Comparison of cyanide content in arbila beans (Phaseolus lunatus l) of East Nusa Tenggara using picrate and acid hydrolysis methods

Arbila beans contains cyanogenic compounds in the form of linamarin (cyanoglucosides), acetone cyanohydrin, and free cyanide, all together constitute total cyanide content. The objective of this study was to compare the cyanide content in arbila beans analyzed by picrate and acid hydrolysis methods. Picrate method measures total cyanide only. Cyanide content was identified by using a picrate paper, which turned into yellow. The absorbance was measured by a spectrophotometer at 510 nm. Acid hydrolysis method measures cyanide in arbila beans in the form of linamarin, acetone cyanohydrin, and free cyanide. Linamarin wa hydrolyzed in H3PO4 solution. Estimated cyanide levels was measured by using a colorimetric procedure. Data was analyzed using Independent sample t-test (SPSS v.16). The results showed that, there was no difference in the total level of cyanide in both methods. Total cyanide measured by picrate and acid hydrolysis method was 2705.17 ppm and 2693.29 ppm, respectively. In addition, the three forms of cyanide content were as follows: linamarin 926.22 ppm, cyanohydrin 556.01 ppm, and free cyanide 1211.06 ppm. Based on the results, both methods can be used for total cyanide analysis. To determine the form of cyanide other than total cyanide, it is recommended to use the acid hydrolysis method.

Opportunity of objective account of the colorimetric procedure using benzidine indicative at establishing the preliminary presence of blood on the material evidences

The article presents a modification of the colorimetric method for the preliminary establishment of presence of blood in the stainson the material evidences using benzidine test. The proposed modification is accompanied by photometric accounting and computer processing of the results. Performance, objectivity, as well as other features and advantages of this method when used in forensic practice are described in detail.

A Spectrophotometric Flow Injection Method for Determination of Ultratrace Amounts of Phenylhydrazine by Its Inhibition Effect on the Reaction of Thionin and Nitrite

A simple flow injection colorimetric procedure for determining phenylhydrazine was established. It is based on the reaction of phenylhydrazine in sulfuric acid with thionin and sodium nitrite. Reaction was monitored spectrophotometrically by measuring thionin absorbance atλmax=602 nm. A standard or sample solution was injected into the sulfuric acid stream, which was then merged with sodium nitrite stream and thionin stream. Optimum conditions for determining phenylhydrazine were investigated by univariate method. Under the optimum conditions, a linear calibration graph was obtained over the range 0.05–0.60 μmol L−1, and the detection limit was 0.027 μmol L−1(s/n=3). The proposed method has been satisfactorily applied to the determination of phenylhydrazine in human serum and water samples.