Arsenic analysis, conducting

In all 28 parameters were individually mapped alkalinity, aluminum, antimony, arsenic, barium, boron, bromide, cadmium, calcium, chloride, chromium, conductivity, copper, fluoride, hardness, iron, lead, magnesium, manganese, nitrate, pH, potassium, selenium, sodium, sulphate, thallium, uranium, and zinc. These parameters constitute the standard inorganic analysis conducted at the DENV Analytical Services Laboratory. 

Water sample collection procedures used in this study are outlined by Koterba et al. (1995). Field measurements included temperature, dissolved oxygen, pH, specific conductance, redox potential, alkalinity, and field tests for total and ferrous iron, nitrate, ammonia, sulfate, sulfide, turbidity, and phosphate (Haack and Trecanni, 2000). Samples collected for trace-element analysis were filtered to pass 0.45 pm. Samples for arsenic analysis included sub-samples for total and filtered arsenic, arsenate, and arsenite (Kim, 1999). 

Samples Analyzed by Inductively Coupled Plasma (ICP) Metals — Where two or more of the following analytes are requested on the same filter, an ICP analysis may be conducted. However, the Industrial Hygienist should specify the metals of interest in the event samples cannot be analyzed by the ICP method. A computer print-out of the following 13 analytes may be typically reported Antimony, Beryllium, Cadmium, Chromium, Cobalt, Copper, Iron, Lead, Manganese, Molybdenum, Nickel, Vanadium, Zinc. Arsenic — Lead, cadmium, copper, and iron can be analyzed on the same filter with arsenic. 

In a historical cohort mortality study of 1,990 primary lead smelter workers, an SMR of 2.04 for mortality from renal cancer was calculated (Selevan et al. 1985). The cohort consisted of workers who had worked at least 1 year, with at least 1 day of employment at the smelter between 1940 and 1965. The cohort had been heavily exposed to lead and in 1976 the PbB levels averaged 56.3 pg/dL. Exposures to cadmium and arsenic were generally minor. A follow-up study of this cohort was conducted from 1977 through 1988 (Steenland et al. 1992). Analysis of the follow-up study revealed an excess of kidney cancer, particularly in the high-lead group (SMR 2.39). Although, as the authors indicate, the study is... 

HTA-3, Analytical Procedures. Accdg to Pris-tera (Ref), up to 0.35% of Ca silicate may be used as an additive. The analysis of HTA—3 may be conducted as follows TNT is extracted with CC14 HMX is extracted with acetone the residue is Al. If Ca silicate is present, the residue is treated with 10% NaOH soln and washed with water, the remainder is Ca silicide Ref Frank Pristera (Picatinny Arsenal), Explosives , in Vol 12, p 449 of Encyclopedia of Industrial Chemical Analysis , J. Wiley, NY (1971)... 

Gradually a tremendous arsenal of processes has been developed, allowing the analyst to respond to an increasing number of diverse demands. Furthermore, the study of modern chemical analysis techniques is far removed from traditional descriptive chemistry. Many analyses are conducted in non-specialised environments, either on site or at simple workbenches. The determination of compounds is currently quite remote from the use of chemical reactions, which are often avoided for many reasons. Former wet chemistry methods, at the origin of the term analytical chemistry, have become less important because they lack sensitivity, are lengthy and their precision can too easily be altered by the use of insufficiently pure reagents. Nonetheless, wet chemistry methods are still interesting to study. 

In 1982, Soga et al. 256> showed that exposure of acetylene to AsFs at low temperatures leads to rapid polymerization (in our experience this reaction can be explosively violent). The product is a solid polymer which is heavily arsenic-doped and has a conductivity several orders of magnitude lower than a conventional sample of polyacetylene saturation-doped from the gas phase. Aldissi and Liepins 2S7) have adapted this reaction to the preparation of soluble polyacetylene by adopting AsF3 as the reaction solvent. They claim that polymerization of acetylene with AsF5 is very rapid, giving a polymer which is soluble in common solvents. However, elemental analysis shows that the polyacetylene formed contains about one As atom per 10 CH units and this is not removed on repeated reprecipitations. It seems likely that the As atoms form part of the chain backbone, conferring sufficient flexibility to allow dissolution. It is claimed that films of soluble polyacetylene can be doped but very little information has been published. 

Prest, J.E., Baldock, SJ., Fielden, P.R., Goddard, N.J., Brown, B.J.T., Miniaturised isotachophoretic analysis of inorganic arsenic speciation using a planar polymer chip with integrated conductivity detection. J. Chromatogr. A 2003,990, 325-334. 

Conductivity detection performed with a contactless conductivity detector through the packed bed was shown to be a more versatile and sensitive method than indirect UV detection [77]. Chen et al. employed inductively couple plasma mass spectrometry (ICP MS) as a detection tool for the simultaneous analysis of various ionic species of arsenic, chromium, and selenium [79]. The separation was achieved on an OT CEC column prepared by bonding a macrocyclic polyamine medium on the walls of the capillary. 

Occasionally, the extraction of arsenic forms can be conducted using demineralized water, but only in cases involving the release of stable compounds in solutions of varying pH. It has been employed, for example, in comparative analysis of the hair of 1000-year-old mummies recovered from the Atacama Desert in Chile, and in analyses of hair collected from contemporary residents of India inhabiting areas contaminated with arsenic [92]. Similar contents of dimethylarsinic acid [DMA(V)] and monomethylarsonic acid [MMA(V)] were found in both materials under study. 

The Trace Metals Project conducted a study to identify the type of container which would provide minimum losses of arsenic and mercury by precipitation, volatilization, adsorption, or diffusion. Solutions of organomercury and organoarsenic compounds added to petroleum feedstock were used. Because of the relative ease with which mercury and arsenic can be determined at sub-parts-per-million levels in a hydrocarbon matrix by instrumental neutron activation analysis (INAA), this technique was used for the analytical measurements. The solutions were stored in five different types of glass and/or plastic containers and sampled periodically over eight months (12). The results of the study are summarized in Tables 2.III and 2.IV. 

It will rarely happen that in a case of suspected homicidal poisoning by arsenic, or by other poisons, the physician in charge will be willing or competent to conduct the chemical analysis, upon which, probably, the conviction or acquittal of the accused will mainly depend. Upon his knowledge and care, however, the success or futility of the chemist s labors depends in a great measure. 

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