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Dionex Application Note

A new, efficient, effective, and sensitive sample preparation application for the extraction of the catecholamines epinephrine, norepinephrine, and dopamine from human plasma at significantly low levels using EVOLUTE WCX, a resin-based mixed-mode sorbent with an optimized combination of nonpolar (hydrophobic) and weak cation exchange interactions.

Barbiturates are a class of antidepressants whose abuse and addiction by recreational users has become a widespread problem (www.nlm.nih.gov). In our work we strived to streamline the barbiturate screening process to provide a fast, cost-effective, and reproducible method from start to finish for forensic labs who are involved in high-throughput processing.

International regulations on maximum residue levels (MRLs) of pesticides in food cover hundreds of individual contaminants at the 10 ppb or below range. The analysis of citrus oil for pesticide contamination holds specific challenges.

Endothall is a widely used herbicide for both terrestrial and aquatic weeds. Exposure to endothall in excess of the maximum contamination level (MCL) can cause illness. Endothall is regulated by the U.S.

This application note describes the method for detection of nanogram levels of explosive constituents in seawater samples (e.g., after detonation of unexploded ordnance devices). The improved chromatographic method was developed using the Agilent 1290 Infinity LC Method Development system.

The chiral analysis and purification of proton pump inhibitors (PPIs) has become a popular topic as more of these drugs fall out of patent protection each year. Due to their wide range of enantiomeric selectivity, a set of polysaccharide-based chiral stationary phases (CSPs) was screened to identify methods for the successful enantioseparation of four benzimidazoles; rabeprazole, lansoprazole, omeprazole, and pantoprazole.

The chemicals 2- and 4-methylimidazole (2-MI and 4-MI) are by-products produced during the manufacturing of caramel coloring ingredients used to darken food products such as carbonated beverages and soy sauce.

Anthocyanins are a sub-class of naturally electron deficient and powerful antioxidants called flavonoids that are responsible for the red, orange, and blue coloration in fruits and flowers.

PCBs are a group of synthetic organic chemicals that contain 209 individual compounds (known as congeners) with varying harmful effects. PCBs enter the environment as mixtures containing a variety of individual components.

High performance time-of-flight mass spectrometry (TOF-MS) is applied to the analysis and characterization of complex biological samples. High mass accuracy, high resolution, and accurate relative isotope abundance are all applied to the determination of analytes covering a range of concentrations in complex matrices including plasma and urine. Qualitative and quantitative evaluations are provided and include demonstrations of the impact of high-performance MS on sensitivity and selectivity. The ability to leverage high-performance MS in conjunction with a broad dynamic range in rapid ultrahigh-pressure liquid chromatography (UHPLC) analyses to identify unknowns and to propose putative metabolic biomarkers is demonstrated. The impact of speed of analysis and selectivity to the depth of coverage and accuracy of the analyses are discussed.

Waters Application Note

Glyphosate is a broad-spectrum herbicide widely used around the world. Monitoring of glyphosate in crops and water is mandated in many countries.

A new series on valves and the pivotal role they play in gas chromatography.

This study evaluates the performance of a C18 core-shell phase that incorporates a C18 ligand with iso-butyl side chains. The Kinetex? XB-C18 HPLC/ UHPLC column delivers a fast and effective separation of several common preservatives in cosmetics.

Due to the increasing number of toxic pesticides being used throughout the world, a robust method for positively identifying low levels of multiple classes of pesticides is required. A Zebron? ZB-MultiResidue? column is used with GC–MS to identify over 100 common pesticides.

Dionex Application Note

Testosterone was extracted from human serum by strong anion exchange polymeric SPE and analyzed using a Kinetex C18, 30 ? 2.1 mm, 1.7 ?m column and positive polarity ESI LC–MS-MS system. Kinetex sub-2 ?m core-shell technology offers higher efficiencies than traditional sub-2 ?m columns, producing greater chromatographic resolution, sensitivity, and higher peak capacities.

The Consumer Product Safety Improvement Act of 2008 (CPSIA) requires testing of child care products and toys for selected phthalate esters by GC–MS.

Optical fibers are routinely used in liquid chromatographic detectors as a means of simplifying optical designs. Selection of the appropriate fiber is an important factor in achieving optimal system performance.

With advances in instrumentation and without regulatory method constraints, 1,4-dioxane can be detected at the part-per-billion (ppb) level, despite its poor purge efficiency. This application will manipulate purge and trap, as well as GC–MS parameters, to create a more efficient method to reduce cycle times. This study will utilize a Teledyne Tekmar Atomx Automated Sample Prep System in conjunction with an Agilent 7890/5975 GC–MS. A linear calibration and method detection limits (MDLs) for 1,4-dioxane will be established using this method.

Vitamin D deficiency has become a topic of interest in recent publications (1–3). Vitamin D is present in two forms, Vitamin D3 and Vitamin D2. D3 is produced after ultraviolet light-stimulated conversion of 7-dehydrocholesterol in the skin (3).

Kanamycin and amikacin are aminoglycoside antibiotics used to treat serious bacterial infections. Amikacin is used for infections resistant to other aminoglycosides because it is less susceptible to enzymatic reactions.

Coping with extractables and leachables testing is easier when you have a good understanding of the issues involved. Information from public databases and industry consortia also is invaluable.

Click the title above to open the LCGC North America June 2011 regular issue, Vol 29 No 6, in an interactive PDF format.

Click the title above to open the LCGC North America June 2011 Application Notebook, Vol 29 No s6, in an interactive PDF format.

Gyula Vigh, professor of chemistry and holder of the Gradipore Chair of Separation Science at Texas A&M University, has been selected as the 2011 recipient of the Hungarian Society for Separation Sciences (HSSS) Halász Medal Award recognizing research excellence in the separation sciences.

Claind, Italian manufacturer of gas generators has appointed Jaytee Biosciences as the sole distributor and service agent for their Brezza range of gas generators in the UK and Ireland.