Cyanide trace analysis, sample

Following Leuchter, Prof. James Roth, director of a chemical laboratory in Massachusetts, also took the witness stand to describe the results of his analysis of the 32 masonry samples, the origins of which had been unknown to him All samples taken from the gas chambers supposedly used for mass human extermination exhibited either no or only negligible traces of cyanide, while the sample from the delousing chambers taken for use as control purposes exhibited enormously high cyanide concentrations.27... 

The samples from the walls added during the conversion to hot air disinfestation should exhibit no cyanide residues. Accordingly, sample no. 10 from the interior wall incorporated at a later time exhibits only a very low cyanide concentration near the detectable threshold. Sample 21 was taken from the mortar between the bricks of the wall installed later, at a depth of 1 cm to 5 cm into the masonry. There is a crack in the masonry of the interior wall at this location. The analysis shows minimal but hardly interpretable traces of cyanide below the detectable threshold in this interior wall as well. This finding may indicate disinfestation of these rooms after the conversion to hot disinfestation, if the slight quantities have not in any case lost all probative value, like the control analysis of the other samples have shown. 

Finally, the Auschwitz State Museum itself ordered an expert report to be compiled. The Institute for Forensic Research, Toxicology Division, of Cracow, Poland, named after Prof. Dr. Jan Sehn, prepared this report under Prof. Dr. J. Markiewicz on September 24, 1990, which confined itself to the analysis of masonry samples.56 The report concluded that the reason why Leuchter s samples from the homicidal gas chambers were mostly negative with respect to traces of cyanide was because the cyanide compounds had been exposed for more than 40 years to weathering, which these compounds allegedly could not have withstood. Three of these authors from the Jan Sehn Institute later published additional findings,57 which were, however, based on a veri-fiably incorrect analytical method—as was the first series of analy-... 

Trace amounts of cyanide are usually determined by flow injection spectrophotometric procedures. The target species is first halogenated with chlora-mine-T, after which it reacts with a mixture of pyrazolone or barbituric acid and isonicotinic acid or pyridine to form a bluish-violet polymethine dye. The implementation of gas-diffusion modules in the flow setup for hydrogen cyanide separation avoids matrix interferences and enables the adaptation of inherently nonselective detectors, such as metallic silver-wire electrodes for potentiometric measurements. Total inorganic cyanide, including free and complexed species, such as iron-cyanide complexes, may be determined by sample decomposition with UV irradiation and further photometric or amperometric analysis. 

---