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Simplified method for the measurement of plasma alkylresorcinols: Biomarkers of whole‐grain intake
Author(s) -
RodríguezMorató Jose,
Jayawardene Sarah,
Huang Neil K.,
Dolnikowski Gregory G.,
Galluccio Jean,
Lichtenstein Alice H.,
Matthan Nirupa R.
Publication year - 2020
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8805
Subject(s) - chemistry , chromatography , protein precipitation , detection limit , triple quadrupole mass spectrometer , analytical chemistry (journal) , crossover study , whole grains , biomarker , selected reaction monitoring , mass spectrometry , food science , tandem mass spectrometry , biochemistry , medicine , alternative medicine , pathology , placebo
Rationale Consumption of whole grains is negatively associated with cardiovascular disease (CVD) risk but quantification of whole‐grain intake is challenging. Alkylresorcinols (ARs) are biomarkers of whole‐grain intake. Current methods for AR quantification involve a time‐consuming multi‐step separation process that hampers applicability in large‐scale studies. Methods We developed a streamlined method to quantify ARs in human plasma based on protein precipitation and direct injection into an ultra‐high‐performance liquid chromatograph coupled to a quadrupole time‐of‐flight mass spectrometer operating in atmospheric pressure chemical ionization negative ion mode. Results Separation of five major ARs was achieved, with linearity in the 5 to 550 nmol/L range and a lower limit of detection (LOD) of 0.5 nmol/L and quantification (LOQ) of 5 nmol/L. The within‐run and between‐run precision and accuracy were below 15%, and recoveries above 90%. Once validated, the method was applied to measure concentrations of plasma ARs in subjects who participated in a randomized, crossover trial evaluating the effect of carbohydrate type on CVD risk factors. The unrefined carbohydrate diet with the highest fiber content resulted in the highest plasma AR concentration (93 ± 78 nmol/L), and was significantly different ( p <0.01) from lower fiber diets (18 ± 26 nmol/L and 19 ± 26 nmol/L, simple and unrefined carbohydrate, respectively). Conclusions This method offers a simplified approach to measure concentrations of plasma ARs as an objective biomarker of whole‐grain intake that can be applied to large‐scale cohort studies.