Table 2.

Accuracy and precision (intra and inter) of the method for the analysis of terephthalate metabolites, calculated from the analysis (n=5) of urine spiked at 4 different concentrations (0.5, 20, 40 and 100 ng/mL).

	TPA			mMTP			mETP			mTBTP			mBzTP			mEHTP
Spiked (ng/mL)	Mean (ng/mL)	RSD (%)	Accur. (%)	Mean (ng/mL)	RSD (%)	Accur. (%)	Mean (ng/mL)	RSD (%)	Accur. (%)	Mean (ng/mL)	RSD (%)	Accur. (%)	Mean (ng/mL)	RSD (%)	Accur. (%)	Mean (ng/mL)	RSD (%)	Accur. (%)
Intra-day (n=5)
0.5	-*	-	-	0.47	2.7	94	0.58	2.1	116	0.56	4.3	112	0.43	5.1	86	-*	-	-
20	21.2	6.2	106	22.7	9.6	114	18.1	1.4	90.5	17.3	3.2	86.5	20.2	3.4	101	23.4	4.8	117
40	43.1	2.8	108	36.2	6.2	90.5	39.1	5.8	97.8	36.8	4.1	92	35.5	3.1	88.8	41.9	2.2	105
100	96.4	12.2	96.4	98.1	5.1	98.1	108	4.2	108	92.6	9.4	92.6	98.2	2.3	98.2	109	3.6	109
Inter-day (n=5)
0.5	-*	-	-	0.44	3.6	88	0.56	0.7	112	0.53	1.2	106	0.49	0.6	98	-*	-	-
20	20.8	3.7	104	21.9	4.7	110	18.8	5.4	94	18.2	3.9	91	19.1	2.7	95.5	22.1	3.7	111
40	41.5	2.1	104	36.4	5.9	91	40.2	6.6	101	38.5	5.4	96.3	36.9	6.4	92.3	43.7	6.2	109
100	94.6	8.4	94.6	97.5	11	97.5	104	1.9	104	88.7	6.9	88.7	101	3.5	101	105	12.1	105
LOD	0.85			0.12			0.05			0.03			0.04			1.25
LOQ	2.8			0.4			0.17			0.12			0.15			3.75

Where,

^*-not measured due to high background;

RSD: Relative standard deviation; Accur.: Accuracy (or recovery); LOD: Limit of detection; LOQ: Limit of quantification.