Matrix Effect Variability in Urine Samples from Different Cohorts and Implications on LC-ESI-MS Mycotoxin Biomarker...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Biomarker Analysis

Background:

• Matrix effects (ME) are a significant challenge in liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) analysis.
• The complexity and variability of the urine matrix complicate accurate quantification, particularly in multi-analyte methods.

Purpose of the Study:

• To investigate the extent and variability of matrix effects in urine samples.
• To evaluate the impact of matrix effects on the quantification of 11 mycotoxins using stable isotope-labelled standards (SIL-IS).

Main Methods:

• Analysis of urine samples from two distinct cohorts (Bangladeshi women and Swedish children) using LC-ESI-MS.
• Quantification of 11 mycotoxins utilizing stable isotope-labelled standards (SIL-IS).
• Investigation of factors influencing matrix effects, including age, sex, urine density, and creatinine concentration.

Main Results:

• Significant differences in ME were observed between the Bangladeshi and Swedish cohorts for eight out of 11 mycotoxins.
• High intra-cohort ME variability was found, with interquartile ranges (IQR) exceeding 15% for 14 analyte-cohort combinations.
• Sterigmatocystin showed a maximum IQR of 318% in the Bangladeshi cohort, severely impacting quantification.
• Urine density and creatinine concentration correlated with ME, particularly for polar analytes exhibiting signal suppression.

Conclusions:

• Matrix effects in urine analysis are highly variable between and within individuals and cohorts.
• Stable isotope-labelled standards are crucial for accurate mycotoxin quantification in complex urine matrices.
• Urine density and creatinine concentration are key factors influencing matrix effects, necessitating careful sample handling for samples with extreme values.