Determination of phenols and chlorophenols as trimethylsilyl derivatives using gas chromatography-mass spectrometry.

A rapid and simple method is described for the simultaneous determination of 6 phenols (phenol, o-, m-, p-cresol, catechol and resorcinol) and 19 chlorophenols (all mono-, di-, tri-, and tetrachlorophenol isomers and pentachlorophenol) present in aqueous samples. The method is based on derivatization with trimethylsilyl-N,N-dimethylcarbamate (TMSDMC). In contrast to other derivatization agents, TMSDMC instantaneously reacts with the phenolic compounds at room temperature and no further sample processing is necessary prior to instrumental analysis. The determination of the derivatives was performed by capillary gas chromatography-mass spectrometry (GC-MS). The stability of the most instable trimethylsilyl derivative (pentachlorophenol) was studied using different excess levels of the derivatization reagent. The derivatization method was tested on spiked water samples preconcentrated by solid phase extraction on Isolute ENV+ cartridge. The overall method gave detection limits of 0.01-0.25 microg/L for all compounds and < 0.05 microg/L for 17 of them.

Detection of tinuvin 770, a light stabilizer of plastic materials from dialysis membranes, by high-performance liquid chromatographic analysis.

Tinuvin 770 [bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate] is a pharmacologically active agent used worldwide as a light stabilizer for plastic materials. In vitro studies show that it is an L-type Ca(2+) channel and neuronal nicotic acethylcholine receptor blocker. Hypotension, vegetative dysfunction, and neurological symptoms are frequently observed during a haemodialysis treatment. The release of Tinuvin 770 from plastic materials applied in haemodialysis may play a part in the development of clinical signs. In our study, four different commonly used haemodialysis membranes (polysulphon, cuprophan, and two types of hemophan) are examined. The polymers are soaked for 72 h in physiological saline solution. Isolation is carried out using a Waters Oasis SPE column for solid-phase extraction and by high-performance liquid chromatography (HPLC) with electrospray ionization-mass spectrometric detection. Tinuvin 770 release is detected from all examined membranes. Validation studies show a satisfactory selectivity, linearity, accuracy, and recovery of this method. Our results suggest that Tinuvin 770 could have specific toxicological and therapeutic importance related to haemodialysis treatment. The developed HPLC method is suitable for the detection of Tinuvin 770.