Matrix effect management in liquid chromatography mass spectrometry: the internal standard normalized matrix effect

Area of Science:

• Analytical Chemistry
• Biochemistry
• Pharmacology

Background:

• Liquid Chromatography-Mass Spectrometry (LC-MS) is a widely used technique for its high sensitivity and selectivity.
• Matrix effects (ME) remain a significant challenge in LC-MS, potentially compromising analytical accuracy.
• Optimal internal standards (ISs), often stable-isotope labeled, are crucial for mitigating ME but may not always be feasible due to cost or availability.

Purpose of the Study:

• To comprehensively review and discuss current techniques for evaluating, reducing, and counterbalancing matrix effects in LC-MS.
• To investigate the inter-lot variability of ME and the effectiveness of different internal standards in correcting these effects.
• To provide a standardized approach for managing ME during method validation.

Main Methods:

• Review and critical discussion of existing methodologies for matrix effect assessment and mitigation.
• Evaluation of the correcting power of various internal standards, including both isotope-labeled and non-labeled options.
• Development of a flowchart for robust matrix effect management, incorporating the concept of internal standard normalized ME.

Main Results:

• Identified and analyzed various techniques currently employed to address matrix effects in LC-MS.
• Highlighted the importance of investigating inter-lot variability of ME and the performance of chosen ISs.
• Proposed a systematic flowchart to guide researchers in managing matrix effects, emphasizing the 'internal standard normalized ME'.

Conclusions:

• Effective management of matrix effects is essential for reliable LC-MS results.
• A standardized approach, as outlined in the proposed flowchart, can enhance the robustness of LC-MS methods.
• Further consensus on the best practices for evaluating internal standards in the context of matrix effects is needed.