ChemInform Abstract: The Thermal Instability of 2,4 and 2,6-N-Alkylamino-Disubstituted and 2-N-Alkylamino-Substituted Nitrobenzenes in Weakly Alkaline Solution: sec-Amino Effect.

ChemInform ◽  
2015 ◽  
Vol 46 (35) ◽  
pp. no-no
Author(s):  
Christopher Walczak ◽  
Thomas J. Payne ◽  
Colin B. Wade ◽  
Matthew Yonkey ◽  
Melissa Scheid ◽  
...  
Keyword(s):  
Alkaline Solution ◽  
Thermal Instability ◽  
Weakly Alkaline ◽  
Weakly Alkaline Solution

Interdigitated Array Diffusion Layer Titration of Dithiocarbamates with Electrogenerated Hypobromite

2000 ◽  
Vol 65 (6) ◽  
pp. 1029-1034 ◽  
Author(s):  
Peter Tomčík ◽  
Dušan Bustin
Keyword(s):  
Detection Limit ◽  
Diffusion Layer ◽  
Alkaline Solution ◽  
Titration Curve ◽  
Pesticide Residues ◽  
Weakly Alkaline ◽  
Real Samples ◽  
Weakly Alkaline Solution ◽  
Interdigitated Array

A simple but sensitive technique was developed for determination of dithiocarbamates. The proposed method is based on its oxidation with hypobromite under the formation of sulfate. The oxidation proceeds only in the close vicinity of interdigitated array microelectrode (IDA), the segments of which were used as working and indicator electrodes. Hypobromite was formed by disproportionation of galvanostatically generated bromine (from bromide) in weakly alkaline solution on one segment of IDA (generator). The unreacted flux of hypobromite was amperometrically detected on the second segment (collector-indicator). The hypobromite flux is influenced by dithiocarbamates present in solution, causing changes in the collector versus generator current plot (titration curve) which can be quantitatively evaluated. The sensitivity of the method is 7 795 l mol-1 μA and detection limit estimated according to the 3s criterion is 2.2 · 10-6 mol l-1. The technique was used in analysis of real samples, such as in determination of a pesticide residues in cucumber leaves.

Chromatography on Florisil in the quantitative estimation of urinary and other porphyrins.

1976 ◽  
Vol 22 (7) ◽  
pp. 1057-1061 ◽  
Author(s):  
S Schwartz ◽  
B Stephenson ◽  
D Sarkar
Keyword(s):  
Thin Layer ◽  
Alkaline Solution ◽  
Chromatographic Analysis ◽  
Aminolevulinic Acid ◽  
Quantitative Estimation ◽  
Weakly Alkaline ◽  
Florisil Column ◽  
Weakly Alkaline Solution ◽  
Thin Layer Chromatographic Analysis ◽  
Fresh Urine

Abstract We describe the use of Florisil chromatography to purify and fractionate porphyrins into uro-, copro-, and protoporphyrins before their measurement by quantitative fluorometry. Porphyrinogens in fresh urine may be rapidly oxidized to porphyrins by chloranil, or slowly in weakly alkaline solution, before the sample is applied to the Florisil column. Aliquots of the separate ammoniacal eluates may be lyophilized for additional fractionation by direct thin-layer chromatographic analysis if desired. The behavior of delta-aminolevulinic acid, porphobilinogen, and other pyrrole compounds in this system is also described.

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