Multiresidue determination of quinolone antibacterials in eggs of laying hens by liquid chromatography with fluorescence detection.

An analytical method for the simultaneous determination of seven quinolones (ciprofloxacin, enrofloxacin, danofloxacin, difloxacin, flumequine, oxolinic acid and sarafloxacin) in egg samples of laying hens was developed. Their use is totally prohibited in animals from which eggs are produced for human consumption. Protein precipitation was achieved by addition of acetonitrile and ammonia, removal of acetonitrile with dichloromethane, the quinolones remaining in the basic aqueous extract. The aqueous extract was analysed by liquid chromatography with fluorescence detection (LC-FD). The mobile phase was composed of acetonitrile and 10 mM citrate buffer solution of pH 4.5, with an initial composition of acetonitrile-water (12:88, v/v) and using linear gradient elution. Norfloxacin was used as an internal standard. The limits of detection found were 4-12 ng g(-1). These values were lower than the maximum residue limits (MRLs) established by the European Union for these compounds in different tissues of eggs-producing animals.

Bisphenol-A and chlorinated derivatives in adipose tissue of women.

Bisphenol-A (BPA) and chlorinated derivatives (Cl(x)BPA) were investigated in adipose tissue of women in Southeast Spain. BPA was above limit of detection (LOD) in 11 out of 20 samples (55%). Among Cl(x)BPA, Cl(2)BPA was the most frequent (80%) and abundant, constituting 94.6% of total chlorinated BPA in adipose tissue. Mean +/- S.D. of BPA, monochloro-BPA (ClBPA), dichloro-BPA (Cl(2)BPA), and trichloro-BPA (Cl(3)BPA) were 5.83 +/- 3.48, 3.05 +/- 0.28, 9.21 +/- 9.26, and 0.74 +/- 0.15 ng/g of adipose tissue, respectively. No tetrachloro-BPA (Cl(4)BPA) was found above LOD. There are no published data on BPA in human adipose tissue or on Cl(x)BPA in adipose tissue or blood, limiting comparisons. BPA levels were similar (w/w) to findings in blood (w/v) in other populations and below levels reported in placenta tissue (w/w). Because of the estrogen mimicking effects of BPA and its Cl(x)BPA, further research is needed to explore their combined effects on human health and trends in human exposure.

Use of solid-phase microextraction followed by on-column silylation for determining chlorinated bisphenol A in human plasma by gas chromatography-mass spectrometry.

In this study, a solid-phase microextraction (SPME) method based on poly(acrylate)-coated fibres has been developed for detection and quantification of chlorinated bisphenol A in human plasma due to the need for an assessment of human exposure to them. After desorption of the analytes for 7 min at 300 degrees C, they were directly derivatized in the GC injector port by injection of 2 microL of diluted bis(trimethylsilyl)trifluoroacetamide (BSTFA). The formation of trimethylsilylate derivatives improves the selectivity, sensitivity and performance of the chromatographic properties obtained when the analytes are directly separated. Quantification was carried out using single-ion monitoring (SIM). The respective chloroderivative molecular ions appear at 406, 440, 474 and 508 m/z; whereas the base peaks corresponding to a loss of a methyl group in all cases appear at 391, 425, 459 and 493 m/z for mono-, di-, tri- and tetrabisphenol A, respectively. Deuterated bisphenol A (BPA-d16) was used as an internal standard. The method was applied to the determination of Cl-BPA, Cl2-BPA, Cl3-BPA and Cl4-BPA at very low concentration levels in plasma. Recovery efficiencies were close to 100% in all cases.

Nonylphenol and octylphenol in adipose tissue of women in Southern Spain.

Alkylphenols (APs) and AP ethoxylates are environmental contaminants with endocrine disrupting activities in wildlife and humans. They have been largely used in industrial, agricultural, and domestic applications. Despite strong concerns about the consequences of human exposure to endocrine disrupters, little information is available on the presence in humans of compounds such as APs. The aim of the present study was to determine 4-nonylphenol (NP) and 4-octylphenol (OP) residues in adipose tissue of non-occupationally exposed women living in Southern Spain. NP was detected in 100% (n=20/20) and OP in 23.5% (n=4/20) of samples, with median levels of 57 and 4.5 ng g(-1) adipose tissue, respectively. Body mass index emerged as a determinant of exposure since it was associated with NP levels (p=0.041). Adipose tissue NP and OP levels are similar to the few data previously published in other countries. This is the first report on NP and OP levels in a population in Southern Spain. Further research is needed to determine trends in human exposure to these compounds and to investigate their consequences.