Instrumental Analysis, LaboratoryOral PresentationNikko BacalzoDouglas DyJeremy LyFrance Tan

Determination of Anions in Toothpaste by Ion Chromatography Instrument Used:Ion Chromatography

FLUORIDE

http://toxicfreekidsblog.org/2011/07/toxic-toothpaste/http://www.webmd.com/oral-health/image-collection-oral-health#phototake_rm_photo_of_tooth_illustration.jpg

http://www.skepticnorth.com/2010/10/fluoridiated-water-debate-returns-nothing-new-is-said/http://www.fluoridation.com/teeth.htm

ION CHROMATOGRAPHY

ION CHROMATOGRAPHY

http://www.separations.us.tosohbioscience.com/ServiceSupport/TechSupport/ResourceCenter/PrinciplesofChromatography/IonExchange

ION CHROMATOGRAPHY

Injection valve

Readout

Mobile phase/ solvent reservoir Pump Column Detector

Excess/waste

Filter

Data and Results

Data and Results

0 5 10 15 20 25 30 350

50000

100000

150000

200000

250000

300000

350000

f(x) = 21381.584705256 x + 50726.6666666663R² = 0.892850575318569

concentration (ppm)

peak

are

a

Fluoride calibration

curve

Data and Results

0 5 10 15 20 25 30 35 40 450

50000

100000

150000

200000

250000

f(x) = 31566.7370857077 x − 30763.6666666669R² = 0.861303259627165

concentration (ppm)

peak

are

a

Chloride calibration

curve

Data and Results

BrandIon n

%(w/w) mean ± std dev

%RSD

Sensodyne

F 3 -- --

Cl 2 a0.00923 ± 0.00002

0.270

Colgate F 3 -- b --Cl 3 -- --

HapeeF 3 -- --Cl 2 a 0.016 ± 0.002 15.3

Close-Up

F 3 -- --Cl 3 -- --

Data and Resultsconc

(ppm)spiked (mg)

unspiked (mg)

added

(mg)

%recovery

SPIKE 40.62 2.031 0.02052 1.344 149.6

Conclusion• Four toothpaste brands were analyzed for their fluoride

and chloride contents (Sensodyne, Colgate, Close-Up and Hapee).

• Standards were run in the ion chromatograph, and the retention times and the concentration-peak area relationships of each were drawn from the data.

• Out of which only Sensodyne and Hapee showed quantifiable amounts of chloride in the toothpaste formulation.

• Calculation yielded concentrations of 0.00923% and 0.016% chloride in both toothpastes, respectively.

• Other samples had no sufficiently quantifiable amounts of both anions, suspected to be consequence of matrix effect.

Recommendations• Use other MP: carbonate/bicarbonate buffer, KOH• Use gradient elution• Standard addition instead of calibration curve• Homogenization of samples• Analyze other anions (MFP, benzoate, sulfate,

phosphate)• Method validation

References• Takahara, Y, et al. Photooxidation of organic

compounds in a solution containing hydrogen peroxide and TiO2 particles under visible light. Journal of Applied Chemistry. Vol.35, 793-797. <http://www.springerlink.com/content/t866330021785302/>

• Shimadzu Corporation. The UV-2401PC: A Superbly Engineered Instrument. Accessed on May 21, 2012. <http://www.pa.ibf.cnr.it/web/pdf/12.pdf>

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