Sampling and analytical methods

A great deal of the research that has been carried out into the concentrations of O2 and CO2 in soil air has been for the purposes of agriculture. There is a large body of literature describing different sampling methods (e.g., Yamaguchi et al., 1962 Tackett, 1968 Dowdell et al., 1972 Burford and Stefanson, 1973 Bunting and Campbell, 1975). 

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The evaluation phase of industrial hygiene is the process of making measurements on some set of samples which permits a conclusion about the degrees of hazard. Before conducting an evaluation, it is necessary to make a number of choices of what and where to sample, when to sample, how long to sample, how many samples to take, what sampling and analytical methods to use, what exposure criteria to use in the analysis of the data, and how to report the results. These choices as a whole constitute the evaluation plan. The object is to find if one or more workers have an unacceptable probabiUty of being exposed in excess of some estabUshed limit. 

Sensitivity. The sampling and analytical method together should ideally have a limit of detection much less than the exposure limit. Less sensitive methods are stiU usable, however, as long as the limit is easily within the range of the method. 

Operations capable of generating airborne beryUium particulate, such as melting, machining, welding, grinding, etc, are effectively controUed by local exhaust ventilation or other control measures. To assure a safe environment and measure compliance with the OSHA standards, employee exposures should be periodicaUy measured by prescribed air sampling and analytical methods. 

How does the range of concentrations of air pollutants of concern to the industrial hygienist differ from that of concern to the air pollution specialist To what extent are air sampling and analytical methods in factories and in the ambient air the same or different ... 

The information obtained during the background search and from the source inspection will enable selection of the test procedure to be used. The choice will be based on the answers to several questions (1) What are the legal requirements For specific sources there may be only one acceptable method. (2) What range of accuracy is desirable Should the sample be collected by a procedure that is 5% accurate, or should a statistical technique be used on data from eight tests at 10% accuracy Costs of different test methods will certainly be a consideration here. (3) Which sampling and analytical methods are available that will give the required accuracy for the estimated concentration An Orsat gas analyzer with a sensitivity limit of 0.02% would not be chosen to sample carbon monoxide... 

It was observed that the factors contributing to the variation of leachate data are solid waste characteristics, for example, the composition and size of the waste and degree of compaction, the moisture content and degree of rainwater infiltration, temperature, sampling, and analytical methods.47... 

Based on this background new sampling and analytical methods have been tested in northern Finland to seek new applications for exploration by using surficial till as a sample material with emphasis on decreasing analytical costs and increasing sample efficiency. This study was carried out as a part of ongoing Au, Ni and PGE exploration project of the Geological Survey of Finland. 

Sampling and analytical methods Locations for the outlet sediment (overbank) samples are shown in Figure 1. In all, 99 catchments were sampled giving an average sample density of 1 site/1540 km2. At most sites three samples were taken (a) a top outlet sediment (TOS) from 0-10 cm depth (b) a bottom outlet sediment (BOS) from 60-90 cm depth and (c) a shallow outlet sediment (SOS) from 10-25 cm depth specifically for MMI determinations. Two size fractions (<180 pm and <75 pm) were prepared from the TOS and BOS samples. The SOS sample for multi-element MMI (MMI-M) analysis by method ME-MS17 was provided to ALS Chemex in its bulk form. 

Field pH, Munsell soil colour (dry moist), EC 1 5 (soil water), pH 1 5, XRD, laser particle size analysis, XRF (multiple elements), ICP-MS (after HNO3/HCKV HF/HCI digestion for multiple elements), ICP-MS (after HF/HCI/HNO3 digestion for Se), ISE (for F), GF-AAS (for Au), and ICP-MS after MMI extraction were performed. Full details of the sampling and analytical methods are given in Caritat Lech (2007). 

Bruland, K. W., Franks, R. P., Knauer, G. A. and Martin, J. H. (1979). Sampling and analytical methods for the determination of copper, cadmium, zinc and nickel at the nanogram per liter level in sea water, Anal. Chim. Acta, 105, 233-245. 

Detailed examples and figures throughout the text help readers successfully perform soil sampling and analytical methods as well as better understand soil s chemical characteristics. At the end of each chapter, a bibliography and list of references lead to additional resources to explore individual topics in greater depth. Each chapter also offers problem sets, encouraging readers to put their newfound skills into practice. 

The collection and evaluation of different liquid manure sampling and analytical methods to obtain comparable results. 

Soil sampling surveys are routinely used to explore for concealed mineral deposits. The giant Pebble Cu-Au-Mo porphyry deposit, located 320 km southwest of Anchorage, Alaska, provides an opportunity to test various sampling and analytical methods commonly used by the exploration community. 

OSHA, Index of Sampling and Analytical Methods (http //www.osha-slc.gov/dts/sltc/methods/ toc.html). 

In the second phase more emphasis was placed on methods development and the substances that were studied were selected from those for which validation methods were not available from the first phase. The results of these studies were presented as individual reports for each substance. They are a sampling and analytical method (SAM), a sampling data sheet (SDS), and a backup data report (BUD). The reports on methods have been published by NIOSH and are available through the U.S. Government Printing Office, Washington, D.C. 

A detailed protocol for laboratory validation of sampling and analytical methods for toxic substances in workplace environments is given in Figure 1. The literature was searched and a method of sampling and analysis was selected. The next step was to evaluate and, if necessary, develop an analytical method that was compatible with the sampling medium. If a satisfactory analytical method became available only then did we undertake generation of a test atmosphere. Then samples were collected with the appropriate collection medium. Both capacity and collection efficiency were evaluated. 

The basic criterion for successful validation was that a method should come within 25% of the "true value" at the 95% confidence level. To meet this criterion, the protocol for experimental testing and method validation was established with a firm statistical basis. A statistical protocol provided methods of data analysis that allowed the accuracy criterion to be evaluated with statistical parameters estimated from the laboratory test data. It also gave a means to evaluate precision and bias, independently and in combination, to determine the accuracy of sampling and analytical methods. The substances studied in the second phase of the study are summarized in Table I. 

Table I summarizes the sampling media used in the last three years of the study. Previously, we have developed validated sampling and analytical methods for many of the common organic solvents that could be collected on charcoal, desorbed with carbon disulfide, and analyzed by gas chromatography. These procedures are usually nearly identical with the NIOSH method P CAM 127. Likewise, methods for substances that give well-behaved particulates both in collection and analysis had been validated. The substances summarized in Table I represent a wide variety of problems in sampling and analysis. Consequently, many of the samplers were charged with unusual collection media.

In the development of a sampling and analytical method for benzidine-based dyes, the most important feature was the verification of the benzidine moiety in the dye molecule. 

Development of Personal Sampling and Analytical Methods for Organochlorine Compounds... 

In 1971 when safety and health standards were established by the U. S. Department of Labor for several hundred chemical substances, there were analytical methods available for some of the compounds, but few were validated to ensure the accurate monitoring of the exposure of workers to these toxic substances (1). Consequently, programs were undertaken by the National Institute for Occupational Safety and Health (NIOSH) to develop and validate sampling and analytical methods. The initial intent was to provide methods that would be useful to industry in measuring the exposures of personnel to potentially toxic materials at concentration levels near the accepted standard levels. Consequently, many earlier methods were developed around the standard levels established by the Occupational Safety and Health Act with validation at, for example, levels ranging from one-half to twice the established standard level (2). Often these methods were not validated at lower concentration levels, say, one-tenth of the original level. 

Initially, tests were performed to determine the LAQL for each analyte. The long-term stability of each sorbed analyte at its LAQL was also determined. Finally, the accuracy and precision of the analytical method alone and also the overall accuracy and precision of the combined sampling and analytical methods were determined. All tests were performed with the previously developed analytical procedures and sampling devices. 

Development of Air Sampling and Analytical Methods for Toxic Chlorinated Organic Compounds—Research Report for Hexachlorocyclopentadiene", Southern Research Institute, Birmingham, AL, NIOSH Contract No. 210-78-0012, National Institute for Occupational Safety and Health, Cincinnati, OH, 1980. 

Development of Air Sampling and Analytical Methods for Toxic Chlorinated Organic Compounds—Research Report for... 

Conclusions. A sampling and analytical method for two chlorinated isocyanuric acids, NaDCC and TCCA, in air has been described. Briefly, these acids can be collected from air with DM-5000 (PVC copolymer) filters. The filter samples are extracted with water and titrated against sodium thiosulfate using constant-current potentiometry. The titration method will neither separate or distinguish NaDCC in the presence of TCCA or the reverse. The identity of either compound must be known in the workplace environment along with the identities of any other interfering... 

Airborne inorganic acids exist in the industrial environment in the form of both vapors and particulates. This study was undertaken to answer a need for a simple sampling and analytical method for monitoring both vaporous and aerosol acid contaminants quantitatively. 

This overall study of acid mists began with the development of a sampling and analytical method for hydrogen chloride ((>,7). Various solid sorbents and filters, both treated and untreated, were evaluated as collection media and for compatibility with ion chromatography. The sorbent of choice was silica gel which had been washed with deionized water to remove inorganic impurities. 

Sampling and Analytical Precision and Accuracy. The accuracy of results obtained from a sampling and analytical method are determined by comparison with an independent method. The aerosols of phosphoric and sulfuric acids were collected on mixed cellulose ester filters (14 ) and analyzed by ion chromatography. Table V shows the collection efficiency of the 7-mm O.D./700-mg silica gel collection tubes with respect to the results obtained from filter samples, and the precision obtained from calculation of the pooled relative standard deviation. 

The examples presented in this paper are based on results of our laboratory method development and validation studies. These studies, performed at both SRI International and Arthur D. Little, Inc., were supported by the National Institute for Occupational Safety and Health (NIOSH) from 1974 to 1979. In an effort to provide validated sampling and analytical methods for determining worker exposure to toxic substances, we validated existing methods when possible and developed and validated new procedures when no methods were available. Evaluation and testing of solid sorbents played a major role throughout this work ( 1). 

Tests must be performed on a prospective sorbent to ensure validity of the sampling and analytical methods. The criteria established by NIOSH for testing a sorbent are summarized below. Details of these criteria are given in Reference... 

Figure 1 illustrates the procedure that has been used in our laboratories to develop sampling and analytical methods for substances that may be collected on solid sorbents. The general approach will first be discussed, and then an example will be given. In the general approach, several steps may be isolated, but in actual method development, these steps are interrelated. 

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