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• 25

  July

  LC-MS/MS Analysis of Urinary Free Cortisol and Cortisone wit...

  Cortisol is a steroid hormone synthesized from cholesterol by a multienzyme cascade in the adrenal glands. It is the main glucocorticoid in humans and plays a critical role in glucose metabolism and immune response regulation. Cortisone, a downstream metabolite of cortisol, is measured in conjunction with cortisol to help diagnose various adrenocortical disorders, particularly hypercortisolism (Cushing syndrome). Urinary free cortisol and cortisone levels correlate well with bioactive plasma concentrations and, thus, are important biomarkers. LC-MS/MS is the preferred screening technique for these compounds because it is highly selective and helps eliminate analytical interferences that can affect immunoassay-based methods.

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• 11

  July

  Try This Fast, Accurate LC-MS/MS Method for Folate Deficienc...

  Folate deficiency is considered a risk factor for a wide range of human health problems, including neural tube defects in newborns, cardiovascular diseases, Alzheimer’s disease, and certain forms of cancer. Plasma levels of folic acid and its metabolites (5-formyl tetrahydrofolate and 5-methyltetrahydrofolic acid) are used as biomarkers to diagnose folate deficiency. However, LC-MS/MS methods for folate deficiency biomarkers in plasma can be very challenging because these small, polar compounds are not retained well on traditional reversed-phase LC columns. Retention can be improved using a HILIC method, but in this case, the column must provide strong enough retention to prevent coelution with the phospholipid components in the plasma sample matrix. Although a good sample preparation protocol will help, 100% removal of phospholipids is very difficult, and even low levels of phospholipids can interfere with target analytes, compromise quantitation, and contaminate the MS source.

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• 27

  June

  Definitive EtG/EtS LC-MS/MS Analysis: A Rugged 4-Min Method ...

  Methods for monitoring alcohol consumption biomarkers EtG and EtS are generally limited by poor retention and coelution with matrix interferences, as well as by long analysis times and short column lifetimes. The dilute-and-shoot EtG/EtS LC-MS/MS analysis developed here using the novel Raptor EtG/EtS column easily resolves EtG and EtS from matrix interferences, providing consistent, accurate results for high-throughput labs testing human urine samples for alcohol consumption.

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• 20

  June

  Analysis of Dicamba and 2,4-D by Shimadzu's Triple Quad...

  Shimadzu's app note demonstrates the sensitivity of the LCMS-8060 when analyzing dicamba and 2,4-D in a solution of 100x diluted glufosinate herbicide that contains a high amount of surfactants and other potential mass spec interferants. The LC/MS/MS method was quickly developed with readily available mobile phases. Dicamba in methanol 0.01 and 0.025 ppb had a S/N of 3/1 and 10/1, respectively. 2,4-D in methanol at 0.0001 and 0.001 ppb had a S/N of 13/1 and 90/1, respectively.

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• 13

  June

  BMG's POLARstar Omega Multi-Mode Plate Reader Performs ...

  Mitochondrial dysfunction is central to the pathogenesis of acute pancreatitis as well as other diseases including ischemia-reperfusion injury of the heart, brain and kidney, muscular dystrophies and neurodegeneration. Mitochondrial dysfunction is the result of a sudden increase in permeability of the inner mitochondrial membrane (IMM), via persistent opening of a multi-protein channel known as the mitochondrial permeability transition pore (MPTP) . This allows uncontrolled proton flow across the IMM and unregulated flux of water, ions and solutes up to 1.5 kDa into and out of the mitochondrial matrix. This results in loss of inner mitochondrial-membrane potential, which is essential for ATP production, disruption of calcium homeostasis, swelling of mitochondria and of the outer mitochondrial membrane (OMM). Eventually cells start dying through necrosis in an uncontrolled manner. Therefore, MPTP could be an attractive target for maintenance of mitochondrial  function and cell deat

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