Let’s take a look at one of the more irritating issues in LC/MS method development: signal loss. I’m not talking about signal attenuation, which can be much more convoluted to diagnose; but rather a complete loss of signal – nothing, not even a blip on your TIC. So where do we begin?
What's the process behind tuning our analytes to the mass spectrometer’s optics? And why is that so important?
Urine samples are composed of many interferents which can cause ion-suppression or ion-enhancement when analyzing by mass spec. Build up of these matrix components over multiple sample injections can lead to loss of signal in the mass spec and even unexpected changes in your chromatographic separation. We are going to discuss why not performing adequate sample prep can be detrimental for your analyses.
A prime objective of bioanalytical sample preparation is to achieve high analyte recovery in low elution volumes, with rapid delivery of clean extracts that support robust high sensitivity analysis to meet goals for detection limits. What's best between conventional solid phase extraction (SPE) and microelution SPE?
Solid phase extraction (SPE) is frequently used for sample clean up, trace enrichment (pre-concentration of the sample), or a combination of both prior to analysis. But can solid phase extraction be an effective tool when bioanalysis demands higher sensitivity and reproducibility with decreasing sample volumes? In theory, SPE can be used for targeted extractions with ultra-high concentrations. As we will see, putting this into practice requires miniaturization of SPE extraction using sorbent beds with optimal formats that minimize elution volume to maximize detection and quantitation power.
Highly sensitive techniques such as LC-MS/MS are enabling analytical laboratories to generate more data on more analytes in more samples, in less time, at a lower cost, and using smaller sample volumes. Achieving this performance involves pushing the limits of detection and quantitation with high levels of sensitivity and reproducibility that are only possible with high quality samples.
Most clinical chemists have developed a blood, serum or plasma assay using a protein crash because it is inexpensive and generally removes proteins that interfere with detection or the analysis in some way. But is this always true?
This is a question that I am often asked by very smart people that just haven’t had time to learn the process. An optimized sample preparation method is critical for an accurate, specific, robust clinical LC-MS/MS assay. A good sample prep method can improve accuracy and precision, provide longer LC column lifetime, and keep your LC-MS/MS system clean.
