To develop a method to determine selenite and selenate in spiked environmental water by coupling ion chromatography (IC) with single quadrupole mass spectrometry
In AN003644, we developed a method to measure TOF in FCM using combustion-ion chromatography (C-IC). This application proof note demonstrates the determination of TOF in FCM using an enhanced C-IC system. The Thermo Scientific™ Cindion™ C-IC System combines the Thermo Scientific™ Dionex™ Inuvion™ IC System with the Thermo Scientific™ Cindion™ Combustion/Absorption Module, which minimizes PFAS contamination sources and includes a compact Z-fold combustion tube alongside full system control via Thermo Scientific™ Chromeleon™ Chromatography Data System (CDS) software.
Per- and polyfluoroalkyl substances (PFAS) is the collective name for over 14,000 synthetic fluorinated compounds. In addition to their extensive presence, PFAS compounds are persistent and bioaccumulate. Consequently, PFAS compounds are an environmental contamination concern. Toxicological studies of several PFAS compounds indicate the potential for acute to chronic effects impacting reproductive health. In this application, EPA Method 1621 is implemented on the Thermo Scientific Cindion C-IC designed for more efficient combustions and to minimize contamination sources.
A time and labor-saving online sample preparation workflow by amino acid derivatization in the autosampler's needle is presented for medium and highly complex sample matrices (beverages, food, and fertilizers) analyzed at one external and two in-house laboratories. Robust and reproducible method performance, column stability over several hundred injections, and applicability at different instrument tiers are highlighted.
This technical note explores the advantages of using relative standard error (RSE), weighted least squares (WLS) approximations, and inverted calibrations to enhance calibration quality in chromatography. By optimizing calibration curves through quadratic fitting, offset adjustments, and suitable weighting factors (such as 1/Amount²), the calibration process can be significantly improved, resulting in lower RSEs and better overall calibration quality. Incorporating RSE as an evaluation tool offers a deeper understanding of calibration reliability.
