Tissue and Other Samples

This chapter deals with the determination of xenobiotic substances in biological materials. Although such substances can be measured in a variety of tissues, the greatest concern is their presence in human tissues and other samples of human origin. Therefore, the methods described in this chapter apply primarily to exposed human subjects. They are essentially identical to methods used on other animals, and in fact, most were developed through animal studies. Significantly different techniques may be required for plant or microbiological samples. 

It was observed that a matrix thickness between 5 and 50 im was sufficient for reasonable signal-to-noise ratio (s/n) of lipid ions in mouse brain tissue and other samples. 

Water, soil, sediment, biosoUds, tissue, and other sample matrices... 

The i.v. approach has the distinct advantage of measurements being carried out under the most physiological conditions. On the other hand, the caveats include confounding effects of peripheral metabolism, which may give rise to artifactual brain uptake of degradation products. To exclude such a possibility the application of suitable analytical techniques to tissue and plasma samples is required. 

Methods and technology were developed to analyze 1000 samples/yr of coal and other pollution-related samples. The complete trace element analysis of 20-24 samples/wk averaged 3-3.5 man-hours/sample. The computerized data reduction scheme could identify and report data on as many as 56 elements. In addition to coal, samples of fly ash, bottom ash, crude oil, fuel oil, residual oil, gasoline, jet fuel, kerosene, filtered air particulates, ore, stack scrubber water, clam tissue, crab shells, river sediment and water, and corn were analyzed. Precision of the method was 25% based on all elements reported in coal and other sample matrices. Overall accuracy was estimated at 50%. 

These studies suggest that monoclonal antibodies specific to human albumin may be produced such antibodies will be of value in determining the human origin of blood, tissue, and other body fluids. We have been successful in producing a monoclonal antibody that reacts with an epitope on serum albumin that is specific to samples of human origin. 

A previous study for the evaluation of the organochlorine pesticides burden in the human body, of a non-occupational-exposed population (WHO Project European Cooperation on Environmental Health Aspects of the Control of Chemicals ) indicated that human milk levels in the range of 11-12 mg kg HCH and 2.8 mg kg DDT, were about 5 times higher than in other European countries. The adipose tissue and fat sampled from humans, indicated a mean content in DDT plus DDE in the range of 8-17 mg kg, the DDE p entages demonstrated over a long period involving the metabolization of DDT and a constant intake of DDE in food. 

While flame AAS is adequate for routine determination of serum Fe, micro methods utilizing the furnace have been developed (Lewis et al., 1984) for pediatrics, etc. Of course, deproteinization is still required, usually with trichloroacetic acid. Because of furnace sensitivity, the serum sample is diluted 1 -i- 9 in a solution containing the matrix modifier and about 0.2% Triton X-100, and a 10-/other biological materials, once the sample is in solution. 

For the practical analysis of Ni in biological materials, GF-AAS techniques are by far the most important, and for biological fluids demand only very simple steps for sample preparation. Voltammetrio methods can provide lower detection limits in specially prepared samples, while less sensitive methods such as inductively coupled plasma-atomic emission spectrometry (ICP-AES) may be useful in multielement protocols with tissues and other solid samples. 

Sample preparation is a major challenge for any rapid screening assay procedure. It has been estimated that sample preparation can claim about 50-75% of the total analysis time, especially for tissues and other solid matrices, which require the liberation of plasma protein-bound residues. Despite this limitation, most of the technical innovations and improvements continue to be made in the detection procedures. 

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