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Spectrophotometric determination of periodate with the bisthiosemicarbazones of phthalimide and 1,3-indandione
MICROCHEMICAL
JOURNAL
34, 83-88 (1986)
Spectrophotometric Bisthiosemicarbazones
Determination of Periodate with the of Phthalimide and 1,34ndandione
M.CALLEJ~N MOCH~N] ANDJ. A.MuGoz Department
of Analytical
Chemistry, Faculty of Chemistry, 41012 Seville, Spain
LEYVA
University
of Seville,
Received May 23, 1984; accepted November 18, 1985 Phthalimide bisthiosemicarbazone (FT) and 1,3-indandione bisthiosemicarbazone (IDTS) have been examined in order to evaluate their usefulness as spectrophotometric reagents for periodate. FT forms a yellow oxidation product with periodate in acid medium, with maximum absorption at 410 nm; the molar absorptivity is 2.84 x IO4M-t cm-t. IDTS gives a red color in acid medium; the molar absorptivity at 520 nm is 4.8 x IO3M-t cm-t. D 1986 Academic
Press. Inc.
INTRODUCTION
Analytical studies with bisthiosemicarbazones have so far been focused essentially on their metal complexes in solutions and spectrophotometric determination of metal ions (4, 8). However, since these compounds usually show a reducing behavior, recent applications of these reagents have been based on the spectrophotometric determination of bromate, iodate, and clorate, which act as oxidant agents with 1,3-cyclohexanedione bisthiosemicarbazone monohydrochloride (13-15) and 5,5-dimethyl-1,3-cyclohexanedione bisthiosemicarbazone monohydrochloride (12). In the same way, the spectrophotometric determination of periodate with this latter reagent was carried out (3), the oxidation of phthalimide bisthiosemicarbazone with periodate was observed (9), and a catalyzed determination of Os(VII1) in the presence of ceric salts was proposed. In this paper, the reactions between IO, and the bisthiosemicarbazones of phthalimide (FT) and 1,3-indandione (IDTS) are closely studied. The results obtained establish the optimum conditions for a rapid and sensitive spectrophotometric determination of IO;. EXPERIMENTAL Apparatus. Unicam SP8000, Unicam SP800, and Unicam SP600 S2 spectrophotometers equipped with l.O-cm glass or quartz cells and a Phillips PW9408 digital pH-meter with glass-calomel electrodes were used. Reagents. All solvents and reagents were of analytical reagent grade. Bisthiosemicarbazones were obtained by methods previously described (9, 10). Stock solutions of the reagents were prepared in dimethylformamide at concentrations of 0.2% (w/v) for FT and 0.8% (w/v) for IDTS. The solutions of periodate were prepared from accurately weighed amounts of potassium periodate. Fresh dilute solutions were prepared daily in water, and protected from light. r To whom correspondence should be addressed. 83 0026-265X186$1.50 Copyright 0 1986 by Academic Press, Inc. All rights of reproduction in any form reserved.
84
CALLEJ6N
MOCH6N AND MUtiOZ LEYVA
Procedures. FT. In a 25-ml calibrated flask place a volume of solution containing 35- 150 p,g of periodate, 5 ml of glacial acetic acid, 1 ml of 1 M trichloroacetic acid, and 5 ml of 0.2% reagent solution in dimethylformamide. Dilute to the mark with distilled water and after 15 min measure the absorbance at 410 nm against a reagent blank. A calibration graph was prepared by using standard solutions of periodate treated in the same way. ZDTS. Place the sample solution containing 125-450 pg of periodate in a 25-ml standard flask. Add 10 ml of glacial acetic acid and 10 ml of 0.4% reagent solution in dimethylformamide, diluting to the mark with distilled water. After 15 min, measure the absorbance against a reagent blank at 520 nm. A calibration graph was established for 5.0-20.0 ppm of periodate. RESULTS AND DISCUSSION
Reaction of ZO; and FT. When IO; solutions and FT solutions in dimethylformamide are mixed in an acid medium, a yellow color appears; it is attributed to an oxidation product of the reagent. The maximum absorption of the spectrum of the oxidized product occurs at 410 nm (Fig. 1). This figure indicates that the reagent excess contributes to the increase in absorbance. Obviously, this can be compensated if the analysis is made against a reagent blank. The effect of the color development was studied by preparing a series of solutions with 5.0 ppm of IO; varying from pH 1 to 5. Absorbance reached a maximum and remained constant between pH 1.6 and 2.7 (Fig. 2). For the analytical procedure, a mixture of glacial acetic and trichloroacetic acid was selected because the volume of dimethylformamide added to the preparation of the solutions increased the pH by over one unit. The influence of reagent concentration was studied by following the recom-
350
400
1150
500
X(nm)
FIG. 1. Absorption spectra of the oxidation product (A) of FT with IO, vs reagent blank and (B) reagent vs water. [IO,] = 2.6 x IO-5 M; [FT] = 5.2 x 1O-4 M.
SPECTROPHOTOMETRIC
DETERMINATION
85
OF PERIODATE
Od
-I
I 1
FIG. 2. Effect
of pH (0) on IO,-FT
2
reaction,
3
PH
and (0) on IO;-IDTS
reaction.
mended procedure and developing the reaction at room temperature. The absorbance reaches a maximum constant value when between 4.5 and 7.0 ml of 0.2% reagent solution in dimethylformamide is added; therefore we selected 5.0 ml as the optimum amount. The influence of time on the formation of the yellow product at room temperature was investigated by following the recommended procedure given above but taking the spectrophotometric measurements 5, 10, 15, 30, 60, and 120 min after sample preparation. The values of the absorbance (0.555, 0.595, 0.605, 0.620, 0.638, 0.640) show that the reaction takes virtually 60 min. It was also observed that temperature had no influence on the developing reaction. The order of reagent addition was found to be immaterial. The sequence of periodate, acid, and reagent was followed for the preparation of all measured solutions. Attempts to determine the nature of the oxidation reaction were made by the continuous-variation and molar-ratio methods, which revealed that the stoichiometric ratio of periodate/reagent is 1:3. This is in agreement with results for other oxidations of bisthiosemicarbazones (4, 8, 12-15). The experiments done in order to define the nature of the reaction product gave no results worth mentioning. Determination ofperiodate with phthalimide bisthiosemicarbazone. The adherence to Beer’s law was verified between 1.Oand 6.0 ppm of periodate. The sensitivity of the determination expressed in terms of molar absorptivity at 410 nm was 2.84 x 10“ M-l cm-‘. The reproducibility of the determination under the most favorable conditions was established by carrying out 11 determinations of 4.0 ppm of IO;, which is the amount included in the minimum error interval (Ringbom’s graph). The set of absorbance values obtained was used to evaluate the precision of the method, which, expressed in terms of the relative standard deviation, was (P = 0.05) L
86
CALLEJ6N
MOCH6N AND MUtiOZ LEYVA
TABLE 1 Effects of Foreign Anions on the Determination of Periodate with FT (4.0 pg 107 ml-‘) and IDTS (15.0 pg IO;; ml-l) Maximum tolerable foreign anion/IQ ration (w/w)
Anion added FT
200 100 5 2 0.25 co.25
IDTS
ClCl@
Br-, C,Oz-, tartrate
c,op Br-
S,O: - , BrOS 107, NO:
IO;, BrOj, NO?, S,O:-
L1That ratio causing an error no greater than ? 3%.
1.20%. For the determination of 4.0 ppm of IO; by this method, the foreign anions can be tolerated at the levels given in Table 1. Reaction of IO; and ZDTS. The periodate oxidation of IDTS produces a red color. The maximum absorption of the oxidized product occurs at 520 nm (Fig. 3), indicating that it is necessary to use a reagent blank in the analytical procedure. The influence of the pH on the absorbance, for 15.0 ppm of IO;, was examined over the pH range 0.5 to 4.0 (Fig. 2). A constant absorbance was obtained between pH 1.7 and 2.5. The pH was therefore adjusted to about 2.0 with glacial acetic acid. The results obtained in the study of reagent concentration influence show that the absorbance of the red product was maximum for 4.5 and 7.5 ml of 0.8% reagent solution in dimethylformamide. Five milliliters of 0.8% (or 10 ml of 0.4%) is recommended as a suitable amount of reagent. Under these conditions (optimum
1.0 0.8 0.6 0.4
0.2
500
550
600
650
X(MI)
FIG. 3. Absorption spectra of the oxidation product (A) of IDTS with IO; vs reagent blank and (W reagent vs water. [IOr] = 7.9 x 10e5 M: [IDTS] = 6.3 x 10e3 M.
SPECTROPHOTOMETRIC
DETERMINATION
87
OF PERIODATE
TABLE 2 Comparison of Some Spectrophotometric Determinations of IQ Molar absorptivity (nm) Optimum pH (M-l cm-i)
hl&X
UV absorption 1,2-Bis(4-dimethylaminophenyl)-ethane-1,2-diol Benzhydrazide Iron(2,4,6-tri-2-pyridyl-I ,3,5triazine 2,2’-Azinodi(3-ethylbenzothiazol-6-sulfonate) Fenol + 4-aminoantipyrine Dimedone bisthiosemicarbazone monohydrochloride Phthalimide bisthiosemicarbazone 1,3Indandione bisthiosemicarbazone
210 1.2 M SO,H, 352 2.55 450 1.5 593 4.0-4.2 420 7.6 500 10.0 415 0.5-1.2 410 1.6-2.7 520 1.7-2.5
3,200 <30,000 300 37,000 8,000 7,500 17,200 28,400 4,800
Ref.
(2) (6) (5) (1) (11) (7) (3) This paper This paper
pH and reagent) about 15 rnin was sufficient for complete reaction at room temperature, and the absorbance was constant for at least 1 hr. For this reason the measurement of the absorbance was carried out at least 15 min after reagent addition. From experiments in which the addition order was varied in all ways possible, it was concluded that the most suitable order is periodate, acid, reagent. The periodate/reagent ratio was determined using the continuous-variation and molar-ratio methods. In both instances, the molar ratio was 1: 1, but the continuous-variation method gave a 1:3 ratio (periodate/reagent). Determination of periodate with 1,3-indandione bisthiosemicarbazone. The IO;-IDTS system obeys Beer’s law over the periodate range 5.0-20.0 ppm and the molar absorptivity is 4.80 x lo3 M-* cm-i at 520 nm. The precision of the method was checked by measuring the absorbance of 11 samples, each with the IO; concentration of 15.0 ppm. The method gave a relative standard deviation (P = 0.05) of 50.8%. The effect of several anions on the determination of 15.0 ppm of IO; is shown in Table 1. Comparison with other reagents for periodate determination. Several organic reagents have been proposed for the determination of periodate. The main spectrophotometric methods proposed are summarized in Table 2. As can be seen, the determination of periodate with FT, proposed in the present work, is comparable to the most sensitive ones and the procedure recommended surpasses many others because of its rapidity and ease. REFERENCES 1. Avigad, G., Rapid sensitive determination of periodate. Carbohydrate Res. 11, I19- 123 (1969). 2. Bhattacharyya, S. N., and Chetia, P. K., Spectrophotometric determination of periodate in presence of iodate using aluminium hydroxide. Anal. Chem. 39, 369-370 (1967). 3. Callejon Mochon, M., and Mutioz Leyva, J. A., Spectrophotometric determination of periodate and glycerol with 5,5-dimethyl-l,3-cyclohexanedione bisthiosemicarbazone monohydrochloride. Anal. Chim. Actn 140, 271-280 (1982). 4. Cano Pavon, J. M., Perez-Bendito, D., and Valcarcel M., Aplicaciones analiticas de las tiosemicarbazonas y compuestos relacionados. Revision critica. Quim. Anal. 1(1982), 118-135. 5. Escarrilla, A. M., Maloney, P. F., and Maloney, P. M., Calorimetric determination of periodate with benzhydrazide. Anal. Chim. Acra 45, 199-201 (1969).
88
CALLEJ6N
MOCHGN AND MUNOZ LEYVA
6. Fields, R., and Dixon, H. B. F., A spectrophotometric method for the microdetermination of periodate. Biochem. J. 108, 883-887 (1968). 7. Gallati, H., Perjodat-bestimmung: Einfache, kolorimetrische methode mit hoher empfindlichkeit und selektivitat. Anal. Chim. Acta 96, 311-317 (1978). 8. Garg, B. S., Singh, R. B., and Singh, R. P., Analytical applications of thiosemicarbazones (TX) and semicarbazones (SC): A review. Talanta 25, 619-632 (1978). 9. Guzman Chozas, M., Perez-Bendito, D., and Pino Perez, F., Spectrophotometric determination of osmium with phthalimide dithiosemicarbazone by means of complex formation and catalytic reactions. Anal. Chim. Acta 83, 259-266 (1976). 10. Grinsteins, V., and Veveris, A., Monoguanylhydrazones and some mixed guanylhydrazonesthiosemicarbazones of B-diketones which have tuberculostatic action. Zh. Obshch. Khim. 32, 1077-1084 (1962). 11. Mahuzier, G., Kirkacharian, B. S., and Harfouche-Obeika, C., Microdosage colorimetrique de l’acide periodique par l’acide 2,2’-azino-di(3-ethylbenzothiazole-6-sulfonique). Anal. Chim. Acta 76, 79-83 (1975). 12. Moreno Diaz de la Riva, N., Ph. D. Thesis, University of Extremadura, Badajoz, 1982. 13. Roman Ceba, M., Mutioz Leyva, J. A., and Berzas Nevado, J. J., Aplicaciones analiticas de1
monoclorhidrato de la 1,3-ciclohexanodiona ditiosemicarbazona coma reactive de oxidantes. II. Determinaci6n espectrofotometrica de BrO,. Anal. Quim. 74, 620-624 (1978). 14. Roman Ceba, M., Mutioz Leyva, J. A., and Berzas Nevado, J. J., Aplicaciones analiticas de1 monoclorhidrato de la 1,3-ciclohexanodiona ditiosemicarbazona coma reactive de oxidantes. I. Determination espectrofotometrica de IO,. Anal. Quim. 74, 1075-1079 (1978). 15. Roman Ceba, M., Mmioz Leyva, J. A., and Berzas Nevado, J. J., Cyclohexane-1,3-dione bisthiosemicarbazone monohydrochloride as a spectrophotometric reagent for the rapid determination of chlorate in perchloric acid medium. Analysr 103, 963-967 (1978).
JOURNAL
34, 83-88 (1986)
Spectrophotometric Bisthiosemicarbazones
Determination of Periodate with the of Phthalimide and 1,34ndandione
M.CALLEJ~N MOCH~N] ANDJ. A.MuGoz Department
of Analytical
Chemistry, Faculty of Chemistry, 41012 Seville, Spain
LEYVA
University
of Seville,
Received May 23, 1984; accepted November 18, 1985 Phthalimide bisthiosemicarbazone (FT) and 1,3-indandione bisthiosemicarbazone (IDTS) have been examined in order to evaluate their usefulness as spectrophotometric reagents for periodate. FT forms a yellow oxidation product with periodate in acid medium, with maximum absorption at 410 nm; the molar absorptivity is 2.84 x IO4M-t cm-t. IDTS gives a red color in acid medium; the molar absorptivity at 520 nm is 4.8 x IO3M-t cm-t. D 1986 Academic
Press. Inc.
INTRODUCTION
Analytical studies with bisthiosemicarbazones have so far been focused essentially on their metal complexes in solutions and spectrophotometric determination of metal ions (4, 8). However, since these compounds usually show a reducing behavior, recent applications of these reagents have been based on the spectrophotometric determination of bromate, iodate, and clorate, which act as oxidant agents with 1,3-cyclohexanedione bisthiosemicarbazone monohydrochloride (13-15) and 5,5-dimethyl-1,3-cyclohexanedione bisthiosemicarbazone monohydrochloride (12). In the same way, the spectrophotometric determination of periodate with this latter reagent was carried out (3), the oxidation of phthalimide bisthiosemicarbazone with periodate was observed (9), and a catalyzed determination of Os(VII1) in the presence of ceric salts was proposed. In this paper, the reactions between IO, and the bisthiosemicarbazones of phthalimide (FT) and 1,3-indandione (IDTS) are closely studied. The results obtained establish the optimum conditions for a rapid and sensitive spectrophotometric determination of IO;. EXPERIMENTAL Apparatus. Unicam SP8000, Unicam SP800, and Unicam SP600 S2 spectrophotometers equipped with l.O-cm glass or quartz cells and a Phillips PW9408 digital pH-meter with glass-calomel electrodes were used. Reagents. All solvents and reagents were of analytical reagent grade. Bisthiosemicarbazones were obtained by methods previously described (9, 10). Stock solutions of the reagents were prepared in dimethylformamide at concentrations of 0.2% (w/v) for FT and 0.8% (w/v) for IDTS. The solutions of periodate were prepared from accurately weighed amounts of potassium periodate. Fresh dilute solutions were prepared daily in water, and protected from light. r To whom correspondence should be addressed. 83 0026-265X186$1.50 Copyright 0 1986 by Academic Press, Inc. All rights of reproduction in any form reserved.
84
CALLEJ6N
MOCH6N AND MUtiOZ LEYVA
Procedures. FT. In a 25-ml calibrated flask place a volume of solution containing 35- 150 p,g of periodate, 5 ml of glacial acetic acid, 1 ml of 1 M trichloroacetic acid, and 5 ml of 0.2% reagent solution in dimethylformamide. Dilute to the mark with distilled water and after 15 min measure the absorbance at 410 nm against a reagent blank. A calibration graph was prepared by using standard solutions of periodate treated in the same way. ZDTS. Place the sample solution containing 125-450 pg of periodate in a 25-ml standard flask. Add 10 ml of glacial acetic acid and 10 ml of 0.4% reagent solution in dimethylformamide, diluting to the mark with distilled water. After 15 min, measure the absorbance against a reagent blank at 520 nm. A calibration graph was established for 5.0-20.0 ppm of periodate. RESULTS AND DISCUSSION
Reaction of ZO; and FT. When IO; solutions and FT solutions in dimethylformamide are mixed in an acid medium, a yellow color appears; it is attributed to an oxidation product of the reagent. The maximum absorption of the spectrum of the oxidized product occurs at 410 nm (Fig. 1). This figure indicates that the reagent excess contributes to the increase in absorbance. Obviously, this can be compensated if the analysis is made against a reagent blank. The effect of the color development was studied by preparing a series of solutions with 5.0 ppm of IO; varying from pH 1 to 5. Absorbance reached a maximum and remained constant between pH 1.6 and 2.7 (Fig. 2). For the analytical procedure, a mixture of glacial acetic and trichloroacetic acid was selected because the volume of dimethylformamide added to the preparation of the solutions increased the pH by over one unit. The influence of reagent concentration was studied by following the recom-
350
400
1150
500
X(nm)
FIG. 1. Absorption spectra of the oxidation product (A) of FT with IO, vs reagent blank and (B) reagent vs water. [IO,] = 2.6 x IO-5 M; [FT] = 5.2 x 1O-4 M.
SPECTROPHOTOMETRIC
DETERMINATION
85
OF PERIODATE
Od
-I
I 1
FIG. 2. Effect
of pH (0) on IO,-FT
2
reaction,
3
PH
and (0) on IO;-IDTS
reaction.
mended procedure and developing the reaction at room temperature. The absorbance reaches a maximum constant value when between 4.5 and 7.0 ml of 0.2% reagent solution in dimethylformamide is added; therefore we selected 5.0 ml as the optimum amount. The influence of time on the formation of the yellow product at room temperature was investigated by following the recommended procedure given above but taking the spectrophotometric measurements 5, 10, 15, 30, 60, and 120 min after sample preparation. The values of the absorbance (0.555, 0.595, 0.605, 0.620, 0.638, 0.640) show that the reaction takes virtually 60 min. It was also observed that temperature had no influence on the developing reaction. The order of reagent addition was found to be immaterial. The sequence of periodate, acid, and reagent was followed for the preparation of all measured solutions. Attempts to determine the nature of the oxidation reaction were made by the continuous-variation and molar-ratio methods, which revealed that the stoichiometric ratio of periodate/reagent is 1:3. This is in agreement with results for other oxidations of bisthiosemicarbazones (4, 8, 12-15). The experiments done in order to define the nature of the reaction product gave no results worth mentioning. Determination ofperiodate with phthalimide bisthiosemicarbazone. The adherence to Beer’s law was verified between 1.Oand 6.0 ppm of periodate. The sensitivity of the determination expressed in terms of molar absorptivity at 410 nm was 2.84 x 10“ M-l cm-‘. The reproducibility of the determination under the most favorable conditions was established by carrying out 11 determinations of 4.0 ppm of IO;, which is the amount included in the minimum error interval (Ringbom’s graph). The set of absorbance values obtained was used to evaluate the precision of the method, which, expressed in terms of the relative standard deviation, was (P = 0.05) L
86
CALLEJ6N
MOCH6N AND MUtiOZ LEYVA
TABLE 1 Effects of Foreign Anions on the Determination of Periodate with FT (4.0 pg 107 ml-‘) and IDTS (15.0 pg IO;; ml-l) Maximum tolerable foreign anion/IQ ration (w/w)
Anion added FT
200 100 5 2 0.25 co.25
IDTS
ClCl@
Br-, C,Oz-, tartrate
c,op Br-
S,O: - , BrOS 107, NO:
IO;, BrOj, NO?, S,O:-
L1That ratio causing an error no greater than ? 3%.
1.20%. For the determination of 4.0 ppm of IO; by this method, the foreign anions can be tolerated at the levels given in Table 1. Reaction of IO; and ZDTS. The periodate oxidation of IDTS produces a red color. The maximum absorption of the oxidized product occurs at 520 nm (Fig. 3), indicating that it is necessary to use a reagent blank in the analytical procedure. The influence of the pH on the absorbance, for 15.0 ppm of IO;, was examined over the pH range 0.5 to 4.0 (Fig. 2). A constant absorbance was obtained between pH 1.7 and 2.5. The pH was therefore adjusted to about 2.0 with glacial acetic acid. The results obtained in the study of reagent concentration influence show that the absorbance of the red product was maximum for 4.5 and 7.5 ml of 0.8% reagent solution in dimethylformamide. Five milliliters of 0.8% (or 10 ml of 0.4%) is recommended as a suitable amount of reagent. Under these conditions (optimum
1.0 0.8 0.6 0.4
0.2
500
550
600
650
X(MI)
FIG. 3. Absorption spectra of the oxidation product (A) of IDTS with IO; vs reagent blank and (W reagent vs water. [IOr] = 7.9 x 10e5 M: [IDTS] = 6.3 x 10e3 M.
SPECTROPHOTOMETRIC
DETERMINATION
87
OF PERIODATE
TABLE 2 Comparison of Some Spectrophotometric Determinations of IQ Molar absorptivity (nm) Optimum pH (M-l cm-i)
hl&X
UV absorption 1,2-Bis(4-dimethylaminophenyl)-ethane-1,2-diol Benzhydrazide Iron(2,4,6-tri-2-pyridyl-I ,3,5triazine 2,2’-Azinodi(3-ethylbenzothiazol-6-sulfonate) Fenol + 4-aminoantipyrine Dimedone bisthiosemicarbazone monohydrochloride Phthalimide bisthiosemicarbazone 1,3Indandione bisthiosemicarbazone
210 1.2 M SO,H, 352 2.55 450 1.5 593 4.0-4.2 420 7.6 500 10.0 415 0.5-1.2 410 1.6-2.7 520 1.7-2.5
3,200 <30,000 300 37,000 8,000 7,500 17,200 28,400 4,800
Ref.
(2) (6) (5) (1) (11) (7) (3) This paper This paper
pH and reagent) about 15 rnin was sufficient for complete reaction at room temperature, and the absorbance was constant for at least 1 hr. For this reason the measurement of the absorbance was carried out at least 15 min after reagent addition. From experiments in which the addition order was varied in all ways possible, it was concluded that the most suitable order is periodate, acid, reagent. The periodate/reagent ratio was determined using the continuous-variation and molar-ratio methods. In both instances, the molar ratio was 1: 1, but the continuous-variation method gave a 1:3 ratio (periodate/reagent). Determination of periodate with 1,3-indandione bisthiosemicarbazone. The IO;-IDTS system obeys Beer’s law over the periodate range 5.0-20.0 ppm and the molar absorptivity is 4.80 x lo3 M-* cm-i at 520 nm. The precision of the method was checked by measuring the absorbance of 11 samples, each with the IO; concentration of 15.0 ppm. The method gave a relative standard deviation (P = 0.05) of 50.8%. The effect of several anions on the determination of 15.0 ppm of IO; is shown in Table 1. Comparison with other reagents for periodate determination. Several organic reagents have been proposed for the determination of periodate. The main spectrophotometric methods proposed are summarized in Table 2. As can be seen, the determination of periodate with FT, proposed in the present work, is comparable to the most sensitive ones and the procedure recommended surpasses many others because of its rapidity and ease. REFERENCES 1. Avigad, G., Rapid sensitive determination of periodate. Carbohydrate Res. 11, I19- 123 (1969). 2. Bhattacharyya, S. N., and Chetia, P. K., Spectrophotometric determination of periodate in presence of iodate using aluminium hydroxide. Anal. Chem. 39, 369-370 (1967). 3. Callejon Mochon, M., and Mutioz Leyva, J. A., Spectrophotometric determination of periodate and glycerol with 5,5-dimethyl-l,3-cyclohexanedione bisthiosemicarbazone monohydrochloride. Anal. Chim. Actn 140, 271-280 (1982). 4. Cano Pavon, J. M., Perez-Bendito, D., and Valcarcel M., Aplicaciones analiticas de las tiosemicarbazonas y compuestos relacionados. Revision critica. Quim. Anal. 1(1982), 118-135. 5. Escarrilla, A. M., Maloney, P. F., and Maloney, P. M., Calorimetric determination of periodate with benzhydrazide. Anal. Chim. Acra 45, 199-201 (1969).
88
CALLEJ6N
MOCHGN AND MUNOZ LEYVA
6. Fields, R., and Dixon, H. B. F., A spectrophotometric method for the microdetermination of periodate. Biochem. J. 108, 883-887 (1968). 7. Gallati, H., Perjodat-bestimmung: Einfache, kolorimetrische methode mit hoher empfindlichkeit und selektivitat. Anal. Chim. Acta 96, 311-317 (1978). 8. Garg, B. S., Singh, R. B., and Singh, R. P., Analytical applications of thiosemicarbazones (TX) and semicarbazones (SC): A review. Talanta 25, 619-632 (1978). 9. Guzman Chozas, M., Perez-Bendito, D., and Pino Perez, F., Spectrophotometric determination of osmium with phthalimide dithiosemicarbazone by means of complex formation and catalytic reactions. Anal. Chim. Acta 83, 259-266 (1976). 10. Grinsteins, V., and Veveris, A., Monoguanylhydrazones and some mixed guanylhydrazonesthiosemicarbazones of B-diketones which have tuberculostatic action. Zh. Obshch. Khim. 32, 1077-1084 (1962). 11. Mahuzier, G., Kirkacharian, B. S., and Harfouche-Obeika, C., Microdosage colorimetrique de l’acide periodique par l’acide 2,2’-azino-di(3-ethylbenzothiazole-6-sulfonique). Anal. Chim. Acta 76, 79-83 (1975). 12. Moreno Diaz de la Riva, N., Ph. D. Thesis, University of Extremadura, Badajoz, 1982. 13. Roman Ceba, M., Mutioz Leyva, J. A., and Berzas Nevado, J. J., Aplicaciones analiticas de1
monoclorhidrato de la 1,3-ciclohexanodiona ditiosemicarbazona coma reactive de oxidantes. II. Determinaci6n espectrofotometrica de BrO,. Anal. Quim. 74, 620-624 (1978). 14. Roman Ceba, M., Mutioz Leyva, J. A., and Berzas Nevado, J. J., Aplicaciones analiticas de1 monoclorhidrato de la 1,3-ciclohexanodiona ditiosemicarbazona coma reactive de oxidantes. I. Determination espectrofotometrica de IO,. Anal. Quim. 74, 1075-1079 (1978). 15. Roman Ceba, M., Mmioz Leyva, J. A., and Berzas Nevado, J. J., Cyclohexane-1,3-dione bisthiosemicarbazone monohydrochloride as a spectrophotometric reagent for the rapid determination of chlorate in perchloric acid medium. Analysr 103, 963-967 (1978).