Matrix Compound % Extraction efficiency (mean ± C.I.) 162.2 ng/mL 973.2 ng/mL Plasma Citalopram 90.9 ± 14.6 101.5 ± 23.7 Desipramine 68.9 ± 6.6 92.2 ± 24.5 Hair Citalopram 33.9 ± 10.4 38.9 ± 4.2 Desipramine 36.6 ± 12.7 36.3 ± 7.1 C.I: Confidence Interval

Table 5: Extraction efficiency, in percentage, of the extraction of the citalopram and desipramine in plasma and hair at two concentration levels.