1,721,033 research outputs found
Development and validation of a LC/MS/MS method for simultaneous quantification of oxcarbazepine and its main metabolites in human serum.
Full text linkA fast, sensitive and specific LC/MS/MS method for the simultaneous analysis of oxcarbazepine (OXC), 10-hydroxycarbazepine (MHD) and
trans-diol-carbazepine (DHD), in human serum, has been developed and validated. Serum drugs were extracted by C8 solid-phase cartridges
(SPE) and separated in less than 3 min on a C18 reverse-phase column using an isocratic elution. A tandem mass spectrometer, as detector, was
used for quantitative analysis in positive mode by a multiple reaction monitoring. Calibration curves, obtained on two ranges of concentration
(0.78–50 mg/L for MHD and 0.078–5.0 mg/L for OXC and DHD), showed correlation coefficients (r) better than 0.997. Within day and between
days quality controls imprecision, as CV%, ranged from 0.3 to 4.6% and from 1.9 to 5.8%, respectively. Cyheptamide (CYE) was used as internal
standard. No detectable carry-over and no relevant cross-talk and matrix effect occurred. Samples from 24 treated patients were analysed and drug
serum concentrations obtained by this method are in agreement with those of other methods and also are well correlated (r = 0.88) in comparison to
our routine HPLC-UV method. Based on the analytical results and short run time, the method is suitable to support routine analysis of therapeutic
drugs monitoring from human serum of treated patients or for pharmacokinetic studies
Orotic acid quantification in dried blood spots and biological fluids by hydrophilic interaction liquid chromatography tandem mass spectrometry.
Full text linkDetermination of Brain Extracted Lipids by Thin-Layer Chromatography – Imaging Desorption Electrospray Ionization (TLC-Imaging DESI).
No full textFast, sensitive and specific method for serum quantification of oxcarbazepine and its two metabolites, 10-hydroxycarbazepine and transdiol-carbazepine by LC/MS/MS.
No full textNEUTRAL LOSS ANALYSIS OF AMINO ACIDS BY DESORPTION ELECTROSPRAY IONIZATION USING AN UNMODIFIED TANDEM QUADRUPOLE MASS SPECTROMETER.
Full text linkA new method to analyze free amino acids using desorption electrospray ionization (DESI) has been
implemented. The method is based on the neutral loss mode determination of underivatized amino
acids using a tandem quadrupole mass spectrometer equipped with an unmodified atmospheric
interface. Qualitative and quantitative optimization of DESI parameters, including ESI voltage,
solvent flow rate, angle of collection and incidence, gas flow and temperatures, was performed for
amino acids detection. The parameters for DESI analysis were evaluated using a mixture of valine,
leucine, methionine, phenylalanine and tyrosine standards. A few microliters of this mixture were
deposited on a slide, dried and analyzed at a flow rate of 2mL/min. The optimal ionization response
was obtained using laboratory glass slides and an equivalent solution of water/methanol doped with
2% of formic acid. The method specificity was evaluated by comparing product ion spectra and
neutral loss analysis of amino acids obtained either by DESI or by electrospray ionization flow
injection analysis (ESI-FIA). To evaluate the quantitative response on amino acids analyzed by DESI,
calibration curves were performed on amino acid standard solutions spiked with a fixed amount of
labelled amino acids. The method was also employed to analyze free amino acids from blood spots,
after a rapid solvent extraction without other sample pretreatment, from positive and negative
subjects. The method enables one to analyze biological samples and to discriminate healthy subjects
from patients affected by inherited metabolic diseases. The intrinsic high-throughput analysis of
DESI represents an opportunity, because of its potential application in clinical chemistry.....
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