Table IV.

Matrix Stability (% Difference) for NOMG, OMG, NOM, 6α-Oxycodol, 6β-Oxycodol, NOC and OC in Urine

	48 h	1 week	2 weeks	3 weeks	1 month
	Room temperature	5 ± 4°C	5 ± 4°C	5 ± 4°C	−20 ± 10°C
Analyte	(% difference, n = 6)	(% difference, n = 6)	(% difference, n = 6)	(% difference, n = 6)	(% difference, n = 6)
NOMG	−11%	−1%	10%	10%	18%
OMG	−8%	7%	4%	2%	5%
NOM	−4%	2%	11%	23%	−4%
αOCL	−3%	4%	6%	1%	3%
βOCL	−4%	2%	3%	1%	3%
NOC	−5%	8%	14%	−4%	3%
OC	−5%	−1%	−4%	−5%	−3%

Concentrations for OM were below limit of quantitation.