Microsampling Method Research Articles

Unmanned noise source identification via analog tape microsampling

A new method of analog tape microsampling is discussed. The method centers about a controller which turns the analog tape recorder on and off at a low sample rate at low sound levels and at a high sample rate at sound levels above a preset threshold. Results of its application to airport/aircraft/community noise environments are discussed with regard to accuracies of level statistics and source identification.

A micro-sampling method for the determination of blood lead

The analytical micromethod discussed here has been found to be very rapid, accurate, and relatively inexpensive for the determination of blood and urine leads. It has the distinct advantage in that a determination can be repeated. The sensitivity of the method is 1.37 × 10 −10 g per 1% absorption at 283.3 nm. Our laboratories have analyzed 7353 specimens in duplicate or more from March 17, 1971 to April 30, 1972. Considering the many possible sources of contamination (the mobile unit being more so than a clinic) it is the Division of Chemistry's conclusion that an agreement of 84% is good and that a finger-stick method is feasible, and therefore, a complete micro-screening for blood lead is possible.

A Kinetic Study of 131I-BSP in Rat with Sequential Micro-Sampling Method

A Kinetic Study of ¹³¹I-BSP in Rat with Sequential Micro-Sampling Method

Analysis of base composition of RNA and DNA hydrolysates by gas-liquid chromatography

A quantitative gas-liquid chromatographic method has been developed for the analysis of the base composition of ribonucleic acid and deoxyribonucleic acid hydrolysates at the macro (1.0 mg) and semimicro (100 μg) levels of total nucleic acids, and a semi-quantitative method for micro samples (500 ng of each base). An anion-exchange cleanup procedure to remove perchlorates, phosphates, and other interfering products released during hydrolysis of the sample is included. Silylation of the bases was conducted in a closed reaction vial with bis(trimethylsilyl)-trifluoroacetamide; with chromatography on a 10 w/w% SE-30 100/120 mesh Supelcoport column. Three different ribonucleic acids and two deoxyribonucleic acids were analyzed at the three levels. The results at each level were precise and in good agreement with literature values.

Determination of lead in capillary blood using a paper punched disc atomic absorption technique. Application to the supervision of lead workers.

<b>Cernik, A. A., and Sayers, M. H. P. (1971).</b><i>Brit. J. industr. Med.,</i><b>28,</b> 392-398. <b>Determination of lead in capillary blood using a paper punched disc atomic absorption technique. Application to the supervision of lead workers.</b> The presence of lead in blood is the most incontrovertible evidence of absorption but hitherto the need for venepuncture has limited its determination in the supervision of industrial workers. Micro-methods using atomic absorption spectrophotometry (AAS) have, however, made possible the development of a sufficiently reliable test using a drop of blood obtainable by ear prick for use in the field for screening purposes. A micro-sampling method by AAS is compared with a routine polarographic procedure (POL) using venous blood (corr. coeff. = 0·990). The pipetting of microlitres of blood can be eliminated by spotting the blood onto filter paper, allowing it to dry in air, and then using a punched-out standard disc of dried blood for analysis instead. Correlation of this method (PD) with the micro-sampling technique (AAS) is good (r=0·981). The PD method using capillary blood also correlates acceptably with the micromethod using venous blood (r = 0·913). A pilot field study using capillary blood estimated by the PD technique showed that with this method blood can be collected by ear prick in factories for monitoring workers in the lead industry, thus eliminating the need for routine venepuncture.

A micro-sampling method for the rapid determination of lead in blood by atomic-absorption spectrophotometry.

The concentrations of lead in 10-µl samples of whole blood are accurately determined in less than 5 minutes by atomic-absorption spectrophotometry. After partial oxidation with hydrogen peroxide in micro crucibles made from nickel foil, the samples are volatilised, by using an air-acetylene flame, into a nickel absorption tube situated in the flame.The sensitivity of the method is 1 × 10–10 g of lead per 1 per cent. absorption at 283·3 nm, and the standard deviation is ±4 per cent. at the 3-ng level.Thirty-nine blood samples with lead concentrations ranging from 19 to 245 µg per 100 ml were analysed by the method described and by automated colorimetry involving the use of dithizone. The correlation coefficient between the results of both methods was 0·989.

Determination of thallium in biological material by flame spectrophotometry and atomic absorption.

Flame-spectrophotometric and atomic-absorption methods of assaying trace amounts of thallium in biological material have been investigated. With the Perkin-Elmer, Model 303, spectrophotometer atomic absorption is the more sensitive and yields detection limits comparable with those reported in the literature for the most sensitive types of flame-emission equipment. A simple and rapid method of micro sampling by using a tantalum boat is described. It enables nanogram amounts of thallium (down to 3 ng) in 50 to 100 µl of blood and urine to be determined with an accuracy and precision of 3 to 5 per cent. This represents an increase in sensitivity of at least twenty-five times over conventional atomic-absorption spectrophotometry. The results obtained with the tantalum boat are susceptible to inter-element interferences, and calibration by using the additions method is essential for accurate quantitative results.