Internal standard response variations during incurred sample analysis by LC-MS/MS: Case by case trouble-shooting

Area of Science:

• Bioanalysis
• Analytical Chemistry
• Pharmacokinetics

Background:

• Internal standard (IS) response variability impacts quantitation accuracy in bioanalytical methods.
• Incurred sample matrices and drug formulations often cause variable IS responses.
• Maintaining study integrity and avoiding economic loss necessitates monitoring IS response variations.

Purpose of the Study:

• To highlight the importance of monitoring internal standard (IS) response variations in bioanalysis.
• To present practical troubleshooting examples for addressing IS response variability in incurred samples.
• To provide insights for developing more reliable bioanalytical methods.

Main Methods:

• Analysis of incurred samples using various bioanalytical methods.
• Troubleshooting twelve practical examples of IS response variations.
• Identification of root causes including human error, equipment malfunction, and matrix effects.

Main Results:

• Common causes of IS response variability identified: human error, equipment issues, incorrect materials, matrix effects, and method-inherent problems.
• Twelve diverse troubleshooting scenarios detailed.
• Practical insights gained from analyzing incurred samples.

Conclusions:

• Proactive monitoring and rapid root cause analysis of IS response variations are essential for reliable bioanalysis.
• Troubleshooting practical examples aid in developing robust and dependable bioanalytical methods.
• Addressing IS variability ensures data integrity and supports study objectives.