Cyanide analytical methods

Analytical Methods for Determining Cyanide in Biological Samples... 

Analytical Methods for Determining Environmental Degradation Products of Cyanide... 

The purpose of this chapter is to describe the analytical methods that are available for detecting and/or measuring and monitoring cyanide in environmental media and in biological samples. The intent is not to provide an exhaustive list of analytical methods that could be used to detect and quantify cyanide. Rather, the intention is to identify well-established methods that are used as the standard methods of analysis. Many of the analytical methods used to detect cyanide in environmental samples are the methods approved by federal organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). Additionally, analytical methods are included that refine previously used methods to obtain lower detection limits, and/or to improve accuracy and precision. 

Methods for Determining Biomarkers of Exposure and Effect. Besides environmental exposure, exposure to cyanide can also occur from consumption of cyanide-containing food, metabolism of certain drugs, and smoking cigarettes. Since so many factors can influence cyanide exposure, the exact correlation between cyanide concentrations in the body and its level in the environment has not been made. Therefore, measuring cyanide and/or thiocyanate levels in blood and urine cannot be used as a biomarker for exposure to low cyanide concentrations. Analytical methods of required sensitivity and reliability to detect cyanide and thiocyanate in blood, plasma, and urine of both unexposed and exposed persons are available (see Table 6-1 and Table 6-3). Further studies determining biomarkers for exposure to low cyanide concentrations would be useful. 

Cyanide metabolizes in the human body to thiocyanate, and its biodegradation products include ammonia, carbon dioxide, nitrate, or nitrogen (Richards and Shieh 1989). The detection of thiocyanate in body fluids may indicate cyanide exposure. Similarly, the amounts of cyanide degradation products formed in an environmental medium could be used to measure cyanide s biodegradation rate. A summary of methods for determining environmental degradation products is shown in Table 6-4. Suitable analytical methods are available to detect all of these compounds (Pettigrew and Fell 1973 Richards and Shieh 1989). 

Table 6-4. Analytical Methods for Determining Biomarkers for Cyanide (continued)... 

NIOSH. 1989b. Hydrogen cyanide. Manual of analytical methods, 3rd edition, third supplement. National Institute of Occupational Safety and Health. Cincinnati, OH. NTIS number PB90-162470, 6010-1-6010-4. 

SDS), and indeed SDS-catalysis of Hg " -catalyzed replacement of cyanides in [Fe(C1 6]" 1 1,10-phenanthroline has been proposed as an analytical method for the determination of mercury. ... 

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-... 

In a later study, these authors published additional analysis results of samples taken later, using the same analytic method. According to these analyses, the cyanide concentration of samples taken in a disinfestation chamber and in alleged homicidal gas chambers were in the range of 0.0 to 0.8 and 0.0 to 0.6 mg/kg, respectively. This study also... 

Many people, both experts and laymen, rely good-naturedly upon the findings of the Jan Sehn Institute for Forensic Research in Cracow, i.e., the study published in 1994 by Prof. Markiewicz and colleagues. These Polish scientists, however, tested their samples with analytical methods that were unable to detect stable iron cyanide compounds. They did this because they could not imagine how such stable iron cyanide compounds could form. It is, of course, no shame to fail to... 

Other general applications have included catalyst carriers and decolorizing for gold recovery from cyanide leach solutions. Of particular interest is its effective use for military and industrial clothing where protection from noxious vapors is necessary. Recent studies have shown its ability to separate chemical isomers, such as the separation of dioxin isomers. It has been used worldwide for analytical methods for determining trace (PPB) toxic substances in water,... 

Determination of cyanide or its metabolites in biological fluids is necessary for forensic, clinical, military, research, and veterinary purposes. The choice of analytical methods depends on a variety of factors like sensitivity, specificity, rapidity, convenience, facilities, and expertise. The selection of biological sample, time of sampling, time to analyze and storage conditions, and interfering substances are other factors which influence the choice of analytical methods (Troup and Ballantyne, 1987). There are several convenient and sensitive methods for measuring cyanide in biological fluids but many of them have limitations. Some of the methods are summarized below. 

The reaction of HCN with dilute aqueous sodium hydroxide can be used to produce sodium formate, and this reaction has served as the basis for an analytical method for measuring cyanide (Doizine et al., 1982). 

Cyanide is a common industrial chemical that has many uses, and it is produced in large quantities across the world as described in Chapter 14. Synonyms for HCN include hydrogen cyanide, prussic acid, formic anamminide, and fromonitrile (Agency for Toxic Substances and Disease Registry, 1997). Analytical methods are based upon the physiochemical state of cyanide and its interaction in the body. 

Analytical Methods for Determining Cyanide in Biological Samples (Modified from Table 6.1 in ATSDR s Toxicological Profile for Cyanide)... 

Abstract. Cyanides and hydrocyanic acid are one of the priority pollutants being most toxic. Therefore, it is very important to monitor cyanide concentration with specific and sensitive analytical methods. Some analytical methods for cyanide determination were presented in the last years spectrophotometer, potentiometer with silver cyanide electrode and titrimetric method. The paper presents original results concerning the spectrometric method and argentometric titration utilization for the measurement of cyanide concentration in some distilled alcoholic drinks from plums, grapes and apricots. The obtained cyanide concentrations vary between 0.0162 and 0.0970 mg/lOOmL, being under the imposed limits. 

The analytical methods are similar to those of other nitriles. GC-FID and GC/MS techniques are suitable for its analysis. Wet methods can be applied to determine the total cyanide (-CN) contents. 

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