Inter-laboratory exercise on steroid estrogens in aqueous samples.

An inter-laboratory comparison exercise was organized among European laboratories, under the aegis of EU COST Action 636: "Xenobiotics in Urban Water Cycle". The objective was to evaluate the performance of testing laboratories determining "Endocrine Disrupting Compounds" (EDC) in various aqueous matrices. As the main task three steroid estrogens: 17alpha-ethinylestradiol, 17beta-estradiol and estrone were determined in four spiked aqueous matrices: tap water, river water and wastewater treatment plant influent and effluent using GC-MS and LC-MS/MS. Results were compared and discussed according to the analytical techniques applied, the accuracy and reproducibility of the analytical methods and the nature of the sample matrices. Overall, the results obtained in this inter-laboratory exercise reveal a high level of competence among the participating laboratories for the detection of steroid estrogens in water samples indicating that GC-MS as well as LC-MS/MS can equally be employed for the analysis of natural and synthetic hormones.

Derivative spectrophotometry in the determination of phenyl-beta-naphthylamine used as an antioxidant in rubber mixtures.

A method for the determination of phenyl-beta-naphthylamine (PBN) in ternary mixtures by second-derivative spectrophotometry is described. The procedure works without any separation step of PBN from the other polymer additives. By applying the second-derivative spectrophotometry, Beer's law was valid over the range 0.25-10 micro g mL(-1). The proposed method has been applied to the determination PBN in synthetic ternary mixtures and rubber samples. A comparative study of the results obtained using the second and the third-derivative spectrophotometric methods is presented and evaluated. The derivative spectrophotometric method indicated that the amount of PBN found after extraction from the rubber samples was 0.97+/-0.02 g/100 g of sample.

Electron impact mass spectral interpretation for some thiophosphoryl-p-acetylaminobenzenesulfonamides.

This work discusses the synthesis and the fragmentation patterns for 2-(p-acetylaminosulfonamido)-2-thiono-(5,5-dimethyl-1,3,2-dioxaphosphorinane)(1) and for the p-acetylaminosulfonylamides of O,O-diethylthiophosphoric acid (2), O,O-diphenylthiophosphoric acid (3), dimethylaminocyclohexylthiophosphoric acid (4), and diethylaminophenylthiophosphoric acid (5). A thionamidic-thiolimidic structure was attributed to compounds 1-5, consistent with their IR and NMR spectra. EI mass spectra at 70 eV, high resolution (HR) mass measurements and metastable ion spectra were used to elucidate the fragmentation processes and to determine the kinetic energy release values associated with the metastable ion dissociations. HR accurate mass measurements were used to confirm the compositions of the more abundant ions.

Determination of novel aromatic amines in environmental samples by gas chromatography/mass spectrometry.

A number of compounds belonging to five chemical classes of aromatic amines were identified by electron impact mass spectrometry, both in the vapor phase and in suspended particulate matter collected in an area subjected to heavy traffic. This paper presents the mass spectra of new aromatic amines, proposed mechanisms for formation of the major ions obtained by electron impact, concentrations of each class in 13 environmental samples, and the distribution of the individual compounds of the major chemical classes (greater than 80% by weight).

Isotope dilution mass spectrometry for procaine determination in biological samples.

A simple, rapid and sensitive method for procaine determination is described. Isotope dilution mass spectrometry with (15N)procaine as internal standard was used. The analysis was performed at 4000 resolution by selected ion monitoring with temperature programming. The sample was measured in underivatized form in the direct inlet system. The method shows good analytical parameters: linearity between 0 and 40 micrograms ml-1, good precision and accuracy. The method was applied to the in vitro pharmacokinetic study of the metabolism of procaine in liver homogenates of Wistar rats. The method is rapid, permitting about six samples to be run per hour. Sensitivity of the method permits analysis at a signal-to-noise ratio of 5:1.

Serum theophylline analysis by isotope dilution mass spectrometry.

Serum theophylline analysis was attempted using stable isotope dilution mass spectrometry. Theophylline 15N-labelled in position 7 was used as internal standard. The analysis was performed at resolution 3000 by selected ion monitoring with temperature programming. The sample was introduced in underivatized form by means of the direct inlet probe. Good linearity was obtained in the concentration range 5-40 micrograms ml-1 with relative standard deviations less than 6%. The method is simple and permits six samples to be run per hour. Sensitivity permits analysis at 0.5 micrograms ml-1 at a signal to noise ratio 4:1.