Trace Analysis

trace analysis

[′trās ə‚nal·ə·səs]
(analytical chemistry)
Analysis of a very small quantity of material of a sample by such techniques as polarography or spectroscopy.

Trace Analysis

 

the chemical analytical determination of very small amounts of elements and compounds (less than 0.01 percent) present in the form of admixtures in the major components of the sample under study. Analyses are carried out on samples with weights from fractions of a microgram to several grams, depending on the type of material studied; the micro-constituents, or trace constituents, range in weight from 10-9 to 10-4 g. Determinations are made of trace amounts of elements and compounds in, for example, seawater, soil, city air, the air of industrial plants, metals, plant and animal cells, chemical reagents, medicines, drinking water, and food products. Trace analysis is expressed not as a percentage of weight, as is customary in quantitative analysis, but in parts per million (ppm).

Certain features and difficulties are peculiar to trace analysis. As a consequence of the marked difference in the contents of the major and minor species, a separation and preconcentration of microconstituents is almost always required in order to reach the detection limits of the species of interest. The techniques most often used for separating the trace components include those of liquid extraction, distillation and sublimation, ion exchange, chromatography, and coprecipitation. For the trace analysis proper, favored techniques include spectrophotometry in the ultraviolet and visible regions, gas chromatography, atomic absorption, neutron activation analysis, emission spectroscopy, and flame photometry. For example, in a 1–50 microliter sample, a 1 × 10-5 microgram admixture of hydrocarbon (approximately 10 ppm) may be determined with a flame-ionization detector, while an electron-capture detector will determine a hydrocarbon admixture with a concentration of approximately 0.1 ppm. Flame photometry can determine approximately 0.05 ppm Cs and K and approximately 0.01 ppm Na; neutron activation analysis can determine approximately 0.0001 ppm Al in a 10-g sample.

Trace analysis requires that reagents, water, and other solvents be carefully purified and that dust and possible chemical contaminants be removed from the laboratory atmosphere. Laboratory ware made of polyethylene is used.

Trace analysis is gaining in importance, especially in connection with the development of ecological and biochemical studies, nuclear technology, and the production of semiconductor materials.

REFERENCES

Sandell, E. Kolorimetricheskie melody opredeleniia sledov materialov. Moscow, 1964. (Translated from English.)
Rukovodstvopo analiticheskoi khimii. Moscow, 1975. (Translated from German.)

IU. A. KLIACHKO

References in periodicals archive ?
To address the increasing requirements of high purity aluminium, manufacturers are enhancing their capacities and personnel in metallurgy, application technology, metal purification, as well as trace analysis. As electronic industry significantly penetrates in other end-user industries, demand for stated electronics components is set to rise.
Method validation has a considerable importance in trace analysis and very essential to verify the accuracy and precision of the proposed method.
Rather, such information may provide a starting point for further and more detailed investigation." (Crime Gun Trace Analysis Reports, ATF, 1998).
Has high-resolution trace analysis been run on a sample of the nerve agent that revealed any evidence as to the location of its production or identity of its perpetrators?," Corbyn asked.
Analytical chemistry services are offered for, trace analysis, material and impurity identification, moisture analysis and determining chemical composition.
Higher isotope selectivity of Sr can be expected with our proposed transition, which would be useful for trace analysis of [sup.90]Sr in environmental applications.
The last chapter walks through the trace analysis of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organophosphorus compounds.
Coupled with improved long-term stability due to high amplification levels and reduced noise levels, the GCMS is ideal for analysts who require the most reliable trace analysis results, including analysis of extremely small quantities of dioxin in foods and the environment, POPs components, endocrine disrupting chemicals, impurities in pharmaceuticals, and banned drugs in hair samples.
It may be carried out in open or closed systems, the latter being especially recommended for trace analysis. The breakthrough in modern mineralization techniques came with introduction of microwave energy.
AXYS offers ultra trace analysis of persistent organic pollutants, contaminants of emerging concerns and is in the early development stages of the fast growing metabolomics business.
Examples of emergency analyses include pumping outage, reaction to contamination events, trace analysis, asset criticality, which can all be accurately and effectively simulated in WaterGEMS.