Stabilized Diazonium Salts as Analytical Reagents for the


Stabilized Diazonium Salts as Analytical Reagents for the Determination of Air-Borne Phenols and Amines. G. A. Lugg. Anal. Chem. , 1963, 35 (7), pp 89...
0 downloads 0 Views 636KB Size


left lighted day and -:light. The bnckground was determined by routing the ozone-carrying air t.tlrough a colunin nf Iabex dchris or of wtivated charcoal. .\t) both levels the ozone concentraticm found by titra.:,ion corresponded withiii to the concentration drtcrinined g:ilv;ttiicnllj~. DISCUSIION

Electrolyte. T h e adclition of n trace of ioclidc t o t h e bromide wis desirabk t o ensure n quantitative conversion of t h e ozone. T h e mechanism 01’ this beneficial synergism is not clear. Possibly t h e anion BrIBr- is involTred. Iodide alone, in large enough concl:ntration, without bromide, also converts quickly and quantitatively to free halogen, but iodide is much more prone than bromide to react with dissolved osygen, and also with the traces of nitrogen dioxide which often accompany ozone-e.g., from welding arcs. A t high iodide level the side reaction with oxygen would cause a high background, and the side reaction with nitrogen dioxide would cause too high increments upon admission of sample. With bromide plus a trace of iodide the uptake of ozone is sufficiently fast, yet neither the background nor the interference of nitrogen dioside is appreciable. Because of the shortiiess of the bubble chain the absorption of KO2 is only partial. Most of the part that is absorbed hydrolyzes harmlessly according t,o Choice of

3 NO,

+ H?O

+

:YO

+ 3 ITNO3

and only a very small fraction of t,hp KO,liberates halogen. Life. If t h e supply of ozone is relatively high---c.g., 100 x7.p.m. of Oa in 100 mi. of air p w niinirt,c,, corresponding to 1338-pa. output----the capacitv of the carhon surface for rhemisorpt,ion may become eshaust)rtl. How soon this will happrn depend.: o i i the quantity, nature, and liistory of the anode material used. - i n advance indication that exhaustion is approached is a sluggish response bo ozone. Eventually free bromine builds up in the electrolyte. I n the continuous monitoring of atmospheric ozone, the amount of carbon roughly suggested by Figure 1 should be sufficient for many months of operation. At high concentrations (unless brought down by dilution as described) larger carbon beds are indicated. It is possible to use the same carbon bed indefinitely, if after prolonged use at high ozone level it is “charged” by a cathodic treatment. -is the auxiliary anode a platinum wire in a separate glass t’himble with KCI solution may be used, with a paper wick junction reaching into the cell electrolyte during the treatment a t the point where normally the air leaves the cell. Other Applications. The c ~ lshould l he applicable t o the continuous a n d ysis of reducing species and of olefins in a gas stream. To this end t h e stream n~ould be pro\-ided n-ith a const,ant background of ozone generated pliotochemically, by silent discharge, or by electrolysis. .4 reducent species emerging in the air carrier stream would depress the level of ozone and

therefore the galvanic output of the cell.

A transiently emerging reducent would generate a negative peak in the recording of an area stoichiometrically related to the quantity of this species. The cell may thus serve as a not very fast, but selective and highly sensitive detector for gas chromatography. The carrier qtream leaving the column may be made to converge with a stream of ozonized air, and the mixed stream passed into the ozone sensor. It is also possible to mix the carrier leaving the column with air and to irradiate the reducent and oxygen together. The procedure outlined for ozone is, evidently, also applicable to the determination of free halogen, which may enter the cell carried b y a gas stream or be added to the cell as a batch sample. Indirect analysis should be possible in this way of many oxidants producing free halogen, and of many reducents consuming free halogen. The writers believe that the cell described opens the way for a new analytical technique, “galvanic halometry.” LITERATURE CITED

(1) Bowen, I. G., Regener, V. H.. J . Bpmhus. Res. 56. 307 (19513. (2) B&w, A. IT.’, M i l h d , J. R., Proc. Roq. SOC.(London) A256, 470 (1960). (3) Brewer, A . IV., Milford, J. R. ( t o M a s t D e v e h n i e n t Co.), U. S. Patent 3,038,848( J i n e 12, 1962). 14) Rwener. V. H.. Armed Services Tech. ’ Inforom. Aiency, ASTIA Rept. AD 254,270 (1960). (5) Regener, V.H. Advan. Chem. Ser., No. 21, 134 (1959).

RECEIVED for review September 26, 1962. Accepted March 28, 1963.

Stabilized Diazonium Salts as Analytical Reagents for the Determination of Air-Borne Phenols and Amines G. A. LUGG Department of Supply, Australian Defence Scientific Service, Defence Standards Laboratories, Maribyrnong, Victoricr, Australia

b Commercially-available stabilized diazonium salts h a w been used for simple and rapid plpocedures for the determination of 24 toxic phenols and aromatic amines. After initial spottesting with 25 diazci reagents a t four p H levels optimum reaction conditions were determined. ‘The vapor of a representative seleciion of the compounds was sampled and in each case a t least 8OY0 of the amount recovered was collected in the first bubbler. Interference is likely to b e mainly from accompanying nitro compounds. The sensitivity of the methods varies considerably, but the corn-

pounds can all b e determined in air a t concentrations of interest in hygiene studies. Data are presented on the precision and accuracy of the methods.

T

for the determination of phenols is the coupling reaction of aromatic amine-nitrous acid-phenol; the diazo reagent prepared from sulfanilic acid has been widely used (S), but i t is unstable and must be prepared immediately before w e . d favored procedure for amines involves diazotization with nitrous acid and then reaction with a suitable coupling agent ( 2 ) . HE CLASSICAL METHOD

The advantages of stabilized diazonium salts over the diazotization procedure were noted by Pearl and lIcCoy (6, 7 ) who employed commercially-produced, stable diazo salts as chromatographic spray reagents for phenolic compounds related to wood chemistry, and also by Lambert and Cates (4) who used polyanion-stabilized diazonium cations as spot test reagents for phenols and amines. Commercial diazonium salts have therefore been investigated as reagents for the determination of toxic phenols and amines in air. Employing the most suitable conditions of pH and the VOL. 35, NO. 7. JUNE 1963

899

Table 1.

S.D.C. color index diazo compound number

I.C.I.fI.X.7,. “Brentamine” salt

Stabilized diazo salt of

2 3 4

EXPERIMENTAL

Apparatus. T h e spectra were recorded on a SP700 spectrophotometer;

2-.4mino-3-nitroanisole m-Chloroaniline hydrochloride 2,5-Dichloroaniline

Fast Bordeaux G P Fast Orange GC Fast Scarlet GG

1

optimum diazo salt in relation to sensitivity and color stability, analytical procedures have been developed for 24 of these compounds.

Stabilized Diazonium Salts Used

4-Amino-2’-3-dimethylazobenzene

4-Nitro-o-anisidine o-Nitroaniline m-ru’itroaniline 4-Amino-3-nitrotoluene 4-Chloro-2-nitroaniline 5-Chloro-o-snisidine hydrochloride

5

6 7 8 9 10 11 13

Fast Red 3GL Fast Red R C Fast Red TR Fast Scarlet R Fast Blue 2B Fast Red KB Fast Red F R

20

32 33

36 37 38

Fast Fast Fast Fast Fast

39

Fast Corinth V

41

Fast Violet B

42

Fast Red LTR

44

Fast Yellow GC Fast Blue B

34 35

4s

2-.4mino-5-chlorotoluene

2-,4mino-4-nitroanisole 4’-Amino-2’,5’, diethoxy benznnilide 5-Chloro-o-toluidine hydrochloride 5-Chloro-2 (p-chlorophenoxy) aniline hydrocahloride 2-Amino-3-nitrutoluene 4-Amino-4’-methoxy diphenylamine a-Amino anthraquinone p-h’itroaniline 4-Amino-2,5-dimethoxy-4’-nitroazobenzene 4-Amin0-2~5-dimethyl-5-methoxy2‘-nitroazobenzene 4 ’-Amino-methyl-m-benzaniside hvdrochloride h’ ’,X ’-diethyl-4-methoxy-metanilamide o-Chloroaniline o-Dianisidine

Red RL Blue VB Red AL Red GG Black K

a!l other measurements were made on a SP500 spectrophotometer. Cells with 1-em. path lengths were used throughout. Both instruments are manufactured b y Unicam, Cambridge, England. Reagents. T h e diazo salts mere obtained from Imperial Chemical Industries of Australia and S e w Zealand Ltd. They are their “Brentamine” salts which are water soluble powders, stable a t room temperature if stored in t h e dark. Their aqueous solutions, however, are unstable and should he prepared fresh daily and stored in a refrigerator. Table I lists t h e salts used for this investigation; i t includes the diazo component numbmfrom thef3.D.C. Colour Index (I). Buffer solutions, pH 4 - 0.0511 potassium hydrogen phthalate; pH 7 - 2 N ammonium acetate; pH 0 0.05.U qodium borate; pH 12.8 - 2111 sodium carbonate. Qualitative Tests. Thirty-six aromatic amines and phenolic compounds ~~~~

Table

II.

Analytical Data

Molar

Diazo comoonent Compound Phenol o-Cresol m-Cresol Guaiacol Resorcinol Pvrocatechnl Pyrogallol Gallic acid a-Yaphthol p-Saphthol o-Chlorophenol I-Chloro-2naphthol Dimethylaniline +Toluidine m-Toluidine Tolvlene-2-4diamine Diphenylamine m-Phenylene diamine a-Ynphthylamine o-Chloroaniline m-Chloroaniline

Solvent Water Methyl cellosolve Itrater Water Water Water Methyl cellosolve Water Methyl cellosolve Methyl cellosolve Water Methvlceliosolve Methyl cellosolve Methyl cellosolve hlethvl celiosolve Water Methyl cellosolve Methyl cellosolve Methyl cellosolve Methyl cellosolve Alethy1 cellosolve Water

Bnffer

Ll*x

0.2ri

9

so. 37 6

9 9

37 37

0.25

37 37

0.5 0.2.5

PH 9

12.8

12.8 9

34

0.25

0

ANALYTICAL CHEMISTRY

mp. 493 476 48 I 51 9

E

tivity 10-3 17.9 11.3

x

9.2

0.1

420 439

24.8 33.0 27.5 4 .7

0.1

457

Concn. range, r g . (in 5 ml. of solvent) 1-25

2-50 2-50 1-25 0.5-20

Blank absorbance 0 ,0.5 0.09 0.05 0.02

Stabilitv in minuces Stand Read within for 60 0 0

10

5 5

30 10

0.08 0.10

30

0.40

0 0 0

5-1 00

1-50

0 .OR 0.07

15 0

15 60

1-20

5-100

5 60

9

34

0.5 0.5

4.53 600

21.6

0

48

0.5

538

17.3

2-50

0.10

0

60

9 9

37 20

0.5 0.1

479 528

19.4 16.0

1-50

0.05 0.20

0

30

2-50

60

60

r

2

0.5

430

1.6

30-1000

0.10

0

20

4

-

37

0.1

400

20.3

1-25

0.25

0

30

I

5

0.25

471

5.4

5-1 00

0.35

5

60

4

13

0 .5

450

22 .o

1-25

0.01

10

60

4

37

0.5

463

5.1

10-200

0.25

60

30

9

48

0 . -5

543

73 . O

0.5-10

0.15

10

10

7

3

0 . *5

490

17.2

2-50

0.10

0

10

9

37

0.5

500

3.2

10-200

0.20

0

GO

4

37

0.25

400

10.0

2-50

0.35

10

10

4

8

9 0 . -5 4 Sulfanilic acid Metol (methyl TVater 1 x7 0 .5 amino phenol sulfate) Tannic acid 0.5 Water 4 9 a For this calculation the molecular weight of tannic arid was taken as

900

absorp-

9.3

17.2

5-1 00 5-100

0.08 0.03

15 0

1.5

400 45.5

10,l‘

10-200

0.05

30

30

405

322.

0.6

)

Table 111.

Colors Formed b y Diazonium Salts with Phenols 1-

Diazo cwmp.

num-

)l1-

3 1

G

0

1y lY

13’

1 Y

0

0

l o

. ” .

10

1Y l o l p

0

0

0

l o

0

0

l r

l o

l o r-o r

s r

P’

s pr

0

Pr

0

l o s r

l o

Y 0

8

13’

l o l o s r

9 10

11 1a

33 34

42

44

s r

1s’

lY

l o s r

?‘

1Y

Y

0

s r l o 0

s o l o 10 10

l o 0

s r 13’ s r l o s r

1 l h 10

10

0

s r

0

0

l o

0

s r 10 r

0

r

\r

l r

1Y

0

0

0

0

1 1 v

...

10 l o l o 1 0 r-br r-br

br br 1 Lr 1 br r-br r-br r-br r-br br br

0 0

IY

Y

Y

0

0

0

0

0

1Y

l o

1 Y

s r l o

0

0

0

13’ Y 1 )‘ 10

13‘ hr

0

o 1 7’ 15

I?. I?.

Y

... s r r s r

lr

br

s3‘

1

Y 1s

...

...

s r

l r s r

r

...

r

PI’

l o

r- Jr

0

1 Y

Y

Y

0

0

0

lY

1 v

1 Y

0

0

0

0

0

r

r

r

10

l o l o

13’

l o

...

1 br

s pr s

r-br

s pr 1 lir hr o r l o 0

r-br r

3’

>-

br

0

l?.

3.

0

l v

s bl

I?. l o

0

13’

r r

v

s o

0

0

Y 0 o

s r s 0 s r-br

3’

7’

0

S Y

I 0

s r

13’

i)k ...

0

0

0

r-br s r

l y

0 0

0

Y

s r

...

...

. . ...

...

s r

0

s o s o o-r

y

... 1Y

1Y

...

r

l r y-0

... ...

...

v

1y

s y

s

1s’ l y

0

0

l o

r

0

0-br

13’

?’

0

0

s pr

s o

s o

Ir

1 0

r r

s

v

0

s r-bl

lr

l o

...

...

I

0

s r

0-r

s

s 0-r s o

v s r

Y

111

or

r-tir r-br

13’

s r s 0 s r

l o

1

Iir

s ill

s

br

...

0

S 0

1 ph br s br

S Y

1 0-3’

s r s r s r

1. 1 3‘ i o 0

s r

1 Y

13’ I,.

0

Is’ s’

I r

1 1

l o l o s pr r

l v s o r s r

s s

Pr 1 pk

0

0

0

Y

l’r

I)r 1 br 1 I)r

0

0

0

s o 1 pli r

... lY

r r-br

1).

1”’

1y 3’

r l r

I!.

0

s y

0

i0

3’

2-

naphthol

1 s

v

V

Y

Chloro-

10 10

1

l)r

10

r r

v

l y 19 1.

br 1 br 1 br hr s br 1 br 1 br

r s r s I1 s 0

0

0

pr

t)r

0

IS 10

1

hr

1s’

...

acid

r-br r-br

...

...

Gallir

1 1 l 1 1

1). 1 br

0 0

I r

10

Y

...

48

1Y

0

13’ l o

s o

3 I)

3’

13’

?‘

37

l o

s

l o s o

10

0

l o

2

111,

Ijcsor- Pyro- Pyrocinul catechol gallol

7)-

Cresol

ber 1

P0PSauh- S n u h - Chloro Chloro t1l;l th;l phenol phenul cy-

1 7

s 131

l’r

S Y

l o

I Y

...

1 br

...

0

s pr

I r

1 hr

o-r

l Y Y

... ...

l?. BY 1 pk s r

...

s o

s pr

s pr

l o

... r

Pk

1 pk 10

...

l o o-pr 0

Pr l r

...

0-r

1 0-r 1 r-pr s r-pr

1,lue

mere each spot-tested with 1 drop of each of t h e 4 buffer solutions and 1 drop of an 0.5% aqurous solution of each “Brentamine” salt listed in Table I. One drop of alcohol (absolute) containing 5 pg. of the amine or phenol was used except t h a t water was used for metol, amidol, and sulfanilic acid. After the misture was stirred, the resulting colors were compared against the blanks and from these tests the reagents vere selected for the analytical procedure$. Reagent Selection and Concentration. K a t e r was used as t h e sampling medium unless t h e color formed was Iwor or unstnhle or t h e compounds v c r e not readily soluble; in such c : m s rr:igent grade methyl cellosolre \vas substituted. Ilowever; methyl ccllosolve limited the dixzo salt which d rc.rtain of the, such as high I i l u i h , color in-

stability, and the formation of precipitates. In a few Cases conrcntrationi as low as O.1y0were found to be 1)refc~alilc. Sampling Efficiency. Since sonic of t h e compounds will occur in t h e air :is vapor or dust, a niidpt>t impinger \vas selected as t h e sanipling device with a compromise flow of 1 liter per minute. Absorption efficiency rvaq checkrd for selected compound. only. The vapor of these compounds was set up by tn-o procedures: solid compounds were hcatcd and vaporized in a gaqtight, steel chamber (appro~imately 5.5-cubic-meters capacitj.) ; and a diffusion cell previou.1y dew3xxl ( 5 ), modified by usiiig iiiachiiied Teflon seals to avoid distortion of the diffusioii uqed for the liquid compound.. Three ~ . a p o rconctxntrations w r e set ul) for each coinl)oiintl, thc nia;iinurn bci1ip ahout 5 p.p.ni. which is generally con-idered to lie tlire.shold limit for these compounds. Samy)liiig was carried out for 2 minutes through three ini1)ingew coniiected in series. Analytical Procedure. (’li:ii,g(~ :I l~i!hl)l(~r of t h e midget iniliinger tylie witli 3 1111. of solvent. RrEcr t o ‘rx\iIc I1 f u r tlic spccilic solvent.

S:iniple a t 1 liter per niinutc for 2 minutes. Aftrr sampling draw t h e .olrent a f e n times u p the inlet tube, n ithdraw t h e sampling head, and mahe the volunie u p t o 5 nil with t h e solvent RefPr to Table I1 for t h e huffrr pH and t h e concentration of the relrvant diazo reagent in water. Add 1 nil. of the buffer to control the pH of coupling folloned by 1 ml. of the diazo reagent solution. -1dd the diazo reagent first for o-chloranilirie and pyrocatrchol h c e a more i n t e n v color iy obtaiiied. Refer also to T a l k I1 for tlir color itability; in sonic caws it iq nrcr-ary to wait for a few minute< before the color- are qufficiently stable t o bc mcaw-ed. Calibration. Prepnrc R st,intlartl phenol or amine solution t o give :i concrntr:ition of t h e nia\irnuiii .inioiint 3tated in t h e range per 5 nil. of t h e relevant solvent. Table I1 indicates both t h e range and t h e solvent. Obtain a standard curve by taking 0.0, 1.0, 2.0. 3.0, 4.0, and 5.0 ml. of t h e standard solution. iiiahirig 111) t o 5.0 ml. with t h e solvent used ant1 treating t h e solution as in t h e Procedure Read t h e solutionag,iinst t h e b l m k solution. VOL. 35, NO.

7,JUNE 1963

901

0

o m

oc m3

0 0

0 3 0

b,

0

xx

-l

- 0

x A x

' h

' C

. . .: :. . . ..

:. :.

xh 3-

x . m

'

'

X '

x : 3

-_ ,"E A h

0

x : 3

.. .. . ' .. . . ' .

'

x

x .

:

x .

x : -

'

. .

x Ah

xx

:A

.. .. .. .. . .

"

L

0-

a

L

cc

O m

m m

2 0 m m

- 3

xx

L

a 3 - 3

.^

. .

. .

.. ..

x

xx

xx

hh

x x

xx

"

Y L l i a s

.-Fa 9 l a

: :

3

902

0

ANALYTICAL CHEMISTRY

x

xx

-.X

m m

41

m

RESULTS AND Dl!jCUSSlON

The spot test resuls in Tables I11 and IV do not include E,ome compounds, buffer concentrations, and diazo reagents. Quinone and hydroquinone gave only light colors er cept under alkali conditions when the color was due mostly to the action of the buffer. Phenol colors became more intense with increasing pH; at pH 4 only a-naphthol and pyrogallol gave significant colors. On the other hand the more intense colors produced by the amines with most diazo salts were at p H 4 and 7. The diazo reagents varied in their efficiency aq color producers. Some were unsuitable: the aqueous solution of Red AL mas unstable.; the reagent blank of Black K was excessively colored; Orange R S gave only light colors; Garnet GBC, Blue 2B, Blue VB, and Violet B ga7:e strong colors only with the most reactive compounds and little with the others; Red RC, Red TR, Corinth T', and Red C T R gave little reaction with amines; Red K B gave no color. However, Red GG gave intense stable colors n-ith most compcunds and it also had a low blank. Red GL and Scarlet G G gave strong stabll: color.; with a number of compounds. Bordeaux GP, Red B, and Blue B gave strong coIors with m o d compounds but gave high blanks at alkaline pH and were slightly unstable in solution. The remaining diazo salts listed in Table I gave good, but less intense, colors. Quantitative procedures were not developed for all the cornpounds in Tables I11 and IV. Aniline and amidol (2,4-dianiino phenol hydrochloride) gave yellow colorq with absordion maxima in the ultraviolet, but b3th compounds themselves had ultraviolet absorption maxima of sensitivity approximately equal t o that obtained with the diazo reagent. Para isomers generally gave weak colors because voupling occurs mainly in this position. Generally each coniFound gave differrnt shades of color with the various diazo reagents, the 2,mines tending toward yellow and the phenols toward red. By reference to Tgtbles I11 and IV i t would be possible in some cases to differentiate the compounds or isomers which could occur qiniultaneously in air--?.g., it is possible to determine ocrew1 in the pre.ence o ' the m- and pisomers by employing Fast Red LTR a t p H 7. These tables also indicate altcrriative tlinzo reagents to use if the reagent I econimended in Table I1 is un-

Table V.

Solvent

Concn.

Phenol"

Water

o-Cresola

Methyl cellosolve

Resorcinol"

Water

a-Naphthola m-Cresolb

86 88 83

245c 101 48

70 75 68

90 95 90

Methyl cellosolve

63' 28 8

77 72 80

84 88 82

Water

48 17 5 47 18 8

94 89 97 94 90

92

80 84 86

42 25 12 74 39 15

96 92 89 93 91 89

Water

m-Chloroanilineb

Methyl cellosolve

Diphenylamineb

195c 84 21 210 94 29

Per cent Per cent recovery absorption analyzed/ 1st bubbler/ theoretical total bubblers 94 85 95 78 83 90 89 85 92

o-Chlorophenol5

Methyl cellosolve

92 90 89 87 81 86

so

85 83

Gas chamber used.

* Diffusion cell used. c

An aliquot of first bubbler solvent taken for analysis

Table VI.

Compounds Phenol

o-Cresol

m-Cresol

Guaiacol

Resorcinol

f0.19

1 .8 t0.4 30.4 50.4

f O .43 f0.49 10.54 f0.76 10.36 f0.94 f1.48 f0.80 10.17 f0.24 50.13

1 .S 19.5 39.4 49.9

0.96 9.4 19.5 24.4 0.5

3.9

1 .o

7.9

12.0 20.0

Pyrogallol

Gallic acid

Standard deviation

1.05 10.0 19.8 25.1

20.2 Pyrocatccliol

Precision and Accuracy

Concn. pg. per 5 ml.

I 1 .R

available. I n developing the analytical technique, the diazo reagents giving the most intense colors were not neceqsarily used. Other factors such as color stability influenced the choice; umally when the absorption peaks approa:h or are above

Sampling Recovery and Efficiency

fO.17 10.26 f 0 .27

f0.32

Relative std . dev. 17.0 1.7 1.1 1.1

10

4.8 3.8 1.6

17.0 2.6

0.7 1.3

10.8

4.3 20.5 38.2 100

10.87 *I .70

412.25

+0.11

11.71

0.4

20.0

10.11 10.28 10.23 10.34

12.43

5.0 0.0 1.o

10

16.0

f0.44 fl.02

%

24 .o 4.7 1.8 1.5

ztO.08 10.20 f0.38 f0.20

5.5 39 .s 79.7 1oo.ri

Relative error,

5.1

3.0 0 .9n 3.5 2.0

1.7 7.9 2.6

2.8 2.4 20.4

4 .O 1.3 0.9

2.5 1.5 0.2

4.0 6.4 2.5 2.4 4 .O 2.5 0.8 1.o

1 .o 0.8

0.3 0.0

10 0.5

0.4

0 . F, 6 .5

2.6 4.7 0.3 0.0 1.7 (Continued on page 904) 8.3

VOL. 35, NO. 7, JUNE 1963

983

500 mp the colors (and blank colors) are reasonably stable. Table V reports the efficiency of sampling recovery and absorption. When the concentration was set up in the gas chamber, it was essential to

Table

Compounds a-Naphthol

VI.

Precision and Accuracy (Continued)

20.0 40.0

10.41

Relative st.d. dev. 3.4 2.1

49.9

10.29 ztl.11

0.7 2.2

2.0 20.1

10.20 10.74 10.54

9.6 3.7 1.8 1.9 35.6 3.1 1.6 1.9 12.9

Concn. p g . per 5 ml. 1.2

29.8 50.4 o-Chlorophenol

1-Chloro-2-naphthol

Dime thylaniline

+Toluidine

0.98

19.6 39.5 50.3 1.9 19.9 39.9

I1il)lienylaminc

vi-Phenylenediamine

a-Kaphthylamine

o-Chloroaniline

Sulfanilic arid

bfetol

Tannic arid

904

zt0.97 zt0.35 fO.61 +0.63

10.95 10.25

% 16 0.10 0.10 0.16 1 .o 0.6

0.5 0.8 2 .o 2.0 1.3

49.7

3. 3 0.3 1.4

30.4

zt4.03

13.3 2 .9 0.6 0.2

I .?J 2 .9 0,6 0.2

12.G

0.0 I .0 0.5

378.8 603 1002 I .0 9.9

5.2 38.0 80.0 99.8 1.04 10.1 20.1 2.5. 2 10.0 40.0 161 207 0.51 3.98 6.0 10.0 1.98 9 .92 30.0 49.7 9 .8 79.6 161

201 7,i-Chloroanilinc

10.20

Relative error,

f0.66 11.16 10.i0

19.9

Tolylene-2-Cdiamine

Standard deviation

0.5 q5.0 0.4 0.4 0.6

25 .o

171-Toluidine

sample as soon as possible, because of the rapid decay of the concentration; in these cases although the recovery was low the sampling procedure is considered satisfactory as the first bubbler absorbs at least S070 of the vapor absorbed in

2.0 20.0 39.8 51 . 0 5.0 19.4 60.4 99 . 8 4.8 39.2 79.4 100 I0 7x 120 204

ANALYTICAL CHEMISTRY

f 1 1 .o 13.36 120.5

fO.13 10.29 10.10 i-0.52 dzo.51 10.63 f2.10

1 1 .94 10.22 i-0.22

10.46 1 0 .33 f2.83 10.48 1 3 .95 1 4 .i 4 10.12 10.07 10.12

fO.19

&0.31 zt0.54 1 0 ,,51 f0.82 fO.98 13.20 1 3 .no 1 5 .GO 10.18 1O.i.5

i-0.40

2.0 0.5 2.1 9.8 1.7 2.6 1. 9 20.7 2.2 2.3

1.3 28.3 1.2 2 .3 2 .:3 24.2 1 .9 2.0 1.9 lL5.5

-tical Chemistry of Industrial Poisons, Hazards, and Solvents,” 2nd ed., Interscience, XeTy York, 1949. (4) Lambert,, J . L., Cates, I-. E., ASAL. CHEV.29, 508 (19.57). ( 5 ) hIcKelvep, J. XI., Hoelscher, H. E., Ibid., 29, 123 (19.57). (6) Pearl, I. A,, McCoy, P. F., Ibid., 32, 132 (1960). ( 7 ) Zbid., p. 1407.

RECEIVED for review Sovemher 19, 1962. Accepted hIarch 11, 1963. This paper is published bv the permission of the Chief Scientist, Dept. of Supply, Australian Defence Scientific Service, Melbourne, Victoria, Australia.