Table 6.

Stabilities of DHT, α-diol, and β-diol under various test conditions (n = 5).

Condition	Temperature	Sample	Recovery ± SD (%)
			DHT		α-diol		β-diol
			6h	24 h	6h	24 h	6h	24 h
Bench-top	23 °C	Stock solutiona	102 ± 1	100 ± 1	100 ± 2	99 ± 3	101 ± 2	100 ± 1
		Stock solutionb	99 ± 2	101 ± 1	100 ± 3	98 ± 4	99 ± 3	99 ± 2
Bench-top	23 °C	Low QCc	94 ± 1	92 ± 3	93 ± 2	94 ± 4	91 ± 6	92 ± 3
		High QCc	92 ± 2	91 ± 4	91 ± 4	92 ± 2	94 ± 5	93 ± 5
Auto sampler	4°C	Low QC	97 ± 3	99 ± 5	101 ± 2	99 ± 3	97 ± 4	99 ± 3
		HighQC	96 ± 5	98 ± 4	102 ± 4	100 ± 3	101 ± 1	98 ± 4
3 Freeze-thaw cycles	−20°C to 23 °C	Low QC	100 ± 3	98 ± 3	99 ± 2	104 ± 2	97 ± 5	99 ± 3
		HighQC	101 ± 5	102 ± 2	95 ± 4	100 ± 4	101 ± 4	104 ± 2
Long-term. (40 days)	−70°C	Low QC	93 ± 3		94 ± 5		95 ± 6
		HighQC	97 ± 5		98 ± 6		92 ± 5

^aThe concentration of the stock solution was 1.00 mg/mL, which was measured by serial dilution to 0.150 ng/mL in the mobile phase.

^bThe concentration of the stock solution was 1.00 mg/mL, which was measured by serial dilution to 40.0 ng/mL in the mobile phase.

^cThe concentrations of sera low and high QCs were 0.150 ng/mL and 40.0 ng/mL, respectively.