The Application Notebook-12-02-2009

The Application Notebook

Cyanide, an environmental contaminant, can cause serious health effects including goiters, hypothyroidism and some neuromuscular diseases. Cyanide wastewater sources include the plating and mining industries, burning of coal and plastics and effluent from publicly owned treatment works (POTW).

Most recently formulated pesticides are smaller in molecular weight and designed to break down rapidly in the environment.

The term ionic liquid refers to organic salts with relatively low melting points (below 100 °C) that usually consist of an organic cation or anion and a counterion, in either organic or inorganic form. Ionic liquids exhibit unique characteristics such as extremely low vapour pressure, excellent thermal stability, electrical conductivity, a high degree of polarity and miscibility with various types of solvents. Ionic liquids have been used as catalysts and solvents in organic chemistry and electrochemistry and as mobile phase modifiers or functionalized stationary phases in separation science.1–3

SPME-GC–MS with on-column injection can be successfully employed for flavour profiling of food samples. The on-column injector of the GC-2010 can be used for SPME without any modifications, only an external ring adapter was used to facilitate the injection. The data can be compared with sensorial data of food.

The free and total content of detrimental glycerol in vegetable oil methyl esters (biodiesel) is of paramount importance for the quality of biodiesel and is, therefore, limited by the US ASTM D 6751 and the European EN 14214 standards. Both regulations currently stipulate gas chromatographic (GC) analysis of free and total glycerol. However, the GC method, apart from being expensive, requires tedious derivatizations and fails for glycerol determinations in coconut or palm kernel oil methyl esters.

The Application Notebook

In the pharmaceutical industry the increased efficiency brought about by new fast chromatography methods needs to be matched by commensurate mass spec capabilities. maXis UHR-TOF is the instrument of choice to keep up with fastest chromatography.

The composition and analysis of fragrance components in home and personal care (HPC) products is very complex and unquestionably time consuming.

The Application Notebook

Catecholamines are important markers for the diagnosis and management of tumour diseases of the sympathoadrenal system. The major catecholamines are dopamine, norepinephrine and epinephrine. Urine tests have shown to be applicable to measure the level of catecholamines in the human body. Various separation methods have been used for the clean-up of catecholamines in biological fluids: solvent extraction, adsorption on alumina, ion-exchange and solid-phase extraction of a diphenylboronic acid-catecholamine complex. From the point of simplicity, reproducibility and automation the last method is the most suitable and can be realized by on-line SPE–LC. Diphenylborate forms a negatively charged complex with the diol groups of catecholamines. These complexes which are strongly retained on a polystyrene-divinylbenzene cartridge in alkaline medium (pH 8.5) can be eluted in a second step from the SPE unit directly onto the HPLC column. The separation of catecholamines is performed in isocratic mode by..

As UPLC users convert or replace their existing HPLC systems with UPLC systems there is a transition period where a method must be run on both platforms. Thus, having the same particle substrate and bonded phases available in HPLC and UPLC particle sizes can significantly ease the burden of method development and transfer from one platform to another. In addition to the ethylene bridged hybrid (BEH) particle, three new high strength silica (HSS) stationary phases for HPLC applications are introduced. Scalability between both column diameter and particle size is demonstrated on both UPLC and HPLC instrumentation.

The Application Notebook

Increase throughput of the HPLC method for triazine herbicides by employing ultra high-speed liquid chromatography at elevated temperature on a heat stable Thermo Scientific Hypercarb column.

The QuEChERS method for pesticide analysis was first introduced by USDA scientists in 2003. The EN method 15662:2007 is a European variation to the QuEChERS method. The method uses acetonitrile extraction, followed by the salting out of water from the sample using anhydrous magnesium sulphate (MgSO4, NaCl and buffering citrate salts to induce liquid–liquid partitioning.

Corn stover is the above-ground portion of the plant minus the kernels and it accounts for a large percentage of the global supply of lignocelluosic biomass available as feedstock for fermentation systems used for biofuel production.

All plant foods are complex mixtures of chemicals including both nutrients and biologically active non-nutrients, referred to as phytochemicals. Soy is known for having high concentrations of several physiologically-active phytochemicals, including isoflavones, phytate (inositol hexaphosphate), saponins, phytosterols and protease inhibitors. The isoflavones are what makes soy unique.

The Application Notebook

According to the FDA policy statement, developing stereoisomeric drugs, each enantiomer should be evaluated.1 As a result, the pharmaceutical industry has escalated its emphasis on the generation of enantiomerically pure compounds before undertaking pharmacokinetic, metabolic, physiological and toxicological evaluations.2 Chiral chromatography, especially SFC, is the most widely used technique for obtaining mg to multigrams of pure enantiomers in drug discovery. In SFC, a combination of supercritical CO2 and polar organic solvent(s), most commonly alcohol, are used as the mobile phase. Because of the higher diffusivity and lower viscosity of supercritical fluid, SFC often provides a 3–8-fold faster separation than normal-phase HPLC. For chiral purification, SFC also offers significant cost savings by reducing organic solvent usage and removal as well as the time and energy required post-purification. As SFC instrumentation continues to improve, SFC has gradually overtaken HPLC as the first choice..