The ion-pair solid-phase extraction (SPE) of 4-alkylphenols followed by derivatization with pentafluoropyridine is demonstrated. Under alkaline conditions, the 4-alkylphenols could be efficiently adsorbed on a C18 SPE cartridge conditioned with an ion-pair reagent, tetra-n-hexylammonium bromide. The ion pairs, ammonium phenolates, formed on the C18 solid phase, were eluted with a solvent containing the derivatizing reagent, pentafluoropyridine, and completely derivatized during the elution. After optimization of the adsorption and derivatization, we established a method for the determination of the 4-alkylphenols in water samples. The method showed good linearity between 20 and 1000 ng (200-10,000 ng for nonylphenol). By processing 20-ml samples, the method detection limits (MDL) were in the range of 5.2-8.9 ng/l for the 4-alkylphenols (76 ng/l for nonylphenol). To evaluate its applicability to a real aqueous matrix, several river water samples were analyzed.
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http://dx.doi.org/10.1016/j.chroma.2005.01.103 | DOI Listing |
Molecules
November 2024
Department of Natural and Environmental Sciences, Faculty of Science, Academic Assembly, University of Toyama, Toyama 930-8555, Japan.
Concerns over the emergence of steroid hormones as pollutants in water have grown. Steroid hormone compounds present challenges in the simultaneous detection of total residual hormones owing to their analogous structures and diverse types. In this study, we established a rapid and high-throughput continuous online method based on solid phase extraction (SPE) coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of 61 hormone components, including 48 glucocorticoids, 1 mineralocorticoid, 4 androgens, and 8 progesterones, in water.
View Article and Find Full Text PDFAnalyst
July 2024
Department of Developmental Neurology, Medical University of Gdansk, 7 Dębinki Str., PL-80-952, Gdańsk, Poland.
The study aimed to analyze nusinersen metabolites in the cerebrospinal fluid samples using ion-pair reversed-phase ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Three different sample preparation methods were tested for extraction and purification, but solid phase extraction appeared to be the most suitable, allowing a significant sample enrichment (40-fold). This step was necessary to detect and identify metabolites of nusinersen in the cerebrospinal fluid.
View Article and Find Full Text PDFHeliyon
May 2024
School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Yantai University, Yantai, 264005, China.
A hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC/MS/MS) method was developed and validated for the quantitative analysis of the fully phosphorothioate modified oligonucleotide nusinersen. HILIC/MS/MS method is more robust and compatible with mass spectrometry than ion pair reversed-phase liquid chromatography-tandem mass spectrometry (IP-RP-LC/MS/MS). Various types and concentrations of additives and different pH of mobile phase affected the mass spectrometry response, chromatographic peak shape and retention of nusinersen.
View Article and Find Full Text PDFBioanalysis
March 2024
School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Yantai University, Yantai, 264005, China.
The fully phosphorothioate-modified oligonucleotide (OGN) nusinersen has low ionization efficiency in the negative ion mode, resulting in a low mass spectrometry response. There have been no relevant reports on developing a LC-MS method for the determination of nusinersen by optimizing mobile phase composition. Mobile phase additives comprised of 15 mM triethylamine/25 mM 1,1,1,3,3,3-hexafluoro-2-propanol with a pH of 9.
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