CONCLUSION
ACKNOWLEDGMENT
The results of the metal uptake studies indicate that quantitative uptakes are achieved for Ag+, Hg2+, Cu2+, Sb3+, Pb2+, and Cd2+. The uptakes for Ni2+, ZnZ+, and C d + are expected to increase when columns are used since more plates will be present. Alkali metals and alkaline earths should not interfere since they are not complexed by the dithiocarbamate resin.
We wish to thank G. Dabkowski and P. Oles for their assistance in this study.
Received for review July 11, 1973. Accepted December 26, 1973.
Microdetermination of Hydrazine Salts and Certain Derivatives with N-Chlorosuccinimide M. 2 . Barakat, .M.Abou-El-Makarem, and M. Abd El-Raoof Biochemistry Department, Faculty of Medicine, Azhar University, Madina Nasr, Cairo, Egypt
Previous methods for the determination of hydrazine salts include titrimetric (I, 2 ) , colorimetric ( 3 ) , and potentiometric ( 4 ) methods. The oxidation of hydrazine has been extensively employed as the basis of techniques for its determination ( 5 - 7 ) . Of these, the titrimetric methods are the most widely used but either show certain defects (8, 9) or seem to be unreliable (5, 10). More recently, Nbromosuccinimide has been reported as a titrant for determining amounts as low as 0.5 mg of hydrazine salt or l mg of hydrazine derivative (11). The present work describes a new method for the microdetermination of amounts as low as 100 k g of hydrazine salts and certain derivatives by the use of standard Nchlorosuccinimide solution. EXPERIMENTAL Reagents. A 0.02hr solution of standard Ar-chlorosuccinimide (NCS), B.D.H., (mol wt 133.54) was freshly prepared by dissolving 133.54 mg of NCS in hot distilled water, allowing it t o cool, a n d diluting t o 100 ml with water in a volumetric flask. A fivefold dilution yields 0.004N solution. A 0.02N solution of standard -V-bromosuccinimide (NBS), B.D.H., (mol wt 178) was freshly prepared by dissolving 178 mg of NBS in hot distilled water, allowing it to cool, and diluting with water t o 100 ml in a volumetric flask. Standardization of either titrant was done iodometrically ( 1 2 ) . Action of N-Chlorosuccinimide on H y d r a z i n e Sulfate. A 1,3013-gram portion of hydrazine sulfate (0.01 mol) was dissolved in 20 ml of distilled water, and 2.6708 grams of N-chlorosuccinimide (0.02 mol) were dissolved in 200 ml of hot distilled water. The N-chlorosuccinimide solution was allowed t o cool and then was added gradually with shaking to t h e cold hydrazine sulfate solution. During t h e addition, a strong effervescence was observed because of evolution of nitrogen. T h e presence of hydrochloric acid was detected by treating 10 ml of the colorless reaction solution with nitric acid and 10'7~sil-
ver nitrate solution. A white precipitate of silver chloride was deposited and dissolved in ammonium hydroxide. T h e presence of sulfuric acid was established by treating 10 ml of the colorless solution with hydrochloric acid and 1070 barium chloride solution. A white precipitate of barium sulfate was formed. Succinimide was isolated by distilling in uucuo the remaining 200 ml of t h e colorless solution and crystallizing the solid residue from benzene. I t was identified by melting point (125 "C) and mixed melting point determinations with an authentic sample showing no depression. Stoichiometry of t h e Reaction. When t h e recommended procedure was used, hydrazine sulfate (10 t o 100 pmol), phenylhydrazine hydrochloride (10 t o 100 l m o l ) , or p-nitrophenylhydrazine (10 to 100 pmol) reacted with exactly two equivalents of N-chlorosuccinimide. Procedure. To a n accurately measured volume--e.g., 5 ml of t h e hydrazine sulfate or hydrazine derivative solution in a 100-ml stoppered Erlenmeyer flask-add a n equal volume of dilute sulfuric acid, 1 ml of 10% potassium bromide solution, and 2 drops of Methyl Red indicator solution. Titrate the mixture with standard N-chlorosuccinimide solution (0.02N or 0.004N solution) added dropwise from a microburet with shaking after each addition. When t h e red color of the indicator fades, another drop is added, a n d the titration is continued until t h e red color just disappears. T h i s is the end point a n d the volume of t h e titer is noted. A blank experiment is done simultaneously a n d the reading is subtracted from t h e titer before calculation. Calculate the hydrazine sulfate content or the hydrazine derivative content of the unknown solution from the expression as follows:
Hydrazine sulfate content (mg or p g j = 130.13 133.54 X 2 Phenylhydrazine content (mg or p g ) = 144.61 133.54 x 2 p -Nitrophenylhydrazine content (mg or p g) =
t2)
153.14 133.54 X 2
(3)
I . M .Koithoff, J. Amer. Chem. SOC..46, 2009 (1924). 8. Singh and A. Singh, Anal. Chim. Acta, 9, 22 (1953) M . G. Bapat and S. V. Tatwawadi. J. Sci. Res. Banaras Hindu
Univ., 7, 235 (1956-57). H . T. S. Britton and M . Konigestein. J. Chem. SOC.(London), 673 (1940).
Jilek and J. Brandstetr, J. Chem. Zvesti, 7, 611 (1953) P. Endroi, Magyar Kem. f o l y . , 59, 211 (1953); Chem. Abstr., 48,
A.
SO5 (1 954), B. Suseela. Ber., 88, 23 (1955). I . M . lssa and R. M. Issa, Anal. Chim. Acta, 14, 578 (1956). R. C. Paul and A. Singh, J. lndian Chem. SOC.,32, 599 (1955). R . A. Penneman and I. F. Audrieth, Anal. Chem., 20, 1058 (1948). M . 2. Barakat and M . Shaker, Analyst (London),88, 59 (1963) M 2. Barakat and M. F. A. El-Wahab, Anal. Chem., 26, 1973 (1954).
(lj
where V = volume of standard A'-chlorosuccinimide solution used in the reaction and C = concentration of ?i-chlorosuccinimide in mg or p g per 1 ml of solution.
RESULTS Each result recorded is the average of a t least two determinations. Microdetermination of Hydrazine Sulfate. A stock aqueous solution containing 0.1 gram/100 ml of hydrazine sulfate was prepared. The hydrazine sulfate content was ANALYTICAL CHEMISTRY, VOL. 46, NO. 6 , MAY 1974
777
Table I. Microdetermination of Hydrazine Sulfate by the Proposed Method Content,
Titer of 0.02N
Error,
mg
NCS, mla
Found, mg
10 9 8 7 6
15.42 13.89 12.34 10.79 9.19 7.71 6.16 4.64 3.06 1.52
10.03 9.04 8.03 7.02 5.98 5.02 4.01 3.02 1.99 0.99
5
4 3 2 1
=t%
0.30 0.44 0.38 0.29 0.33 0.40 0.25 0.67 0.50 1.00
Dilution 1 X 10 0.004N
NCSb
Pg
1000 900 800 700 600 500
400 300 200 100
7.74 6.94 6.19 5.39 4.59 3.84 3.04 2.27 1.52 0.75
llg
1007 903 805 701 597
0.70 0.33 0.63 0.14 0.50
500
...
397 295 198 98
0.75 1.67 1.00 2.00
Experimental Error. The experimental error of the proposed method does not exceed &270when determining quantities varying from 10 mg to 100 pg of hydrazine sulfate (Tables I and 11). Application of the Proposed Method. Microdetermination of Phenylhydrazine Hydrochloride. Various known volumes of phenylhydrazine hydrochloride solutions varying from 0.1 gram to 0.01 gram % were determined by the proposed method using 0.02N and 0.004N solutions of N chlorosuccinimide, respectively, as if they were unknowns. T h e results are recorded in Table 111. Microdetermination of p-Nitrophenylhydrazine. A stock aqueous solution containing 0.1 gram/100 ml of p-nitrophenylhydrazine was prepared by dissolving 0.5 gram in 10% hydrochloric acid and completing the volume with the same acid to 500 ml in a volumetric flask. Various known volumes of the stock solution were analyzed by the proposed method as if they were unknowns using 0.02N solution of N-chlorosuccinimide. The p-nitrophenylhydrazine content of a tenfold diluted solution was also determined in various known volumes as if they were unknowns using 0.004N solution of N-chlorosuccinimide; the results are recorded in Table IV.
DISCUSSION
1 ml of 0.02N N-chlorosucciniiide = 0.6507 mg of hydrazine sulfate. 1 ml of 0.004NN-chlorosuccinimide = 130.13 pg of hydrazine sulfate.
determined by the proposed method in various kno'wn volumes of the stock solution as if they were unknowns using 0.02N solution of N-chlorosuccinimide. The hydrazine sulfate content of a tenfold diluted solution was also determined in various volumes as if they were unknowns using 0.004N solution of N-chlorosuccinimide (Table I ) . Comparative Analysis of Hydrazine Sulfate by the Proposed Method and N-Bromosuccinimide Method. T h e proposed method was compared with the previous N - bromosuccinimide method (11) by determining amounts of hydrazine sulfate ranging from 10 mg to 1 mg as if they were unknowns. The results are listed in Table
11. Interfering Substances. Typical interfering ions include iodide, sulfite, and thiosulfate ions. The former ion may be eliminated as insoluble lead iodide by adding 10% lead acetate solution and filtering. The latter ions can be precipitated in the form of the corresponding insoluble barium salt and filtered.
The proposed method is established on the fact that Nchlorosuccinimide readily and quantitatively oxidizes an aqueous solution of hydrazine sulfate. It is reduced to succinimide with evolution of nitrogen and the formation of hydrogen chloride. The reaction is constructed on the basis of the data gained as is pictured below. / \NC1
+
H,N-NH,.H,SO,
CHz-CO CH, -CO 21 CH,-CO
\NH
/
+
-
2HC1
+ N2 +
H$04
The reaction proceeds quantitatively, in aqueous acid medium and in the presence of potassium bromide, at room temperature in the ratio of two molecules of N-chlorosuccinimide to one molecule of hydrazine sulfate. Effervescence because of evolution of nitrogen is notable. The presence of hydrogen chloride and sulfuric acid in the reaction mixture has been proved. Succinimide has been isolated from the reaction mixture; mp 125 "C, and confirmed by mixed melting point determination with an authentic sample showing no depression. Similarly, N-chlorosuccinimide is quantitatively and
Table 11. Comparative Analysis of Hydrazine Sulfate by the Proposed Method and Previous N-Bromosuccinimide Method N-Chlorosuccinimiden Content, mg
10
9 8 7 6 5
4 3 2 1
' 1 ml of 0.02N 770
Titer of 0.02N NCS, ml
15.49 13.89 12.32 10.79 9.19 7.69 6.15 4.63 3.06 1.52
N-Bromosuccinimidea
Error, Found, mg
+ %
10.08 9.04 8.02 7.02 5.98
0.80 0.44 0.25 0.29 0.33
5.00
... ...
4.00 3.01 1.99 0.99
0.33 0.50
1.00
Titer of 0.02N NBS, ml
15.45 13.79 12.22 10.77 9.18 7.70 6.14 4.59 3.06 1.50
N-chlorosucciniiide or 0.02N N-bromosuccinimide E 0.6507 mg of hydrazine sulfate.
ANALYTICAL CHEMISTRY, VOL. 46, NO. 6, MAY 1974
(4)
_Error,
Found, mg
10.05 8.97 7.95 7.01 5.97 5.01
4.00 2.99 1.99 0.98
1 %
0.50
0.33 0.63 0.14 0.50 0.20 ... 0.33 0.50
2.00
~
Table IV. M i c r o d e t e r m i n a t i o n of p - N i t r o p h e n y l h y d r a z i n e b y t h e Proposed M e t h o d
Table 111. M i c r o d e t e r m i n a t i o n of P h e n y l h y d r a z i n e Hydrochloride b y the Proposed M e t h o d Content, mg
10 9 8 7 6 5 4 3 2 1
Titer of 0.02N NCS, niln
Error, Found, mg
13.84 12.45 11.14 9.64 8.34 6.92 5.54 4.14 2.78 1.40
10.01 9.00 8.06 6.97 6.03 5.00 4.01 2.99 2.01 1.01
Content, mg
* %
10 9 8 7 6 5 4
0.10 . . .
0.75 0.43 0.50 ...
0.25 0.33 0.50 1.00
3
2 1
ug
0.004N"
iig
6.94 6.24 5.54 4.84 4.14 3.44 2.74 2.04 1.37 0.68
1004 902 801 700 599 497 396 295 198 98
100
13.01 11.81 10.46 9.14 7.81 6.51 5.20 3.93 2.63 1.32
Error,
Found,mg
+ %
9.96 9.04 8.01 7.00 5.98 4.98 3.98 3.01 2.01 1.01
0.40 0.44 0.13 ... 0.33 0.40 0.50 0.33 0.50 1.00
Dilution 1 X 10
Dilution 1 X 10 1000 900 800 700 600 500 400 300 200
Titer of 0.02N NCS, ml"
P6
0.40
1000
0.22 0.13
900 800 700 600 500 400 300 200
...
0.17 0.60 1.00 1.67 1.00 2.00
100
0.004N5 NCS
6.46 5.84 5.24 4.54 3.90 3.24 2.59 1.94 1.31 0.64
Pg
999 894 802 695 597 496 397 297 201 98
0.10
0.67 0.25 0.71 0.50 0.80
0.75 1.00 0.50
2.00
1 ml of 0.02N N-chlorosuccinimide = 0.7231 mg of phenylhydrazine hydrochloride. 1 ml of 0.004N N-chlorosuccinimide = 144.61 p g of phenylhydrazine hydrochloride.
a 1 ml of 0.02N N-chlorosuccinimide = 0.7657 mg of p-nitrophenylhydrazine. 1 ml of 0.004N N-chlorosuccinimide = 153.14 p g of p-nitrophenylhydrazine.
easily reduced to succinimide by phenylhydrazine hydrochloride or p-nitrophenylhydrazine a t room temperature as is shown by the following equation:
N-Chlorosuccinimide is a n effective oxidizing agent (15, 16) and thus can decolorize Methyl Red in aqueous acid medium, b u t it oxidizes hydrazine salts or derivatives preferentially. Until all the hydrazine salt or derivative prese n t has been oxidized, the red color of the indicator persists. The slightest excess. of N-chlorosuccinimide added after all the hydrazine salt or derivative has been oxidized decolorizes the Methyl Red indicator. Thus the end point is easily detected. The use of potassium bromide as a catalyst with N-bromosuccinimide has been previously reported (17 ) . Comparative analysis of hydrazine sulfate has been done by the proposed method and the previous N-bromosuccinimide method ( 1 1). N-Chlorosuccinimide simulates N-bromosuccinimide in its oxidizing action and accuracy but seems to be somewhat more sensitive. The higher sensitivity of N-chlorosuccinimide is most probably because of its lower molecular weight, since the proposed method will determine quantities as low as 100 fig of the hydrazine salt or derivative.
CH- -CO 21 'XCl / CH--CO
+
R-SH-NHI
-.-
CH, -CO 21 CH. -CO
\SH
/
+
R-KH-N\ /
(5) C1
where R may be C6H5 or OzN-C&. T h a t substitution of chlorine occurs in the hydrazine derivative a t room temperature is evidenced by the fact t h a t the reaction mixture in case of phenylhydrazine couples with P-naphthol in sodium hydroxide to form a brilliant red azo dye of
[email protected] finding can be interpreted only by loss of HC1 from phenyldichlorohydrazine and subsequent formation of phenyldiazonium chloride; otherwise coupling would not occur. The chloride ion could be detected. The reactions presented are analogous to the action of N-bromosuccinirnide on hydrazine salts and certain derivatives (13) as well as on isoniazid (14) previously reported. (13) Hugh E. Malone, "The Determination of Hydrazino-Hydrazide Groups." 1st ed., Pergamon Press, New York, N.Y., 1970, p 13. (14) M . Z. Barakat and M. Shaker, Analyst (London),91, 466 (1966).
Received for review July 5 , 1973. Accepted November 7, 1973. (15) C. A. Groband H. J. Schmid, Helv. Chim. Acta, 36, 1763 (1953). (16) C. A. Grob and H. J. Schrnid, Experientia, 5, 199 (1949). (17) M. Z. Barakat, A. S. Fayzalla, and S. T. El Aassar, Microchem. J.. 15, 10 (1970).
ANALYTICAL CHEMISTRY, VOL. 46, NO. 6, M A Y 1974
779
