, Cheng Y, Qian H, Yao W. RapidSERS detection of acid orange II and brilliant blue in foodby using Fe3O4@Au core-shell substrate. Food Chem 2019;270:173e80.
[99] Zhang D, You H, Yuan L, Hao R, Li T, Fang J. Hydrophobicslippery surface-based surface-enhanced Raman spectros-copy platform for ultrasensitive detection in food safetyapplications. Anal Chem 2019;91:4687e95.
[100] Mahmoudi-Moghaddam H, Tajik S, Beitollahi H. Highlysensitive electrochemical sensor based on La3þ-dopedCo3O4 nanocubes for determination of Sudan I content infood samples. Food Chem 2019;286:191e6.
[101] Heydari M, Ghoreishi SM, Khoobi A. Response surfacemodeling of electrochemical data for sensitive determina-tion of Sudan III in food products at the surface of ananocomposite modified electrode. Food Anal Methods2019;12:1781e90.
[102] Ye Q, Chen X, Yang J, Wu D, Ma J, Kong Y. Fabrication ofCuO nanoparticles-decorated 3D N-doped porous carbonas electrochemical sensing platform for the detection ofSudan I. Food Chem 2019;287:375e81.
[103] Zhao Y, Yamaguchi Y, Liu C, Li M, Dou X. Rapid andquantitative detection of trace Sudan black B in dyed black
rice by surface-enhanced Raman spectroscopy (SERS).Spectrochim Acta Mol Biomol Spectrosc 2019;216:202e6.
[104] Hu Y, Gao Z. Sensitive detection of Sudan dyes using tire-derived carbon dots as a fluorescent sensor. SpectrochimActa Mol Biomol Spectrosc 2020;239:118514.
[105] Yao D, Liang A, Jiang Z. A fluorometric clenbuterolimmunoassay using sulfur and nitrogen doped carbonquantum dots. Microchim Acta 2019;186:323.
[106] Zhang L, Wang Q, Qi Y, Li L, Wang S, Wang X. An ultra-sensitive sensor based on polyoxometalate and zirconiumdioxide nanocomposites hybrids material for simultaneousdetection of toxic clenbuterol and ractopamine. Sens Actu-ators, B 2019;288:347e55.
[107] Sun Y, Chen H, Ma P, Li J, Zhang Z, Shi H, et al. In situsynthesis of graphene oxide/gold nanocomposites as ul-trasensitive surface-enhanced Raman scattering substratesfor clenbuterol detection. Anal Bioanal Chem 2020;412:193e201.
[108] Shellaiah M, Simon T, Venkatesan P, Sun KW, Ko F-H,Wu S-P. Nanodiamonds conjugated to gold nanoparticlesfor colorimetric detection of clenbuterol and chromium(III)in urine. Microchim Acta 2017;185:74.
[109] Peng T, Wang J, Zhao S, Xie S, Yao K, Zheng P, et al.A fluorometric clenbuterol immunoassay based on the useof organic/inorganic hybrid nanoflowers modified withgold nanoclusters and artificial antigen. Microchim Acta2018;185:366.
[110] Li Q, Wang H, Yue X, Du J. Perovskite nanocrystalsfluorescence nanosensor for ultrasensitive detection oftrace melamine in dairy products by the manipulation ofinner filter effect of gold nanoparticles. Talanta 2020;211:120705.
[111] Nie B, Luo Y, Shi J, Gao L, Duan G. Bowl-like pore arraymade of hollow Au/Ag alloy nanoparticles for SERSdetection of melamine in solid milk powder. Sens Actua-tors, B 2019;301:127087.
[112] Ren Q, Shen X, Sun Y, Fan R, Zhang J. A highly sensitivecompetitive immunosensor based on branched poly-ethyleneimine functionalized reduced graphene oxide andgold nanoparticles modified electrode for detection ofmelamine. Food Chem 2020;304:125397.
[113] Wang M, Zhao W, Lei S, Zou W, Hu W, Liu H, et al.Rational design of MnO nanoparticles assemblies for sen-sitive magnetic relaxation detection of melamine. Talanta2020;208:120359.
[114] Zhang CJ, Gao ZY, Wang QB, Zhang X, Yao JS, Qiao CD,et al. Highly sensitive detection of melamine based on thefluorescence resonance energy transfer between conjugatedpolymer nanoparticles and gold nanoparticles. Polymers2018;10:873.
640 JOURNAL OF FOOD AND DRUG ANALYSIS 2020;28:622e640
REVIEW
ARTIC
LE
