Studies of uptake, elimination, and late effects in Atlantic salmon (Salmo salar) dietary exposed to Di-2-ethylhexyl phthalate (DEHP) during early life.

The phthalate esters are a group of industrial chemicals considered to have endocrine-disrupting properties. The most common tonnage product among these, di-2-ethylhexyl phthalate (DEHP), is widely spread in the environment. The objectives with the present work were to study uptake and metabolism of orally administered DEHP and its major metabolite mono-2-ethyl hexyl phthalate (MEHP) and to evaluate the impact of early life exposure on sex differentiation in Atlantic salmon. The feeding with contaminated diet started immediately after yolk sac resorption and continued for 4 weeks. Nominal concentrations of DEHP in the diet were 400 (measured 359), 800 (measured 827), and 1500 (measured 1648) mg DEHP/kg and a control group was fed food mixed with solvent. After the exposure period, fish were fed non-contaminated diet until final sampling 4 months post-exposure. There were no effects on growth or survival of the fish and no late effects on hepatosomatic index or sex ratio. However, the histological examination of gonads from fish exposed to 1500 mg DEHP/kg revealed a small but significant incidence (3%) of intersex fish (ovo-testis). Chemical residues of DEHP and MEHP were analyzed weekly during the first 3 months of the post-exposure period. Both DEHP and MEHP were rapidly eliminated to near background levels within one week post exposure. The study indicates that exposure of Atlantic salmon to relatively high concentrations of DEHP during a sensitive part of the life cycle may interfere with gonad differentiation.

Computerized separation of chromatographically unresolved peaks.

A computerized peak deconvolution software and mass spectra were successfully applied for the deconvolution of overlapped peak cluster in the chromatogram obtained separating the complex mixture of pesticides by retention time locking gas chromatography-mass spectroscopy. The method based on the unique fragment ions in the spectra can be used for deconvolution of peak clusters if mass spectra of overlapped peaks differ. This method allows determining actual retention times of overlapped peaks. Peak areas found by this method however, cannot be used naturally for the quantitative purposes as the abundance of fragment ions used for this deconvolution procedure can dramatically differ. Computer assisted deconvolution of peaks in the peak clusters gives more realistic peak area ratios as at this method it is supposed equal response for all peaks overlapped in a cluster.

Stir bar sorptive extraction-thermal desorption-capillary GC-MS for profiling and target component analysis of pharmaceutical drugs in urine.

Stir bar sorptive extraction (SBSE) in combination with thermal desorption (TD) on-line coupled to capillary gas chromatography-mass spectrometry (CGC-MS) was applied to the analysis of pharmaceutical drug compounds and metabolites in urine. SBSE implies stirring of the aqueous sample (urine, blood, etc.) with a glass stir bar coated with a thick layer (24 microl) of polydimethylsiloxane (PDMS) for sorptive enrichment of the analytes of interest. In combination with quantitative TD, on-line coupled with CGC-MS, the technique showed to be very versatile and sensitive for the analysis of a wide range of drug substances. Moreover, the relative high enrichment efficiencies of SBSE allow to use mass spectrometric detection (MSD) in the full scan mode. In situ derivatization of polar compounds before SBSE is demonstrated for the analysis of paracetamol and this resulted in both improved chromatographic behavior and higher sensitivity. The quantitative performance of SBSE-TD-CGC-MS is illustrated with the analysis of some barbiturates in urine.

Stir bar sorptive extraction-thermal desorption-capillary GC-MS applied to biological fluids.

A new sample preparation method, stir bar sorptive extraction (SBSE), has been evaluated for the enrichment of organic solutes from biological fluids such as urine and blood. In SBSE, a stir bar coated with a polydimethylsiloxane layer is stirred for a given time in the sample. After sampling the stir bar is placed in a thermal desorption unit coupled on-line to capillary gas chromatography-mass spectrometry (SBSE-TD-CGC-MS). The principle and operation of SBSE are presented. Total profiling and target compound analysis have been selected as applications to illustrate the performance of SBSE-TD-CGC-MS (MSD). It is demonstrated that a variety analytes ranging from biological markers (phenols, hormones, fatty acids) to artificial contaminants (recreational drugs, plasticizers) can be enriched with high sensitivity. For polar solutes, in-situ derivatization can enhance both recovery into the polydimethylsiloxane (PDMS) layer and chromatographic analysis. Two types of derivatization have been applied, derivatization with ethyl chloroformate and with acetic acid anhydride. Linearity, detectability, and repeatability are illustrated by the determination of 1-hydroxypyrene in a urine sample from a smoker.

Stir bar sorptive extraction applied to the determination of dicarboximide fungicides in wine.

The dicarboximide fungicides vinclozolin, iprodione and procymidone were analyzed in white wines using stir bar sorptive extraction (SBSE) in combination with thermal desorption-capillary GC-MS analysis (TD-cGC-MS). The method was optimized using spiked water samples in a concentration range between 0.5 and 100 microg/l. Iprodione was measured as its degradation product 3,5-dichlorophenyl hydantoin. Limits of quantification in the full scan MS mode are 0.5 microg/l for vinclozolin and procymidone and 5 microg/l for iprodione. In the ion monitoring mode, concentrations 100 times lower can be dosed. Because of wine matrix effects on the recoveries, quantification of the target fungicides in wine had to be carried out by standard addition. For the thermolabile iprodione, the accuracy of SBSE-TD-cGC-MS was verified using SBSE followed by liquid desorption and analysis by liquid chromatography-atmospheric pressure chemical ionization mass spectroscopy. Procymidone and iprodione were detected in wines in concentrations up to 65 microg/l while the highest concentration of vinclozolin detected was smaller than 3 microg/l.

Pyrolysis-capillary gas chromatography-mass spectrometry for the determination of polyvinyl chloride traces in solid environmental samples.

A novel method based on pyrolysis-capillary gas chromatography-mass spectrometry (CGC-MS) was developed for the quantitative analysis of polyvinylchloride (PVC) in solid environmental samples like sludge and dust. The samples are extracted and the extract is fractionated by solid-phase extraction (SPE). Possibly interfering biological and frequently occuring synthetic polymers are removed by this clean-up. The final extract is analyzed by pyrolysis-CGC-MS. Selective detection of PVC is performed by using specific markers in the pyrogram. Quantitation is done on naphthalene. Good linearity was obtained in a range from 0.5 to 100 microg applied to the pyrolyser. The limit of quantitation (LOQ) in sludge and dust samples is 10 mg/kg dry mass. A correlation between PVC and phthalates was made for sewage sludge samples.