The Role of Septum Inertness in Minimizing Analyte Degradation in LC-MS

Aug 2, 2021 · Adsorption of analytes on metal surfaces was investigated in LC. • We demonstrated the loss of acidic analytes on metal frits used in LC columns. • Conditioning techniques were useful to mitigate the analyte loss. • Chemically modified LC hardware offers benefits for analysis of oligonucleotides.

Dec 8, 2022 · The use of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) aids the separation of the analyte (s) of interest from matrix components, improving sensitivity and

the LC/MS interface, unwanted compounds compete with analytes for ionization and can cause inconsistent matrix effects that are detrimental to quantitative LC/MS/MS. If not separated from the analytes, some conjugated metabolites break down in the interface so that analyte concentration is overestimated. LC/MS/MS practitioners must use caution in

the column, and finally to the detector. All parts in this flow path play a key role in influencing the inertness of the flow path. Active sites in the flow path can lead to the degradation or adsorption of active analytes, resulting in poor linearity of calibration curves and loss of sensitivity. Therefore, it is critical to deactivate the

Mass spectrometry (MS) analysis of proteins measures the mass-to-charge ratio of ions to identify and quantify molecules in simple and complex mixtures. MS has become invaluable across a broad range of fields and applications, including proteomics. The development of high-throughput and quantitative MS proteomics workflows within the last two

May 17, 2021 · While the LC system is operated at ambient pressures, the mass spectrometer is operated under vacuum and the two are coupled through an interface. As the column eluent flows into the interface, the solvent is evaporated by applying heat and the analyte molecules are vaporized and ionized. This is a crucial step as the mass spectrometer is only

The thermal-spike model proposes that the ejection of intact molecules is attributed to poor vibrational coupling between the matrix and analyte, which minimizes vibrational energy transfer from the matrix to the vibrational modes of the analyte molecule, thereby minimizing fragmentation.

Part 2 examines the important role of mobile phase components, specifically the ionic modifiers. In this article, the LC-MS/ MS optimization for analysis of spice cannabinoids is demonstrated using a range of mobile phase additives for increased analyte response and selectivity. A four-pronged approach leveraging HPLC column selectivity

Dec 13, 2016 · Careful assessment of the effects of time and storage conditions on the integrity of the analytes (i.e., drugs and metabolites) is necessary to minimize degradation or other types of loss that result in the dissociation between the analytical result and the analyte concentration in the patient's blood at the time of sampling.

First, achieving reliable quantitation by LC-MS depends not only on correct use of the instrumentation but also on correct development and use of the entire analytical method. We have, therefore, included extensive advice on aspects such as sample preparation and calibration strategies.

• Especially for low boiling analytes • “Cold trapping” is a version of sample re-focusing for high boiling analytes • Occurs when the starting oven temperature is 150 °C below the boiling point of analytes of interest • Condenses the analytes on the head of the column • Results in better peak shapes

they impart little or no heat to the analyte molecules, LC and LC/MS-based methods can be applied to most organic compounds. Sample types range from small pharma-ceutical compounds to large proteins. Because it is a much more widely applicable method than GC/MS, LC/MS is suitable for the analysis of large, polar, ionic, thermally unstable and

Feb 16, 2022 · Small deviations from an optimized sample preparation protocol can induce variations in mass intensity and spatial localization of analytes affecting the validity of the results. High-quality tissue collection and preservation are essential to limit analyte degradation and maintain the integrity of the tissue [22, 23].

LC/MS system Why and when to use LC/MS The use of LC-MS in many application areas within analytical science continues to grow almost exponentially. Listed below are some pointers as to the applicability of both HPLC as a separative technique and MS as a means of detecting analyte species. HPLC separations

Interference testing falls into two categories: direct testing of the effect of specific substances on analyte concentration, and evaluation of unidentified interferences arising from sample matrix and anything added to it, i.e., matrix effects.