Biochemical testing for pheochromocytoma is a diagnostic challenge due both to the highly variable nature of this rare catecholamine-producing tumor and the technical demands required for accurate and reliable laboratory tests of catecholamine excess. In this issue of Clinical Chemistry, de Jong et al. (1 ) describe a high-throughput automated liquid–chromatography-tandem mass spectrometry (LC-...

Due to the low percentage of fetal DNA present in maternal plasma (< 10%) during early gestation, efficient extraction processes are required for successful downstream detection applications in non-invasive prenatal diagnostic testing. In this study, two extraction methods using similar chemistries but different workflows were compared for isolation efficiency and percent fetal DNA recovery. Th...

OBJECTIVE To establish a routine for the extraction of the total levels of CoQ10 in human plasma through the Ultra High Performance Liquid Chromatography (UHPLC). METHODS Two extraction protocols were tested: a) methanol: hexane and b) 1-propanol. The following parameters were analyzed: extraction temperature (19ºC and 4ºC), extraction tubes (glass and polypropylene), and surfactants (SDS, Tr...

A three dimensional ion optical code IBSimu is being developed at the University of Jyväskylä. So far the plasma modelling of the code has been restricted to positive ion extraction systems, but now a negative ion plasma extraction model has been added. The plasma model has been successfully validated with simulations of the Spallation Neutron Source (SNS) ion source extraction both in cylindri...

Gabapentin is an anticonvulsant widely used in the treatment of epilepsy. No peculiar chromophore is available on the gabapentin moiety for direct analysis by absorption spectrophotometry. A sensitive spectrophotometric method for the determination of gabapentin in bulk, pharmaceutical formulations and human plasma has been developed. In this method, gabapentin directly derivatized with vanilli...

An HPLC assay is described for the determination of Z-butylidenephthalide (Z-Bdph) in plasma. Plasma samples were cleaned up by extraction with 2% chloroform in n-hexane. Z-Bdph was separated on a normal-phase silica column with a mobile phase of chloroform-n-hexane (1:1). The limit of quantitation with UV detection at 254 nm for Z-Bdph in plasma was 0.01 microgram/ml. The recovery of Z-Bdph by...

A method is described for the determination of nonesterified fatty acids in plasma. Extraction is at least 98% efficient, and losses during subsequent stages are corrected for by the use of an internal radioactive standard. The method is suitable for reference purposes rather than for routine determinations. Higher values are obtained than by other methods of analysis, and it is suggested that ...

Oxylipins are potent lipid mediators. For the evaluation of their biological roles, several LC-MS based methods have been developed. While these methods are similar, the described sample preparation procedures for the extraction of oxylipins differ considerably. In order to deduce the most appropriate method for the analysis of non-esterified oxylipins in human plasma, we evaluated the performa...

A general-purpose three-dimensional (3D) simulation code IBSIMU for charged particle optics with space charge is under development at JYFL. The code was originally developed for designing a slit-beam plasma extraction and nanosecond scale chopping for pulsed neutron generator, but has been developed further and has been used for many applications. The code features a nonlinear FDM Poisson's equ...