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Separation and Quantitation of Anionic, Cationic,and Nonionic Surfactants by TLC

ARTICLE in JOURNAL OF LIQUID CHROMATOGRAPHY · JANUARY 1983

DOI: 10.1080/01483918308066867

CITATIONS

12

READS

43

2 AUTHORS, INCLUDING:

Daniel W. Armstrong

University of Texas at Arlington

652 PUBLICATIONS 23,109 CITATIONS

SEE PROFILE

Available from: Daniel W. Armstrong

Retrieved on: 07 December 2015

http://www.researchgate.net/profile/Daniel_Armstrong?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_4http://www.researchgate.net/profile/Daniel_Armstrong?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_5http://www.researchgate.net/profile/Daniel_Armstrong?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_5http://www.researchgate.net/?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_1http://www.researchgate.net/profile/Daniel_Armstrong?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_7http://www.researchgate.net/institution/University_of_Texas_at_Arlington?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_6http://www.researchgate.net/profile/Daniel_Armstrong?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_5http://www.researchgate.net/profile/Daniel_Armstrong?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_4http://www.researchgate.net/?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_1http://www.researchgate.net/publication/233232136_Separation_and_Quantitation_of_Anionic_Cationic_and_Nonionic_Surfactants_by_TLC?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_3http://www.researchgate.net/publication/233232136_Separation_and_Quantitation_of_Anionic_Cationic_and_Nonionic_Surfactants_by_TLC?enrichId=rgreq-e6dbbece-bc1e-4827-98ba-b0a332a4cc33&enrichSource=Y292ZXJQYWdlOzIzMzIzMjEzNjtBUzoxNjU3MTM2OTYyNzIzODRAMTQxNjUyMDYzMjY5Mg%3D%3D&el=1_x_2


2/12

TLC

s a

potent ia l ly

powerfu l

technique

or the separat ion

of

surfactants.

Reversed

hase

hin

layer

chromatograghy

RPTLC)

can

be used

o separate

ent i re

classes

of

surfactants

( i .e. '

anionics

f rom

nonionics

f rom

cat ionics) .

Conversely '

s i l ica

ge1

can

be

used

o separate

ndividual

anionic

or

cat ionic

surfac-

tants

f rom other

'sim' i larly

charged

surfactants.

RPTLC

an also

be used o separate indiv idual nonionic surfactants. Using two

d. imensjonal

LC

(wi tn a specia l

s j l ica

gel

p late

contain ing

a 2.5

cm

str ip

of

reveised

phase

materia' l

a long

one

gdge)

I

complex

mixture

of

surfactants

tvas

i rst

f ract ionated

into

classes

and

then

(using

the second

di rnension)

nto

indiv idual

components.

Standdrrd

ianning

densi tometry

was used

or

quant i tat ion.

JOURNAT

F LTQUTD

CHROMATOGR3PHY,

(1),

23-33

(1983)

SEPARATION

ND

UANTITATION

F

ANIONIC,

CATIONIC

ND

NONIONIC

URFACTANTS

Y TLC

D.l^J.

rmstrong

ndG.Y.

St ine

Department

f

ChemistrY

Georgetown

niversitY

Washington,

C 20057

ABSTRACT

I

NTRODUCTION

The

analysis

of surfactants

(e.9. ,

detergents '

soaps'

etc. )

can

be a d i f f icu l t

analyt ical

problem.

Surfactants

are

general ly

somewhat

oluble

in

both water

and

organic

solvents.

They con-

cent rate

at

inter faces

and

tend

to

bjnd to

anything

avai lable

( l

12).

There

are

a var iety

of

spect rometr ic,

t i t r imet r ic,

atomic

absorpt ion

spect rometr ic

and

ion-select jve

elect rode

methods

or

the

analys. is

of

surfactants

(3-11

.

Al l

of

these

techniques

have

Copyright

@

1983

by

Marcel

Dekker,

lnc.

0

48-399/83/060

023$3.s0/0


3/12

zq

ARMSTROI{G AND STINE

the charactenist ic

of

being

select ive for certa in

funct ional

groups.

For example

oth

the

sodium

dodecylsul fate

elect rode and

the methylene

blue

complex

spect rophotometr ic

methods

re seiec-

t ive

for

surfactants

wi th sul fate or sul fonate

funct ional

groups.

Consequent ly

hese techniques

give posi t ive

r"esponsesor a

var iety of

homologous,somer^ic

nd

even st ructural ly d issimi lar

anionic surfactants.

Another

shortcoming f

these techniques s

that

one class

of

surfactants cannot

be ef fect ively analyzed

n

the

presence

of another ' . The

so-cal ' led neut ra l izat ion ef fect

of

cat ionic wi th anionic

surfactants is wel l documented

12).

As a

resul t of these l imj tat ions, the

analyst has increasingly

turned

to

physicochemical

echniques

which

pnovide

nformat ion on the

tota l

surfactant content

in a sample

13)

or to

chromatography

(14-16).

Becausemost surfactants are nonvolat i le wi thout der i -

vat izat ion,

LC

or TLC

methods re of ten

preferred.

The use of

TLC

to separate a m' ixture

of anionic surfactants was

recent ly

demonst rated

17).

In

th is work we

not

only

demonst rate he

separat ion

of ident ical ly

chargedsurfactants

f rom

each other

but

also the TLCsepanat ion

of the

three major c lasses of surfactants

(

i .e. , anionic,

nonionic and

cat ionic) .

MATERALS

Whatmaneversed

phase

TLC

plates

(KC18F),

j l ica

gel p lates

(K5F)

and hybr id Mul t i -K

plates

(CS5)

were

act ivated at l l5oC for

two

hours

before use. Cetyl t r imethylammonium

romide

CTAB,

Sigma),

cety lpyr id in ium

chlor ide

(CPC,

Sigma),

cety l t r imethyl -


4/12

SEPARATION

F

SURFACTANTS

Y TLC

ammonium

hlor ide

(CTAC,

Pfal tz &

Bauer) ,

dodecylamine

DA'

Aldnich), octadecylamine.

0A,

Eastman),

odium

dodecylsul fate

(SDS,

Bio Rad),

dodecy' lbenzenesul fonate

DBS,

Pfal tz &

Bauer) ,

sodium

diocty l

sul osuccinate

(SD0S,

Aldr ich)

and

sodium aurate

(SL,

Pfal tz &

Bauer)

were

recrysta l l ized

three

t imes

f rom

ethanol -water

before use.

The nonionic

surfactants

Tr i ton X

100

(TX

100,

Bio Rad), Surfynol

465

(S

465'

Ai r Products)

and

Igepol

C0-530

IC0-530,

GAF)

were used as

received. IC0-530

s

nonylphenoxypoly(ethyleneoxy)ethanol

here

he

hydrophi1c

poly(ethyleneoxy)ethanol

head-group"

verages

ive

uni ts in

length. TX 100

is

dodecylphenoxypoly(ethyleneoxy)ethano1.

465

is a

poly(ethyleneoxy)ethanol

averaging

en uni ts) adduct of

2,4,7,9- le lnamethyl -5-decyn-4,7-dio l .

Gold

able sodium

tet raphenylborate

(Aldr jch)

was

used

as received.

Methanol ,

ethanoi ,

methylenechlor ide

and

glacia l

acet ic

acid

(Baker)

were

also

used as

received.

Al l

separat ions

were

done

n

a l1

3/4

in. long,4

in. wide

and

l0

3/4

in.

h igh

sealed

chromaf lex

developing

ank.

The

plates were not pre-equi l ihrated wi th solvent vapor before use.

Separat ion

of

anionic

surfactants:

I

ut

of 0.1

M

SDS'

SL'

DBS

and S|JOS

as spot ted I

cm

from

the

bot tomof a 5

x 20 cn s i l ica

ge1 plate.

The

mobile

phase

consjsted

of

8:1

(v:v)

methylene

chlor jde:methanol .

The

addi t ion

of very

small

amounts f acet jc

acid to the mobi le

phase

ended o

increase

he R1's but d id not

METHODS


5/12

ARMSTRONG

ND

STINE

af fect the

resolut ion. Spots

were

vjsual ized

by

exposure

o

12

vapor.

Separat ion of cat ionic surfactants: I

y l

of 0. i

M

CPC,0A, IJA

and CTAC r CTABwas spotted 1 cm from the bottom of a 5 x 20 cm

si l ica

ge1

p1ate.

The

mobile

phase

consisted

of

8:1:0.75

(v:v:v)

methylenechlor ide:methanolacet ic acid.

Spots

were

visual ized

by

exposure o I2

vapor.

Separat ' ion

f nonionic surfactants:

1

ut

of

10%

TX

100, IC0-530

and S 465

rvere

spot ted on

a

5

x

20

cm reversed

phase

(C16)

plate.

The mobi le

phase

consisted

of

8:2

(v:v)

ethanol :2%

odium

tet raphenylborate(aq). The

purpose

of sodium

etraphenylborate

was to

prevent

the

spots

f rom

streaking. 12 vapor was used for

v isual zat ion.

Separat ionof

anionic, cat ionic and nonionic surfactants: A

Whatman S5, Mul t i -K, KC18F/KsF0

x

20

crn

plate

was

pre-

developed n

ethanol and then

act ivated at 115"C or

2

hours.

Each surfactant mjxture

was

spot ted

(0.5

ur)

at a

point

on the

reversed

phase

st r ip. The

ent ine

20

x

20

cm

plate

was then

developedwi th 75%ethanol in the dinect ion of the reversed

phase

st r ip. Development

as stoppedwhen he solvent

f ront

was

2

cm

from

the top of

the

plate.

Under

hese

condi t ions, a l l

anionic surfactants

t ravel at or very

nean he solvent

f ront

( i .e. , <

2

cm), a l i cat ionic

surfactants remainat

or near

the

or ig in

of the reversed

phase

st r ip

(


6/12

r$

fi

,j

r$

rd

SEPAMTION

F

SUMACTANTS

Y TLC 27

surfactants

separate

between he anionics

and cat ionics. The

20

x 20

cm

plate

is

then cut

into three separate

sect ions in a

di rect ion

penpendicular

o the

f i rst development .

The

f i rst

cut should

be

2.5 to 3

cm below he

solvent

f ront .

This wi l l iso late the anionic surfactants. The

second

cut should

be

3

cm

above he

or ig in. This

wi l l

iso late the cat ionic surfac-

tants.

Penpendicular econdary

evelopment f the

plates

con-

ta in ing the cat ionic and

anionic sur ' factants

(af ten

react ivat ion

of the

plates)

wi l l

g ive

completeseparat ion of these

species.

The mobi le

phases

or secondary evelopment re, 8:1

(v:v)

MeCl2:Me0H

or the anionic

surfactants

and

B:1:0.5

(v:v:v)

MeCl2:Me0H:HOAcor

the cat ionic surfactants.

I f

one develops

the

ent i re

p1ate

in

the second

di rect ion

wi thout isolat ing the

anionic and cat ionic

surfactants

as indicated, the nonionic

sur" -

factants

tend to spread and coat the s i l ica

ge1 port ion

of the

plate

thereby obscur ' ingal1 other components.Visual izat ion is

wi th

I2

vapor.

Quant i tat ion

of surfactants: Scanning

ensi tometnywas done wi th

a

Shimadzu

odel

910

inst rument .

Surfactants

could

be

detected

di rect ly in the absorbance-ref lectance ode t 215 nm. l )etect ion

l imi ts

wene ower

when he

developed

plate

was exposed o

I2

vapor

and scanned t

405

nm

(in

the absonbance-tnansmit tanceode).

RESTJLTS

ND

DISCUSSION

One's approach

o the TLCseparat ion

of

surfactants

in a

mixture

is

largely

contnol led

by

the change f the surfactant


7/12

ARMSTRONGND STINE

head-groups s wel l as the d iversi ty of the

sample. Si l ica

ge' l

is adequate or the separat ion

of anionic or cat ionic surfactants

f rom other ident ical ly charged

species. Nonionic surfactants are

best

separated

by

reversed

phase

TLC

RPTLC).

Even

n

RPTLC

nonionjc

surfactants tend to st reak unless a

"1

pophi l ic sal t "

such as sodium et raphenylborate

is

added. Table 1 surnmarizes

TABLE

Exper imental

Condi t ions and

R1

Values of

Indiv idual ly

SeparatedAnionic, Cat ionic and Nonionic Surfactants

Compound Stat i onary Mobi e

Phase Phase

$

R1

Anionic

Surfactants

I .

SDS

2.

DBS

3. SL

4.

SDoS

Cat ionic Surfactants

1.

CTAB

t.

r.

I t iu

3.

CPC

4.

DA

5. 0A

Nonionic Surfactants

1.

TX

100

2.

S

465

3. IC0-530

0.15

0

09

0

70

4,28

0.2r

0.20

0.27

0,42

0 55

0.54

0

70

0 45

aSi l ica

Gel

D

C1g

eversed

phase

c8:1(v:v)

MeCl2:MeOH

d8,1,0.75

(v:v:v)

MeCi2:MeOH:H0Ac

e8:2

(v

:v) Et0H:2%

odi

um etraphenyi

orate(6q)


8/12

SEPAMTION

OF

SURFACTANTS

Y

TLC

29

t:"*:l1r'11]f

andBottomections

-____________f

@

I

E

o

lt ;;l;

rec

;'$

,firb.).,l}

CpC

DA

i,: FliJ

OA

clF;+

KCl8F

Figure

1: Schemat ic f a two djmensional

TLC

separat ion of

e leven surfactants

on a

composi t

eversed

phase-

si l ica

ge1 p1ate.

The

f i rst

development

on

the

reversed

phase

st r ip)

separated he surfactants

according to c lass.

Secondany

evelopment

f the top

and bot tom sect ions of the plate r"esul ts in complete

separat ion of

jndiv idual

sunfactants.

SDS

sodium

dodecyl

u l ate, DBS dodecyl enzenesul

onate,

NL

=

sodium aurate, S

465

=

Surfynol

465, TX

100

=

Tri ton

X100, IC0-530

=

Igepol C0-530,

CTAC cetyl t r i rnethy-

I

ammoni

m chlor i de,

CPC cetyl

pyr i

di

n um chlori de,

DA

=

dodecylamine, A

=

octadecylamine.

t ies

SDS

DBS

'fll'

'#

sDs

r,i#

NL

{r

",$:

url

ig

TX100

$l

tco-530


9/12

30

ARMSTRONG

AND

STINE

the separat ion

condj t ions

for each c ' lass of

surfactants. The

Rr 's

of

the cat ionic

sunfactants can

be al tered

( i .e. ,

increased)

consider"ablywi th a s l ight

increase

in

the concent r^at ion

f

ace-

t ic acid

in

the mobi

e

phase.

The separat ion

of surfactants wi th

' ident ical hydrophyl ic headgnoups i .e. , DAand 0A or Tx 100 and

IC0-530)

s dependent n the s ize of

the

hydrophobic

ta j l " .

Genenal ly

he

larger

the hydrophobic

ort ion

of

the

sunfactant ,

the

greater

the R1.

The

analysis of

solut ions contajn ing sunfactants of

d i f -

ferent

char^ge an

be

a

di f f icu l t

pr^ocess

ecause

f

precip i tat ion

and

"neut ra l

zat ion" ef fects

(12).

RPTLC, owever,can

be

used

to sepanate

sunfactants

by

class

(see

Figure

1).

A

75%

ethanoi

mobi le

phase

ends

to cannyanionic sunfactants

wi th the

solvent

f ront and

leave

cat ionic surfactants

near the onig in.

Perpen-

dicular secondary eveloprnent

f

p late

sect ions

near the

solvent

f ront and oni

gi

n wi

l then sepanate he

ani

on

c and cat i onic sur ' -

factants into indiv idual

compounds.The

secondany evelopment

cannies thd surfactants

f rom the reversed

phase

st l ip

into the

si l ica

gel port ion

of the

plate

whene

nact ionat ion occuns

(Figune

1).

Secondary

evelopment

f the

whole

TLC

plate

or the

sect jon

of

plate

contain ing

the

nonionic surfactants

produced

i

ndist i

nguishabl smears

oven

muchof the

p1

te.

Quant i tat ion

of sur" factants

by

scanning

densi tometry

s

a

relat ively

st ra ight

forwar"d

nocess.

I t

is

possib le

to d inect ly

scan

unt reated spots

at wavelengths

rom

200

to

215

nm.

Sen-

si t iv i ty

and select iv i ty

can

be enhanced

.yusing a

vaniety of


10/12

SEPARATION

F SURFACTANTS

Y TLC

4812

CTAC

Amount,

ll g

Figure 2: Cal ibrat ion plot of peak area vensus arnount of th e

standard

sunfactant (CTAC)

chromatographed.

The

' insent

shows

the

actual peaks

obtained

from

scanning

densitometery

(at

405 nm).

visual

zat ion

on

charr ing

techniques

(17,

1g). F igure

2 shows

a

scan

of four

GTAC

tandards

(r

=

405 nm

af ten

visual izat ion

wi th

I2

vapor)

and the

corresponding

al ibrat . ion

curve.

I t

is

appar"ent

rom

the

l . i terature

that

exhaust ive

chroma_

tographic

separat ions

are

pr"esent iy

he

most

ef fect ive

means

f

analyzing

complex

surfactant

mixtur"es.

TLC

s

shown

o be

a

highly

ef f ic ient

and inexpensive

echn. ique

or

the

analysis

of a

var iety

of

surfactant

and

surfactant

mixtures.

3t

N

c

@'

96 4

I

6

o


11/12

32

ARMSTRONGND STINE

ACKN()l,lLEDGEMENT

This

work was supportedby

grants

f rom the

Nat ional

Science

Foundat ion

CHE-8119055)

nd Whatman

hemicalSeparat ion

Divis ion, Inc. We

gratefu l ly

acknowledge

hei r assistance.

l .

RE ERENC

S

Fendler ,

J.H.

and Fendler ,

E.J. , Catalysis in Micel lar

and

Macromolecular

ystems,Academic ress, NewYork,

1975.

Rosen,

M.J. ,

Surfactants and

Inter facia l

Phenomena,

ohn

t , | i ley

& Sons, NewYork,

1978.

|^ lang,

.K.

and

Langley, D.F. ,

N.

Engl . WaterŴonks

ssoc. ,

89, 301

(1975).

Wang,

L.K.

and Ross, R.G. ,

Int . J. Envi ron. Anal .

Chem.,4,

285

(1976).

5. Higuchi ,

K. , Shjmoishi , Y. ,

l ' f iyata,

H. , Toei , K. and

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33

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