3.3. Method validation
Deuterium-labeled three internal standards and a mixture of
seven n-nitrosamines were spiked into the control samples, then
extracted and concentrated in the saturated solution of sodium
chloride at 80
°C for 30 min by HS-SPME method. To evaluate the
method, linearity, recovery, and MDL of n-nitrosamines in control
samples were investigated. A typical total ion chromatogram of
target n-nitrosamines extracted from the spiked cosmetic samples
is given in Fig. 5. No signi
ficant interferences were observed in the
selected ion chromatogram (Fig. 5a) although large amounts of
matrix interferences were contained (Fig. 5b).