Lessons learned in preparing method 29 filters for compliance testing audits.

Companies conducting compliance testing are required to analyze audit samples at the time they collect and analyze the stack samples if audit samples are available. Eastern Research Group (ERG) provides technical support to the EPA's Emission Measurements Center's Stationary Source Audit Program (SSAP) for developing, preparing, and distributing performance evaluation samples and audit materials. These audit samples are requested via the regulatory Agency and include spiked audit materials for EPA Method 29-Metals Emissions from Stationary Sources, as well as other methods. To provide appropriate audit materials to federal, state, tribal, and local governments, as well as agencies performing environmental activities and conducting emission compliance tests, ERG has recently performed testing of blank filter materials and preparation of spiked filters for EPA Method 29. For sampling stationary sources using an EPA Method 29 sampling train, the use of filters without organic binders containing less than 1.3 microg/in.2 of each of the metals to be measured is required. Risk Assessment testing imposes even stricter requirements for clean filter background levels. Three vendor sources of quartz fiber filters were evaluated for background contamination to ensure that audit samples would be prepared using filters with the lowest metal background levels. A procedure was developed to test new filters, and a cleaning procedure was evaluated to see if a greater level of cleanliness could be achieved using an acid rinse with new filters. Background levels for filters supplied by different vendors and within lots of filters from the same vendor showed a wide variation, confirmed through contact with several analytical laboratories that frequently perform EPA Method 29 analyses. It has been necessary to repeat more than one compliance test because of suspect metals background contamination levels. An acid cleaning step produced improvement in contamination level, but the difference was not significant for most of the Method 29 target metals. As a result of our studies, we conclude: Filters for Method 29 testing should be purchased in lots as large as possible. Testing firms should pre-screen new boxes and/or new lots of filters used for Method 29 testing. Random analysis of three filters (top, middle, bottom of the box) from a new box of vendor filters before allowing them to be used in field tests is a prudent approach. A box of filters from a given vendor should be screened, and filters from this screened box should be used both for testing and as field blanks in each test scenario to provide the level of quality assurance required for stationary source testing.

Analysis of candidate anticancer drugs by thermospray high-performance liquid chromatography-mass spectrometry.

Thermospray high-performance liquid chromatography-mass spectrometry was used to confirm the identity of five bulk anticancer drugs, and in some cases, to identify drug impurities. Analysis resulted in both molecular weight and structural (fragment ions) information obtained from the full scan spectra of as little as 50 ng of each drug. The technique was also used to evaluate the chromatographic specificity of corresponding ultraviolet or refractive index high-performance liquid chromatographic detection in the presence of drug degradation products.

A comparison of thermospray and direct liquid introduction high-performance liquid chromatography/mass spectrometry for the analysis of candidate antimalarials.

The analysis of antimalarials by high-performance liquid chromatography (HPLC)/mass spectrometry demonstrates a new dimension in specificity along with increased sensitivity compared to conventional HPLC detection methods. Both direct liquid introduction and thermospray HPLC/mass spectrometry interfaces provided molecular weight information as well as characteristic fragment ions for antimalarials not normally amenable to direct probe or gas chromatographic/mass spectrometric techniques. The direct liquid introduction interface, which incorporated a 1/100 split, showed a detection limit of 30 ng using selected ion monitoring. The thermospray technique showed less than 1 ng detection limits using selected ion monitoring.

Evaluation of immunoassays for cannabinoids in urine.

A comparison was made of several cannabinoid urine assays. Two hundred randomly selected urine specimens were initially screened by two enzyme immunoassays (EMIT-st and EMIT-d.a.u.) and a radioimmunoassay (Abuscreen RIA). Selected specimens found positive by any of these methods were further analyzed by gas-liquid chromatography with flame ionization detection (GLC/FID), gas chromatography/mass spectrometry (GC/MS), and an experimental RIA from Research Triangle Institute (RTI RIA). The GLC/FID method gave confirmations in 69 to 92% of the samples, depending on the method used and the cut-off employed. GC/MS confirmed 98% of the EMIT and RIA positives using a low cut-off (20 ng/mL). All RIA positives at 100 ng/mL were confirmed by GC/MS. There was complete agreement between the RTI RIA and the EMIT assays, but not with the Abuscreen RIA at the 100 ng/mL cut-off. The study illustrates that care must be exercised in establishing assay cut-offs and the designation of false positive results.

Gas chromatography mass spectrometry computer analysis of volatile halogenated hydrocarbons in man and his environment--A multimedia environmental study.

As part of a study to make a comparative analysis of selected halogenated compounds in man and the environmental media, a quantitative gas chromatography mass spectrometric analysis of the levels of the halogenated compounds found in the breath, blood and urine of an exposed population (Old Love Canal area, Niagara, New York) and their immediate environment (air and water) was undertaken. In addition, levels of halogenated hydrocarbons in air samples taken in the general Buffalo, Niagara Falls area were determined.

Method for analysis of polybrominated biphenyls by gas chromatography mass spectrometry.

Gas chromatography using a short packed column (45 cm, 0.2 cm i.d., 2% OV-101 on Gas-Chrom Q) with mass spectrometric detection in the selected ion monitoring mode has been found satisfactory for the analysis of lower as well as higher polybrominated biphenyls. Acceptable sensitivity (< 1 ng) may be achieved for this method by focusing selectively at either the low (m/z 20-600) or the high m/z 600-1000) range of the quadrupole filter (low range for mono- through hexabromobiphenyl, high range for hexa- through decabromobiphenyl). A tuning technique has been developed for low range and high range polybrominated biphenyls using the ion abundances of perfluorotributylamine as a standard. Standard ions for the quantitation of mono- through decabromo-biphenyls were selected and validated. The technique was applied to the analysis of a variety of environmental samples.

Comparison of gas chromatography mass spectrometry methods for the determination of delta9-tetrahydrocannabinol in plasma.

A method for the identification of delta9-tetrahydrocannabinol by gas chromatography mass spectrometry has been developed, and this method has been compared with other techniques, such as detection via thin-layer chromatography using tritium labeled delta9-tetrahydrocannibinol and a dual gas chromatographic method. The gas chromatographic mass spectrometric method was found to be equal or superior to other techniques and has the added advantage of being highly specific for the compound analyzed. An alternate approach using chemical ionization is also described; however, this procedure does not show significant advantages over the electron impact method. These methods show a practical lower detection limit of 500 pg ml-1 of plasma in clinical practice.

Identification of N-nitrosodimethylamine in ambient air by capillary gas-liquid chromatography mass spectrometry computer.

Organic vapors in ambient air, at or near an industrial site in Baltimore, Maryland, were collected by adsorption on a sorbent of porous polymer (Tenax GC, 35/60). The pollutants were recovered by thermal desorption and analyzed by gas-liquid chromatography mass spectrometry computer using capillary glass SCOT columns. N-Nitrosodimethylamine was identified from its mass spectrum as a constituent of the atmosphere in the areas sampled. The identification of this compound was confirmed by comparison of its mass spectrum with that of authentic N-nitrosodimethylamine; identical retention times of unknown and authentic compound on three different capillary columns were observed.

Analytical methods for the determination of cannabinoids in biological media.

A pharmacokinetic study of the blood plasma levels in man of delta9-tetrahydrocannabinol, 11-hydroxy-delta9-tetrahydrocannabinol and cannabinol has been carried out by means of combined gas chromatographic-mass spectral analysis. In some cases comparison of the data was obtained on the same sample using thin layer chromatography of radiolabeled samples and electron capture gas-liquid chromatography. For the mass spectral studies appropriately deuterium labeled analogs of the previously named compounds were used both as internal standards and as a carrier for the relatively small amounts of nonlabeled drug present in plasma. Blood samples were obtainted at periodic intervals up to 24 hours from volunteers receiving 4-5 mg delta9-THC intravenously. After extraction and "clean-up" by Sephadex chromatography, the extracts were concentrated and subjected to glc-ms in the electron impact (ei) mode or alternatively with a chemical ionization (ci) source, in which case preliminary chromatography could be omitted. In all cases calibration curves were obtained from replicate analyses of spiked plasma containing the internal standard and various quantities of the cannabinoid under analysis. A typical biphasic elimination of the drug was observed with rapid elimination of delta9-THC from the blood over a period of 40 min followed by a much slower elimination up to 24 hours. The experimental data show that 11-hydroxy-delta9-THC is found in the plasma in quantities only about one-twentieth to one-twenty-fifth the values found for delta9-THC. Cannabinol was not found in significant quantities. Good agreement was obtained between the mass spectral analyses and the thin layer chromatography or electron capture gas-liquid chromatographic procedures.