As medical marijuana is more frequently prescribed, patient safety must be ensured. Pesticide residue testing is an important part of assuring safe product is dispensed, but analysis can be extremely challenging due to matrix complexity. The use of QuEChERS, cartridge SPE cleanup, and GCxGC-TOFMS as presented here, produces high-quality quantitative data for this difficult analysis.
The Rtx-Dioxin2 column has a unique selectivity for dioxins and furans, including specificity for 2,3,7,8-TCDD and 2,3,7,8-TCDF. Here we characterize all 136 tetra- through octachlorine dioxins and furans and define all possible coelutions. While commonly used cyanopropyl columns are limited by a low maximum operating temperature of 240°C, the Rtx-Dioxin2 column is stable up to 340°C, extending column lifetime and improving the analyses of dioxins and furans.
Quick, Easy, Cheap, Effective, Rugged, and Safe, the QuEChERS (catchers) method for extracting pesticides from food is based on USDA research and employs a novel dispersive solid phase extraction cleanup (dSPE). QuEChERS methods are convenient, rugged methods that simplify extract cleanup, reduce material costs, and improve sample throughput. Here we demonstrate the effectiveness of QuEChERS sample cleanup using a multiresidue analysis of pesticides on strawberries.
Melamine contamination was implicated in a large pet food recall that occurred in 2007 when animals died after eating contaminated pet food. Here, a modified GC/MS method, based on an FDA method, was used to analyze for melamine & related compounds cyanuric acid, ammelide, and ammeline in dry cat food. Analytes were easily identified by retention time matching and mass spectra.
Conditions are established for analyzing both derivatized and underivatized cholesterol on a highly inert Rxi-5ms column. Methods described include both an isothermal analysis for use when interferences are minimal, but sample throughput is critical, and a temperature program for use when separation of analytes from contaminants or interfering compounds is the primary concern. Results for both derivatized and underivatized samples were highly reproducible.
Concurrent solvent recondensation large volume splitless injection (CSR-LVSI) GC/MS is used here for analyzing pesticides and brominated flame retardants in drinking water based on EPA Method 527. CSR-LVSI allows a time-consuming sample extract concentration step to be eliminated, but can also be used with extract concentration for lower detection limits.
Typically, 1,4-dioxane and nitrosamines are analyzed in drinking water following separate extraction and analysis procedures, such as Methods 521 and 522. However, here we present a combined method that uses large volume splitless injection and GC-MS (SIM) to meet low part-per-trillion detection limits for these compounds in a fraction of the time required when running separate methods.
n-Octane on Res-Sil C packing provides excellent, reproducible separations of volatile hydrocarbons in petroleum products, including the difficult-to-separate saturated and unsaturated C4 compounds. An OPN on Res-Sil C column separates C1-C5 hydrocarbons in half the time required by alternative columns.
Robust Rtx-DHA columns are highly stable and can be run with hydrogen carrier gas under accelerated conditions. The hydrogen-based method for detailed hydrocarbon analysis shown here is twice as fast as traditional approaches, which allows labs to process samples faster and make more profitable decisions during product blending.
The results of a simulated distillation analysis are vitally important to the operation of refineries globally. For the analysis of petroleum samples within the boiling point range from 55.5 ˚C to 538 ˚C, ASTM D2887 is a standard method that has been accepted and is used industry-wide. This application note will demonstrate how a creative use of the Restek GC Accelerator oven insert kit can permit analysts using Agilent 6890/7890 GCs with 100/120 V ovens to successfully migrate from D2887’s slower Procedure A conditions to the accelerated Procedure B conditions without new instrumentation or software, resulting in a 9-minute analysis time that meets all method requirements.
