A new method for determining the endocrine disrupting substance 4-nonylphenol (technical grade=mixture of isomers, 4-NP) from water samples has been developed by using 4-(2,6-dimethylhept-3-yl)phenol (4-sec-NP) as model compound. This branched monoalkylphenol is shown to serve as internal standard (IS) for the determination of technical 4-nonylphenol. To the best of our knowledge, 4-(2,6-dimeth...

Laboratory oxidation studies have identified a large number of oxygenated organic compounds that can be used as tracers to understand sources and oxidation chemistry of atmospheric particulate matter. Quantification of these compounds in ambient environments has traditionally relied on low-time-resolution collection of filter samples followed by offline sample treatment with a derivatizing agen...

8-hydroxyguanine (8-OH-Gua) is one of many lesions generated in DNA by oxidative processes including free radicals. It is the most extensively investigated lesion, due to its miscoding properties and its potential role in mutagenesis, carcinogenesis and aging, and also to the existence of analytical methods using HPLC and gas chromatography mass spectrometry (GC/MS). Some studies raised the pos...

RATIONALE To provide a simple one-step derivatization procedure for the analysis of a wide variety of amino acids in human hair by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatization is already widely used outside the IRMS community, is applicable to a variety of functional groups, and provides products that...

The main goal of this work was to quantify the detection of colistin at low levels in urine samples through the practical application of mixed surfactant micellar electrokinetic chromatography-laser-induced fluorescence (MEKC-LIF) analysis method using its advantage of sensitivity and to examine direct injection of biological samples. Colistin (polymyxin E) has neither strong UV chromophore nor...

with Krebs–Henseleit cycle and polyamine synthesis.1–3 It was reported that their high concentration levels in plasma and urine were indicative in diagnoses of some congenital metabolic disorders like cystinuria or hyperlysinemia.2–4 Thus, the selective determination of ornithine and lysine might be more valuable for the diagnoses of these disorders. An amino acids analyzer based on derivatizat...