Rapid metabolic screening of early zebrafish embryogenesis based on direct infusion-nanoESI-FTMS

Analytical BioScience

Tuberculosis causes highly conserved metabolic changes in human patients, mycobacteria‑infected mice and zebrafish larvae

Solid state NMR/Biophysical Organic ChemistryAnimal science

Eggshell strength: The causes of egg breakage in relation to nutrition, management and environment. B Part two

Een rantsoen met 4% oesterschelpen en 3.5% krijt garandeert een voldoende opname voor calcium gedurende de gehele dag. Voor een goede eiproduktie met voldoende schaalsterkte is 0.3% Fosfor en 3.5% calcium aan te bevelen. Toevoeging van 50 ppm Vitamine C is aan te bevelen bij hoge temperatuur en relatieve vochtigheid. Goede hokinrichting en goed management kunnen eischaalbreuk in gunstige zin beinvloede

Gas pressure assisted microliquid-liquid extraction coupled online to direct infusion mass spectrometry: a new automated screening platform for bioanalysis

In the field of bioanalysis, there is an increasing demand for miniaturized, automated, robust sample pretreatment procedures that can be easily connected to direct-infusion mass spectrometry (DI-MS) in order to allow the high-throughput screening of drugs and/or their metabolites in complex body fluids like plasma. Liquid-Liquid extraction (LLE) is a common sample pretreatment technique often used for complex aqueous samples in bioanalysis. Despite significant developments that have been made in automated and miniaturized LLE procedures, fully automated LLE techniques allowing high-throughput bioanalytical studies on small-volume samples using direct infusion mass spectrometry, have not been matured yet. Here, we introduce a new fully automated micro-LLE technique based on gas-pressure assisted mixing followed by passive phase separation, coupled online to nanoelectrospray-DI-MS. Our method was characterized by varying the gas flow and its duration through the solvent mixture. For evaluation of the analytical performance, four drugs were spiked to human plasma, resulting in highly acceptable precision (RSD down to 9%) and linearity (R(2) ranging from 0.990 to 0.998). We demonstrate that our new method does not only allow the reliable extraction of analytes from small sample volumes of a few microliters in an automated and high-throughput manner, but also performs comparable or better than conventional offline LLE, in which the handling of small volumes remains challenging. Finally, we demonstrate the applicability of our method for drug screening on dried blood spots showing excellent linearity (R(2) of 0.998) and precision (RSD of 9%). In conclusion, we present the proof of principe of a new high-throughput screening platform for bioanalysis based on a new automated microLLE method, coupled online to a commercially available nano-ESI-DI-MS.Analytical BioScience