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Potentiometric detection of alkaloids on paper partition chromatograms.
1960
Abstracts
Section
A 125
step occurring treating with salicylaldehyde and titrating, the first potentiometric the second representing the titration of the at the titration of dicyclohexylamine, imine formed by the reaction of cyclohexylamine with salicylaldehyde. A hydrogen electrode is used as the indicator electrode and a saturated calomel electrode as ihe comparison electrode. It has been found that the use of a calomel electrode, containing a saturated KC1 solution in methyl alcohol, which had been proposed in order to obtain sharper tension changes, has no advantage over the usual calomel electrode. ot. so. [ 40.71 ARGENTOMETRIC DETERMINATION OF THIOACETAMIDE BY POTENTIOMETRY. S. Petri and T. Lipiec. (Dept. of Inorganic and Analytical Chemistry, Academy of Medicine, L6dz, Poland.) Chemia Anal. , 4 (1959) 191.
An argentometric method for thioacetamide (AKT) determination has been developed. It consisted of the precipitation of AKT with an excess of standard solution of Ag ions, and back-titration of this excess with standard KI. It was performed in ammoniacal medium. In the absence of ammonia errors due to adsorption of Ag ions were observed, although large amounts of ammonia cause a decrease in the potential drop at the equivalence-point. A few mg of AKT were determined with an error less thank 1%. This method may be used to determine AKT in biological substances. Ad. Hu. 14041 POTENTIOMETRIC STUDIES OF SOME DIPYRIDYL COMPLEXES. P. George, G. I. H. Hanania and D. H. Irvine. (Dept. of Coll. Sci. , The University of Cambridge, Great Britain.) J. Chem. Sot. , (1959) 2548. The redox potentials of the tetracyanodipyridyl, tris-2:2’-dipyridyl and trisl:lO-phenanthroline Fe(H)-Fe(IR) octahedral complexes, as well as of the tris2~2’ -dipyridyl Ru(II) -Ru(III) complex have been measured at various ionic strengths + and temperatures. Values of AGo, AH’, and QS” for the cell reaction Mq+l l/2 H, = Mg + & have been calculated. The small entropy differences between the reduced and the oxidized forms of the complex ions are suggested to be related to the variable shielding effect of the organic groups on the central metal atom. L. Gi. r4051 POTENTIOMETRIC TITRATION OF COAL IN A NON-AQUEOUS MEDIUM. W. J. S. Pringle. (Nat. Coal Board, Coal Survey Lab., Birmingham, Great Britain.) Nature, 183 (1959) 815. n-Butylamine is used as the solvent and sodium methoxide in benzene/methanol solution as the titrant, the indicator electrode being an Sb electrode. A number of British coals have been titrated. The lower-grade coals show interesting qualitative differences, apparently indicative of changes in their structure. L. Gi. 14081 POTENTIOMETRIC DETECTION OF ALKALOIDS ON PAPER PARTITION CHROMATOGRAMS. B. Waligora. (Dept. of Physical Chemistry and Electrochemistry, Jagiellonian University, Krakow, Poland.) Roczniki Chem. , 33 (1959) 509. The potentiome tric method has been applied to the detection of common medicinai alkaloids on Paper chromatograms. Chromatograms were obtained on strips of Whatman No. 1 01‘ No. 4 filter paper in a closed glass cylinder. The dried chromatograms were sprayed with 0.1 N KC1 or water and carefully examined with the micro-element Sb/KCl (O.l)/Hg&l,,KCl (O.l)/Hg connected to a quadrant electrometer, W touching the Paper every 3 mm along the long axis of the strip. The electrode tension changes were recorded as a function of he position of he elec_
A 126
Joumzal of Electroanalytical
Chemistry
Vol. 1
trode. The results indicate the possibility of the practical application of this micro-element in the partition chromatography of alkaloids and their salts. Ad. Hu. I4971 ULTRAMICROCHEMICAL STUDY OF THE CELL SAP COMPOSITION OF PLANKTON DIATOMS. M. N. Petrikova. (V. J. Vernadse Institute of Geochemistry and Analytical Chemistry, Academy of Sciences, Moscow, U. S. S. R. ) Zhur. Anal. Khim., 14 (1959) 239. The composition of the cell sap of the Ethmodiscus diatom has been studied by determining the content of Na, Ca, Mg, K, Cl- and So:-. For the determination of chlorides by 0.01 N AgNO, solution, a potentiometric method was su gested, suitable for the titration of 1 mm3 volume containing 0.02 to 0.025 mm 8 of the 0.02 to 0.025 mm3 of the sample sample in 0.02 N HaSO,. For the determination, were transferred to the titration vessel which contained 1 mm3 of 0.02 N H,SO, obtaining thus an 0.01 N chloride solution. The titrant was added in portions of about 0.2 mma. In all cases well defined curves were obtained, the results of pararrangement deallel determinations agreeing well. The ultramicroanalytical scribed in a previous communication (J. P. Alimarin and M. N. Petrikova, Zhur. Anal. Khim. , 9 (1954) 127) was used. ot. so. 14681 POTENTIOMETRIC MEASUREMENTS OF EQUILIBRIA IN A GENERAL CHEMISTRY LABORATORY. John P. Chesick and Andrew Patterson. (Yale University, New Haven, Connecticut, U.S. A.) J. Chem. Education, 36 (1959) 496. Potentiometric experiments for the determination of the solubility product of silver chloride, the ionization constant of a silver-ammonia complex and the ioni-zation constant of acetic acid are described using relatively inexpensive equipment suitable for a freshman chemistry course. D. S. Ru.
w91
POTENTIOMETRIC STUDIES ON COPPER and C.S. Bhatnagar. (Chemical Laboratories, India. ) Anal. Chim. Acta, 20 (1959) 494.
FERROCYANIDE. Ram Sahai Saxena Government College, Kota, Rajasthan,
The formation and precipitation of copper ferrocyanide has been studied by potentiometric titrations of CuS04 and K4Fe(CN)G at various concentrations using a ferricyanide-ferrocyanide electrode; each of the reactants was alternately used as the titrant. The end-point obtained from the maximum value of dE/dC corresponds to the formation of a compound with the molecular formula KzCu3[Fe(CN)6]z. The titration curves have a regular form, a sharp break in potential occurs at the end-point and the results are accurate and reproducible. The method is simple and rapid and offers a fairly accurate means of determining Cu in solutions. The effects of ethanol and electrolytes such as NIIi NOa, (NH4)2 SOB and K2S04 on the end-point as well as on the nature of the curves were investigated. I’. Me. [4101 STABILITY OF METAL CHELATES OF S-QUINOLINOL-5-SULFONATE. C. F. Richard, R. L. Gustavson and A. E. Marteli. (Dept. of Chemistry of Clark University, Worcester, Mass. , U.S. A.) J. Am. Chcm. Sot., 81 (1959) 1033. Mit Hilfe potentiometrischer Titrationen und spektrophotometrischer Untersuchungen wurden die Gleichgewichtskonstanten der Kom lexbildunrsreaktionen B zwischen Mn2+-, N?-+-, Cu2+-, Zn”-: Mg2’-, Fe3+-, UC&6? - und Th+-Ionen mit 8-Hydroxo-Chinolin-5-Sulfonat bei 25” bcstimmt. Im einzelnen wurden die Konstanten berechnet fdr Chelate, die ein Molverhaltnis des Liganten zum MctallEin Verglcich ion, wie 1:l und 2:l und in einigen l!illcn 3:l und 4:l besassen.
Abstracts
Section
A 125
step occurring treating with salicylaldehyde and titrating, the first potentiometric the second representing the titration of the at the titration of dicyclohexylamine, imine formed by the reaction of cyclohexylamine with salicylaldehyde. A hydrogen electrode is used as the indicator electrode and a saturated calomel electrode as ihe comparison electrode. It has been found that the use of a calomel electrode, containing a saturated KC1 solution in methyl alcohol, which had been proposed in order to obtain sharper tension changes, has no advantage over the usual calomel electrode. ot. so. [ 40.71 ARGENTOMETRIC DETERMINATION OF THIOACETAMIDE BY POTENTIOMETRY. S. Petri and T. Lipiec. (Dept. of Inorganic and Analytical Chemistry, Academy of Medicine, L6dz, Poland.) Chemia Anal. , 4 (1959) 191.
An argentometric method for thioacetamide (AKT) determination has been developed. It consisted of the precipitation of AKT with an excess of standard solution of Ag ions, and back-titration of this excess with standard KI. It was performed in ammoniacal medium. In the absence of ammonia errors due to adsorption of Ag ions were observed, although large amounts of ammonia cause a decrease in the potential drop at the equivalence-point. A few mg of AKT were determined with an error less thank 1%. This method may be used to determine AKT in biological substances. Ad. Hu. 14041 POTENTIOMETRIC STUDIES OF SOME DIPYRIDYL COMPLEXES. P. George, G. I. H. Hanania and D. H. Irvine. (Dept. of Coll. Sci. , The University of Cambridge, Great Britain.) J. Chem. Sot. , (1959) 2548. The redox potentials of the tetracyanodipyridyl, tris-2:2’-dipyridyl and trisl:lO-phenanthroline Fe(H)-Fe(IR) octahedral complexes, as well as of the tris2~2’ -dipyridyl Ru(II) -Ru(III) complex have been measured at various ionic strengths + and temperatures. Values of AGo, AH’, and QS” for the cell reaction Mq+l l/2 H, = Mg + & have been calculated. The small entropy differences between the reduced and the oxidized forms of the complex ions are suggested to be related to the variable shielding effect of the organic groups on the central metal atom. L. Gi. r4051 POTENTIOMETRIC TITRATION OF COAL IN A NON-AQUEOUS MEDIUM. W. J. S. Pringle. (Nat. Coal Board, Coal Survey Lab., Birmingham, Great Britain.) Nature, 183 (1959) 815. n-Butylamine is used as the solvent and sodium methoxide in benzene/methanol solution as the titrant, the indicator electrode being an Sb electrode. A number of British coals have been titrated. The lower-grade coals show interesting qualitative differences, apparently indicative of changes in their structure. L. Gi. 14081 POTENTIOMETRIC DETECTION OF ALKALOIDS ON PAPER PARTITION CHROMATOGRAMS. B. Waligora. (Dept. of Physical Chemistry and Electrochemistry, Jagiellonian University, Krakow, Poland.) Roczniki Chem. , 33 (1959) 509. The potentiome tric method has been applied to the detection of common medicinai alkaloids on Paper chromatograms. Chromatograms were obtained on strips of Whatman No. 1 01‘ No. 4 filter paper in a closed glass cylinder. The dried chromatograms were sprayed with 0.1 N KC1 or water and carefully examined with the micro-element Sb/KCl (O.l)/Hg&l,,KCl (O.l)/Hg connected to a quadrant electrometer, W touching the Paper every 3 mm along the long axis of the strip. The electrode tension changes were recorded as a function of he position of he elec_
A 126
Joumzal of Electroanalytical
Chemistry
Vol. 1
trode. The results indicate the possibility of the practical application of this micro-element in the partition chromatography of alkaloids and their salts. Ad. Hu. I4971 ULTRAMICROCHEMICAL STUDY OF THE CELL SAP COMPOSITION OF PLANKTON DIATOMS. M. N. Petrikova. (V. J. Vernadse Institute of Geochemistry and Analytical Chemistry, Academy of Sciences, Moscow, U. S. S. R. ) Zhur. Anal. Khim., 14 (1959) 239. The composition of the cell sap of the Ethmodiscus diatom has been studied by determining the content of Na, Ca, Mg, K, Cl- and So:-. For the determination of chlorides by 0.01 N AgNO, solution, a potentiometric method was su gested, suitable for the titration of 1 mm3 volume containing 0.02 to 0.025 mm 8 of the 0.02 to 0.025 mm3 of the sample sample in 0.02 N HaSO,. For the determination, were transferred to the titration vessel which contained 1 mm3 of 0.02 N H,SO, obtaining thus an 0.01 N chloride solution. The titrant was added in portions of about 0.2 mma. In all cases well defined curves were obtained, the results of pararrangement deallel determinations agreeing well. The ultramicroanalytical scribed in a previous communication (J. P. Alimarin and M. N. Petrikova, Zhur. Anal. Khim. , 9 (1954) 127) was used. ot. so. 14681 POTENTIOMETRIC MEASUREMENTS OF EQUILIBRIA IN A GENERAL CHEMISTRY LABORATORY. John P. Chesick and Andrew Patterson. (Yale University, New Haven, Connecticut, U.S. A.) J. Chem. Education, 36 (1959) 496. Potentiometric experiments for the determination of the solubility product of silver chloride, the ionization constant of a silver-ammonia complex and the ioni-zation constant of acetic acid are described using relatively inexpensive equipment suitable for a freshman chemistry course. D. S. Ru.
w91
POTENTIOMETRIC STUDIES ON COPPER and C.S. Bhatnagar. (Chemical Laboratories, India. ) Anal. Chim. Acta, 20 (1959) 494.
FERROCYANIDE. Ram Sahai Saxena Government College, Kota, Rajasthan,
The formation and precipitation of copper ferrocyanide has been studied by potentiometric titrations of CuS04 and K4Fe(CN)G at various concentrations using a ferricyanide-ferrocyanide electrode; each of the reactants was alternately used as the titrant. The end-point obtained from the maximum value of dE/dC corresponds to the formation of a compound with the molecular formula KzCu3[Fe(CN)6]z. The titration curves have a regular form, a sharp break in potential occurs at the end-point and the results are accurate and reproducible. The method is simple and rapid and offers a fairly accurate means of determining Cu in solutions. The effects of ethanol and electrolytes such as NIIi NOa, (NH4)2 SOB and K2S04 on the end-point as well as on the nature of the curves were investigated. I’. Me. [4101 STABILITY OF METAL CHELATES OF S-QUINOLINOL-5-SULFONATE. C. F. Richard, R. L. Gustavson and A. E. Marteli. (Dept. of Chemistry of Clark University, Worcester, Mass. , U.S. A.) J. Am. Chcm. Sot., 81 (1959) 1033. Mit Hilfe potentiometrischer Titrationen und spektrophotometrischer Untersuchungen wurden die Gleichgewichtskonstanten der Kom lexbildunrsreaktionen B zwischen Mn2+-, N?-+-, Cu2+-, Zn”-: Mg2’-, Fe3+-, UC&6? - und Th+-Ionen mit 8-Hydroxo-Chinolin-5-Sulfonat bei 25” bcstimmt. Im einzelnen wurden die Konstanten berechnet fdr Chelate, die ein Molverhaltnis des Liganten zum MctallEin Verglcich ion, wie 1:l und 2:l und in einigen l!illcn 3:l und 4:l besassen.