5 Minute Analysis of Vitamin D in Serum by LC/MS/MS

• High sensitivity improves low level accuracy in matrix.
• 5 minute analysis time speeds up sample throughput.
• Excellent selectivity for vitamin D minimizes matrix interference.

Monitoring of vitamin D levels in patients is important for the prevention and control of disease. Vitamin D, specifically 25-hydroxy vitamin D, plays a critical role in controlling calcium and phosphate levels in the body. If these levels are not adequately controlled, bone conditions such as rickets in children or osteoporosis in adults may occur. 25-hydroxy vitamin D is a hydrophobic, fat soluble vitamin that is absorbed like a fat in the intestines. It is commonly used to diagnose conditions that interfere with fat absorption, such as Crohn's disease. Since vitamin D analysis is one of the most commonly run procedures in clinical labs, high throughput, high sensitivity analytical methods are desirable. Conventional techniques for vitamin D analysis, based on immunoassay or LC/UV, often lack adequate sensitivity, specificity, and speed; thus, interest in LC/MS/MS methods is growing. Here we establish conditions for routine vitamin D testing by LC/MS/MS which result in highly symmetric peaks that elute in just 5 minutes.

1ng Limit of Detection for Acidic/Neutral or Basic Drugs on New Rxi™-5ms Column

• New stationary phase, inert to acidic or basic drugs.
• Unique deactivation allows 1ng LOD.
• Column technology specially developed for GC/MS.

GC/MS is considered the standard for confirming the presence of abused drugs in body fluids, including acidic drugs (e.g., methaqualone), neutral drugs (e.g., phenobarbital), and basic drugs (e.g., methamphetamine). These methods are well established, and the positive identifications that mass spectral data generate are accepted as confirming evidence in courts of law. The accepted stationary phase for these analyses is a 5% phenyl / 95% methyl polysiloxane phase, because it provides the best selectivity for separating the drugs and their metabolites. Unfortunately, not all 5% phenyl columns provide the inertness needed to accurately quantify low concentrations of reactive acidic or basic drugs.