The following question and answer were taken from LCGC Europe's "CE Currents" column (1). How should I approach method development? If possible request any details of sample stability, pKa, and solubility in different solvents and pH ranges. Information on solvents used in HPLC can also be useful.
The following question and answer were taken from LCGC Europe's "CE Currents" column (1).
How should I approach method development?
If possible request any details of sample stability, pKa, and solubility in different solvents and pH ranges. Information on solvents used in HPLC can also be useful.
Initially assess the use of a 1:10 dilution of the running buffer as the optimum choice — this maximizes stacking effects but still maintains stable current traces and avoids the possibility of injection or equipment failures.
A quick test of solvent applicability is to prepare samples in various solvents. A few drops of each sample solution can be added to aliquots of buffer. If the buffer goes cloudy when the drops are added then the sample has precipitated in the buffer and this solvent is probably a poor choice.
(1) K. Altria, LCGC Europe, April 2008.
Questions?
LCGC technical editor Steve Brown will answer your technical questions. Each month, one question will be selected to appear in this space, so we welcome your submissions. Please send all questions to the attention of "Ask the Editor" at lcgcedit@lcgcmag.com We look forward to hearing from you.
Determining Neurotransmitters in Spinal Cords with UHPLC
February 18th 2025Researchers at Jilin University (Changchun, China) developed a highly sensitive, rapid, and accurate method for analyzing neurotransmitters (NTs) in rat spinal cord tissue. Ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) in conjunction with ultra-ionic liquid dispersive liquid-liquid microextraction (UA-MIL-DLLME) were used to extract NTs for analysis.
The Next Frontier for Mass Spectrometry: Maximizing Ion Utilization
January 20th 2025In this podcast, Daniel DeBord, CTO of MOBILion Systems, describes a new high resolution mass spectrometry approach that promises to increase speed and sensitivity in omics applications. MOBILion recently introduced the PAMAF mode of operation, which stands for parallel accumulation with mobility aligned fragmentation. It substantially increases the fraction of ions used for mass spectrometry analysis by replacing the functionality of the quadrupole with high resolution ion mobility. Listen to learn more about this exciting new development.
Revolutionizing LC-MS with Next-Gen Separation for Cyclic Peptide Analysis
February 17th 2025Cyclic peptides, known for their stability and high specificity, are promising therapeutic agents in the fight against cancer, infections, and autoimmune diseases. However, developing effective cyclic peptides presents numerous challenges, including poor pharmacokinetics, efficacy, and toxicity. Traditional methods like liquid chromatography tandem-mass spectrometry (LC-MS/MS) often struggle with resolving isomeric linear peptide metabolites, posing significant risks in safety, efficacy, and regulatory approval. In this paper, Komal Kedia, PhD, will share how she leveraged MOBIE’s high-resolution ion mobility-mass spectrometry (IM-MS) system to achieve a 72% reduction in run times, 200% greater resolving power, and enhanced accuracy in identifying “soft spots” prone to enzymatic degradation.