Comparison of pressurized fluid extraction, Soxhlet extraction and sonication for the determination of polycyclic aromatic hydrocarbons in urban air and diesel exhaust particulate matter.

In order to characterize and compare the chemical composition of diesel particulate matter and ambient air samples collected on filters, different extraction procedures were tested and their extraction efficiencies and recoveries determined. This study is an evaluation of extraction methods using the standard 16 EPA PAHs with HPLC fluorescence analysis. Including LC analysis also GC and MS methods for the determination of PAHs can be used. Soxhlet extraction was compared with ultrasonic agitation and pressurized fluid extraction (PFE) using three solvents to extract PAHs from diesel exhaust and urban air particulates. The selected PAH compounds of soluble organic fractions were analyzed by HPLC with a multiple wavelength shift fluorescence detector. The EPA standard mixture of 16 PAH compounds was used as a standard to identify and quantify diesel exhaust-derived PAHs. The most effective extraction method of those tested was pressurized fluid extraction using dichloromethane as a solvent.

Scaled down method for the reproducible recovery to high purity of human serum albumin from low volume blood samples.

A basic need for a protein-based dosimeter is a purified protein. In this communication we present an isolation protocol and an HPLC-based assay which allows one to determine the purity of the isolated albumin. A total of 168 human blood samples were collected from workers of a benzene processing plant and from nearby countryside at Kohtla-Järve, Estonia. Albumin was isolated from plasma by sequential precipitation and the purity was determined by HPLC. The amount of albumin present in plasma varied between the individuals, being 147 +/- 26 mg/5 ml (n = 168), which is about 59% of plasma albumin. However, the isolated albumin was highly pure (100.9 +/- 8.2%, n = 5). All albumin samples analyzed demonstrate two peaks in HPLC analysis. The two peaks detected were collected and subjected to MS analysis, which demonstrates a difference of 120 mass units between the two albumin products isolated. We have developed an assay, which is easy to carry out and is not too labor intense. The HPLC analysis can be applied to confirm the purity of the isolated albumin as well as to confirm the quantity of the albumin in samples.