Table 2.

Recovery, detection limits, and quality assurance for isoflavones and lignan polyphenols in human urine samples

Compound	Quantification (confirmation value)	Recovery (%) and (reproducibility, RSD %) (n = 10)	Instrument detection limita (pg)	Method detection limitb (ng/mL)
Equol	386 (371)	103.2 (9.4)	60	20
Daidzein	398 (383)	98.9 (7.3)	100	28
Enterodiol	410 (500)	94.7 (9.2)	2	0.6
Enterolactone	442 (263)	97.3 (10.0)	10	3
D6-daidzein	404 (389)	–	–	–

RSD Relative standard deviation

^a1-μl injection

^b0.5-mL urine sample