Ultrasensitive assay for three polyphenols (catechin, quercetin and resveratrol) and their conjugates in biological fluids utilizing gas chromatography with mass selective detection
Gj. Soleas et al., Ultrasensitive assay for three polyphenols (catechin, quercetin and resveratrol) and their conjugates in biological fluids utilizing gas chromatography with mass selective detection, J CHROMAT B, 757(1), 2001, pp. 161-172
The concentrations of three polyphenols ((+)-catechin, quercetin and trans-
resveratrol) in blood serum, plasma and urine, as well as whole blood, have
been measured after their oral and intragastric administration, respective
ly, to humans and rats. The method developed for this purpose utilized ethy
l acetate extraction of 100 mul samples and their derivatization with bis(t
rimethylsilyl)trifluoroacetamide (BSTFA) followed by gas-chromatographic an
alysis on a DB-5 column followed by mass selective detection employing two
target ions and one qualifier ion for each compound. Total run time was 17
min with excellent resolution and linearity. The limits of detection (LOD)
and quantitation (LOQ) were an order of magnitude less than for any previou
sly published method, being 0.01 mug/l and 0.1 mug/l, respectively, for all
compounds. Recovery at 1 mug/l and 10 mug/l was >80% in all instances but
one, and was >90% in 50%. Imprecision was acceptable at 0.25 and 1.0 mug/l,
concentrations below the LOQ of previous methods. Aglycones released from
conjugates after hydrolysis were easily measurable. Optimal conditions for
hydrolysis were established. After oral administration of the three polyphe
nols to humans, their conjugates vastly exceeded the concentrations of the
aglycones in both plasma and urine. Concentrations peaked within 0.5-1.0 h
in plasma and within 8 h in urine. During the first 24 h, 5.1% of the (+)-c
atechin and 24.6% of the trans-resveratrol given were recovered in the urin
e (free plus conjugated). This method can be proposed as the method of choi
ce to assay these polyphenols and their conjugates in biological fluids. (C
) 2001 Elsevier Science B.V. All rights reserved.