A Simple Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Measurement of Cortisol Level in Human Saliva

Table 1

Extraction recovery of cortisol and internal standard (IS) from saliva.

Nominal concentration; (ng/ml)	Spiked-before-extraction		Spiked-after-extraction		†Recovery; ()
Cortisol	Mean	SD	Mean	SD
0.5	973	76	1029	15	95
1.5	1652	131	1910	178	86
50	49728	4814	53252	4358	93
90	109762	9774	115761	4087	95
IS 20	103554	15923	109630	17990	94

represents mean peak area of 4 replicates and † mean peak area in spiked-before-extraction samples divided by mean peak area in spiked-after-extraction samples x100. SD: standard deviation.