C. Chiu

Analysis of polycyclic aromatic hydrocarbons in sediment reference materials by microwave-assisted extraction

The microwave-assisted extraction (MAE) of polycyclic aromatic hydrocarbons (PAHs) from harbor sediment reference material EC-1, marine sediment reference material HS-2 and PAH-spiked river bed soil was conducted. The extraction conditions for EC-1 were carried out at 70 degrees C and 100 degrees C under pressure in closed vessels with cyclohexane acetone (1:1), cyclohexane-water (3:1), hexane acetone (1:1), and hexane-water (3:1) for 10 min. A comparison between MAE and a 16-h Soxhlet extraction (SX) method showed that both techniques gave comparable results with certified values. MAE has advantages over the currently used Soxhlet technique due to a faster extraction time and lower quantity of solvent used. The consumption of organic solvent of the microwave method was less than one-tenth compared to Soxhlet.

Polychlorinated hydrocarbons from fower plants, wood burning and municipal inc inerators

Abstract Representative stack and flyash samples were obtained from various combustion sources. Analyses indicated that the polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are consistently found in incinerators and that power plants contained only a trace of these compounds. A study of some I someric PCDD and PCDF compounds has been conducted using capillary GC/NEGATIVE CI/MS using townsend discharge ionization with O 2 . The fragmentation patters for individual I somers show differences indicative of the positional distribution of chlorine in the molecule. The specific ionization process, coupled with the high resolution GC collumns, provides a selective, highly sensitive detection ststem for the analysis of PCDD and PCDF.

Internal quality assurance requirements for the analysis of dioxins in environmental samples

Abstract A document has been prepared which specifies those elements of a laboratory quality assurance (QA) program which are considered essential in order to ensure the reliability of dioxin data generated in support of Canadian government programs. The document also establishes performance criteria by which data quality may be assessed. By focusing on principles and performance rather than procedural details, laboratories are afforded the flexibility to follow specific procedures of their own choosing, and the governments need to develop reference methods for individual environmental matrices is simplified or eliminated.

CORRECTION OF ANALYTICAL RESULTS FOR RECOVERY: DETERMINATION OF PAH s IN AMBIENT AIR, SOIL, AND DIESEL EMISSION CONTROL SAMPLES BY ISOTOPE DILUTION GAS CHROMATOGRAPHY-MASS SPECTROMETRY

Results from soil, diesel emission and ambient air control particulate matter samples on the determination of 30 PAHs were evaluated to establish whether the use of recovery data would result in an improvement of the quantitation accuracy over the uncorrected data. The performance of the recovery-corrected technique was initially evaluated using recovery results from PAH standard reference material samples spiked with analogue deuterated isotopes. The results showed an excellent correlation between recoveries of natives and corresponding surrogates for all matrices studied. The practical merit of the isotope dilution mass spectrometry technique was further assessed by spiking control samples with corresponding isotopic analogues and comparing the measured concentration of natives obtained with uncorrected and recovery-corrected techniques. The data revealed that the use of recovery correction leads to results closer to the real values, thus decreasing the negative bias due to losses that occur during the analytical process. The mean accuracy difference between uncorrected and corrected data is more pronounced as the sample matrix becomes more complex, such as soil (15 ± 12%) or diesel emission (8 ± 11%), and less for simpler ambient air matrix samples (3 ± 16%). Precision between the two techniques was comparable within each matrix and relatively close between the different matrices.

Refined analytical procedures to detect and measure PCDD/PCDF, PAH, PCB, CB, and CP in environmental samples

Abstract Attempt has been made for the development of a protocol to detect and to determine the specific compound groups in various media matrices. The developed Procedure has been further refined here to reflect the improvements which are made to reproducibility, recoveties and QA/QC programs etc. Its merit and application to the analysis of incinerator fly ash samples is illustrated.

Interference of Transformer oil Matrices to the Internal Standards on PCB Quantification

Abstract Polychlorinated biphenyls (PCBs) are toxic, perssstent, global environmental contaminants which were formulated as complex mixtures of congeners. Many methods have been developed in the past to analyze PCB in transformer oil samples for regulatory purposes. The most important consideration in the cleanup procedure is the ability to remove the oil from the sample matrix, since trace amount of oil will interfere with the subsequent GC-MS analysis. Electron capture detection (ECD) has been the most common method for gas chromatographic analysis of PCBs because of its high sensitivity toward halogenated compounds. ECD can also respond to some non-PCB compound resulting in biased concentrations of PCB. In this work, a two-stage cleanup method, using DMSO liquid/liquid extraction and HPLC column chromatography. has been applied to two types of transformer oil. Five internal standards have been selected to show their performance in the presence of different oil matrices. The comparison of the PCB quanti...

Automated PCB Analysis, Quantitation and Reporting

Abstract Sample analysis from a variety of matrices was performed using Gas Chromatography-Mass Spectrometry (GC-MS). Average relative response factors were calculated for each polychlorinated biphenyl homologue (tri-to deca-chlorobiphenyl) using in-house calibration standard solutions. Sample quantitation using RRFs provided homologue specific results. A series of software macros were used to automate the interpretation of spectral data and the selection of possible PCB congener peaks.

Interlaboratory comparison study of polychlorinated dibenzo-p-dioxins and dibenzofurans analyzed under the National Incinerator Testing and Evaluation Program

Abstract One portion of Environment Canadas National Incinerator Testing and Evaluation Program (NITEP) involved an interlaboratory Comparison study of various incinerator-related matrices for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF). Three replicates of two different types of incinerator process samples were analyzed by three laboratories. Statistical analysis of recovery corrected PCDD/PCDF data indicated that the three laboratories exhibited reasonably good repeatability (or precision). However, significant differences existed in the between-laboratory results.

Interlaboratory comparison studies on the measurement of PCDD/PCDF in pulp and paper matrices

Abstract Results of two interlab comparison studies for the analysis of PCDD and PCDF in pulp, sludge and effluent samples are described and compared. The agreement of results among labs were improved significantly by providing common calibration standards and specifying key elements of analytical procedures as mandatory requirements

The effect of temperature on GPC for the separation of PCBs from transformer oil and subsequent analysis by GC-MSD

The analysis of PCBs often involves lengthy and expensive cleanup procedures to remove interferences associated with environmental sample matrices. Gel permeation chromatography (GPC) has proven to be a useful tool in removing many of these interferences from environmental samples, especially from difficult matrices such as oils, lipids and sediments. This paper describes the effect of temperature upon the GPC column in separating PCBs from transformer oil and its implication on GC-MS analysis.