Author: Sharon Lupo and Frances Carroll
Published By: Restek Corporation
Year of Publication: 2017
Protein precipitation is frequently used to minimize matrix impact when analyzing biological samples. However, the effects of highly organic protein precipitation sample extracts on LC peak shape can negatively impact accurate quantification. Dilution or further sample preparation steps are often used to minimize these effects; however, here we show that direct injection of sample extracts is a viable option that can be used to prevent peak distortion, while avoiding the time and variability associated with additional sample preparation.
Restek’s line of Resprep® sample preparation products has expanded to include 96-well protein precipitation (PPT) plates. New Resprep® PPT3 96-well plates offer highly efficient protein removal with built-in, drip-free membrane and 3-way versatility for filtration, so you can prepare serum, plasma, and other biological samples using the name you have long trusted for quality, cleanliness, and performance.
Resprep® PPT3 96-well plates offer consistently greater than 99% protein removal and drip-free, in-well protein precipitation for a minimum of 24 hours—with no fear of backflushing or contamination. A dual-layer membrane with different porosities in each layer prohibits clogging and speeds up filtration, and using our recommended solvent-first method streamlines sample preparation even further.
Resprep® PPT3 96-well plates are also incredibly versatile. The 2.0 mL deep wells are suitable for mixing by vortex or pipette, and these 96-well plates can be used to increase throughput in general filtration applications. Best of all, PPT3 96-well plates are compatible with all common filtration devices: vacuum manifold, positive pressure manifold, and centrifugation.
Order your Resprep® PPT3 96-well plates today at www.restek.com/PPT3
Author(s): Jason S. Herrington
Published By: Analytical Chemistry
Issue: 85 (16)
Year of Publication: 2013
Abstract: The costly damage airborne trimethylsilanol (TMS) exacts on optics in the semiconductor industry has resulted in the demand for accurate and reliable methods for measuring TMS at trace levels (i.e., parts per trillion, volume per volume of air [pptv] [ng/m3]). In this study I developed a whole air canister-based approach for field sampling trimethylsilanol in air, as well as a preconcentration gas chromatography/mass spectrometry laboratory method for analysis. The results demonstrate clean canister blanks (0.06 pptv [0.24 ng/m3], which is below the detection limit), excellent linearity (a calibration relative response factor relative standard deviation [RSD] of 9.8%) over a wide dynamic mass range (1–100 pptv), recovery/accuracy of 93%, a low selected ion monitoring method detection limit of 0.12 pptv (0.48 ng/m3), replicate precision of 6.8% RSD, and stability (84% recovery) out to four days of storage at room temperature. Samples collected at two silicon wafer fabrication facilities ranged from 10.0 to 9120 pptv TMS and appear to be associated with the use of hexamethyldisilazane priming agent. This method will enable semiconductor cleanroom managers to monitor and control for trace levels of trimethylsilanol.