Nexera Mikros Applications
While the results of quantification of vitamin D metabolites using LC/MS/MS are more reliable than other methods, in metabolite measurement, the vitamin D is lack of easily ionizable functional groups and pose assay sensitivity challenges mainly for quantification of low-abundance metabolites such as 1,25(OH)2 di-hydroxyvitamin D and 24,25(OH)2 di-hydroxyvitamin D. To overcome this sensitivity problem, It is effective to perform analysis with micro-flow LC/MS/MS. The comparison between micro-flow LC/MS/MS and semimicro-flow LC/MS/MS for the analysis of standard solutions of Vitamin D metabolites shown a 3 to 5 fold improvement in the ratios of signal/noise.
The micro-flow LC/MS/MS system resulted effective in providing better signal intensity also for the quantitation of antiarrhythmic agents that are usually monitored in plasma, due to their narrow therapeutic window and inter individual variability. The increase of the sensitivity when using micro-flow rates was 5 fold for Verapamil and 4 fold for Nor-Verapamil in the ratios of signal/noise.
- Nexera™ Mikros and nSMOL™ Antibody BA Kit -
nSMOL (nano-surface and molecular orientation limited proteolysis) is a proprietary, ground-breaking process that enables selective proteolysis of the Fab region of antibodies using trypsin-immobilized nanoparticles. Fab-derived peptides are quantified via MRM measurement on a high-sensitivity mass spectrometer. The Nexera Mikros system achieved signal intensities 12 times higher than with conventional flow rates, with a corresponding lower limit of detection of 0.025 μg/mL and good linearity. The Nexera Mikros system is ideal for low-level quantitation of peptides by LCMS.
The following is an example of antibody drug analysis in plasma. The plasma spiked with trastuzumab was pretreated using nSMOL Antibody BA Kit.
In the analysis of signature peptides deriving from trastuzumab, Nexera Mikros provides a dynamic range of 0.00763 - 62.5 μg/mL, good linearity with R2 > 0.99, and excellent accuracy of 101.0% (average).
The intra-day reproducibility of this trastuzumab-derived-peptide analysis is summarized in the table below.
These results show an excellent reproducibility, with both of accuracy and precision within 20% at LLOQ and within 15% even at other concentrations.
|QC set1 ＊2||QC set2＊2|
Intra-Day Reproducibility Evaluation Results from QC Samples
*1: This curve is drawn on logarithmic scale.
*2: QC sets 1 and 2 were analyzed over a 2-day period, with each set of concentrations analyzed five times.