2 research outputs found
Using Procedural Blanks to Generate Analyte-Specific Limits of Detection for Persistent Organic Pollutants Based on GC-MS Analysis
Several
methods are used to generate a limit of detection for organic
pollutants measured by gas chromatography–mass spectroscopy
(GC-MS); all have theoretical and practical drawbacks. The current
project investigated two common existing methods (statistical and
empirical) for applicability to chromatographic properties from real
samples, comparing these with a new proposed method using procedural
blanks to estimate a minimum detectable peak area. Weaknesses of all
three methods are discussed. The proposed method was superior to other
examined methods in that it provided analyte-specific limits of detection
linked to the recovery of mass-labeled internal standards for every
analyte within every sample. Other identified quality assurance benefits
included the following: enhanced protection against false positives;
providing a sensitivity performance metric across batch, analyst,
and instrument; enabling chemists with discretionary decisions specific
to every analyte regarding detectability and interferences; and some
strengths of both statistical and empirical techniques without major
drawbacks of either. In marine sediment samples, the proposed method
of calculating the limit of detection increased reporting of trace
level (low- to subppb) GC-MS data for polychlorinated biphenyls (PCBs),
polybrominated diphenyl ethers (PBDEs), organochlorine pesticides
(OCPs), and polycyclic aromatic hydrocarbons (PAHs) by up to 400%
compared with the statistical method
LipidQC: Method Validation Tool for Visual Comparison to SRM 1950 Using NIST Interlaboratory Comparison Exercise Lipid Consensus Mean Estimate Values
As
advances in analytical separation techniques, mass spectrometry
instrumentation, and data processing platforms continue to spur growth
in the lipidomics field, more structurally unique lipid species are
detected and annotated. The lipidomics community is in need of benchmark
reference values to assess the validity of various lipidomics workflows
in providing accurate quantitative measurements across the diverse
lipidome. LipidQC addresses the harmonization challenge in lipid quantitation
by providing a semiautomated process, independent of analytical platform,
for visual comparison of experimental results of National Institute
of Standards and Technology Standard Reference Material (SRM) 1950,
“Metabolites in Frozen Human Plasma”, against benchmark
consensus mean concentrations derived from the NIST Lipidomics Interlaboratory
Comparison Exercise