Capillary Gas Chromatography-negative Chemical Ionization Research Articles

Determination of organophosphorus pesticide residues in human tissues by capillary gas chromatography–negative chemical ionization mass spectrometry analysis

We describe an analytical method that allows the determination of organophosphorus pesticides (OPs) in different human tissues. It involves an extraction procedure with ethanol–ethyl acetate, followed by gel permeation chromatography clean-up step and analysis by capillary gas chromatography–negative chemical ionization mass spectrometry in the selected ion monitoring mode. The method was tested for 37 OPs and the recoveries obtained vary between 60 and 106% with standard deviations ranging between ±2 and ±10. These values are independent of the analyzed tissue. Peak area repeatability as RSD for some OPs was ≤4.8% while a good linear relationship in the range 1.0–500 pg μl −1 with r 2≥0.9878 was obtained. The limit of detection for the 37 OPs falls between 0.01 and 0.09 ng g −1 with an RSD≤9.5%. The analytical set up in this paper has been used to analyze different samples of human tissues (liver, healthy kidney, cancer kidney and adipose tissue) of 24 patients. The number of the identified OPs in the tissue samples is different (max. 20) according to the sample while their concentration ranges between the limit of detection and 28.0 ng g −1. The highest concentrations have been determined in liver samples without any pathology (0.4–28.0 ng g −1) while the lowest concentrations have been determined in healthy kidney samples (0.01–1.50 ng g −1). In the cancer kidney samples OP concentrations vary between 0.03 and 4.6 ng g −1: these concentrations are more elevated than those determined in healthy kidney samples. The comparison between the concentration of OPs determined in the healthy part, when possible, and those determined in the cancer part of the same kidney sample are very interesting: in fact, in the latter the OP concentration is generally 1–2-times higher than that in the former, an index of lower enzymatic activity in the cancer tissue.

Characterization of a novel diclofenac metabolite in human urine by capillary gas chromatography-negative chemical ionization mass spectrometry.

A sensitive analytical method was developed to characterize diclofenac metabolites in small amounts of body fluids. Desalted and lyophilized urine samples were extracted with supercritical carbon dioxide directly or after acidic hydrolysis. The extracts were derivatized with N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamide. The derivatives were separated by capillary gas chromatography and identified by negative chemical ionization mass spectrometry. Full mass spectra were obtained at a level of 1.10(-9) g/ml. With direct extraction, the metabolites could be analysed in one step as open-chained acids and as (cyclic) oxindoles. By acidic hydrolysis the conjugates were transformed to the oxindoles. With both methods, a new main metabolite, [2-[2,6-dichloro-4-hydroxy-3-methoxyphenyl)amino]phenyl]acetic acid, was identified The mechanism of its formation is discussed.

Organochlorine pesticides and polychlorinated biphenyls in the atmosphere of Southern Sweden

High volume air samples were taken in Stockholm and at a rural site approximately 100 km south of the city using a glass fiber filter-polyurethane foam (PUF) collector. The samples were analyzed for polychlorinated biphenyls (PCB), DDT compounds, hexachlorocyclohexanes (HCH), hexachlorobenzene (HCB), chlordanes and polychlorocamphenes (PCC) by capillary gas chromatography with electron capture detection (GC-ECD), and for chlordanes and PCC by capillary gas chromatography-negative chemical ionization mass spectrometry (GC-MS). Geometric mean concentrations (pg m −3) were: PCB (Aroclors 1242 + 1254) = 165, p,p'-DDT + p,p'-DDE = 7.2, HCH = 489, HCB = 64, chlordane = 8.4 and PCC = 25. Examination of air trajectories suggested that some of the PCC in the air over Sweden may be derived from sources in eastern Europe.

Detection of phenolalkylamines by capillary column gas chromatography-negative chemical ionization mass spectrometry

Twelve phenolalkylamines normally used in different pharmaceutical products were determined in urine from volunteers given a therapeutical dose of the drug. The urine extracts were first derivatized with perfluoro propionic or butyric anhydride, then detected by capillary gas chromatography—negative chemical ionization mass spectrometry. The method is highly sensitive and specific in the analysis of biological samples.

A new technique for the determination of diethylstilboestrol.

A new method has been developed to determine diethylstilboestrol (DES) in bovine urine at the picogramme level. Ion-pair-systems are used for purification and isolation. Following formation of the electrophilic di-heptafluorobutyryl (di-HFB) derivative, identification and quantification were carried out by means of capillary gaschromatography-negative chemical ionization mass spectrometry, using CH4 or CH4-N2O 4: 1 as reagent gases.