Table 4.

Matrix effect, recovery and process efficiency. (n=8 for thiotepa and tepa, n=3 for CP and 4OHCP)

Analytes	Conc. (ng/ml)	Matrix effect			Recovery		PE
		analyte	IS	IS-normalized	analyte	IS	analyte	IS
Thiotepa	Low (3)	108	105	103	86.3	95.9	93.3	101
	Med (80)	105	110	95.5	90.3	95.0	94.6	105
	High (1600)	106	111	95.5	93.4	98.1	99.2	109
tepa	Low (3)	121	119	102	88.3	94.5	107	112
	Med (80)	120	120	100	86.3	92.7	104	112
	High (1600)	111	115	96.5	89.0	93.4	98.8	107
CP	Low (60)	105	98.9	106	107	103	112	102
	Med (800)	101	100	101	103	101	103	101
	High (8000)	108	102	106	90.2	95.9	97.6	97.5
4OHCP	Low (60)	105	98	107	113	107	118	104
	Med (800)	103	100	103	115	102	118	102
	High (4000)	112	104	108	99.3	95.8	111	99.8