Separation and Determination of Amitriptyline and Nortriptyline in Biological Samples Using Single-Drop Microextraction with GC

The combination of liquid phase microextraction (LPME) based on a single drop and gas chromatography flame ionization detector (GC-FID) was used for separation and determination of amitriptyline and nortriptyline in human plasma and urine samples. The sample solution was kept alkaline (pH 12), then a microdrop of organic solvent (isooctane) was suspended in the donor solution; after extraction, the organic microdrop was injected into the GC-FID. Experimental LPME conditions were optimized. Finally, the enrichment factors (89.5–139.0), the relative standard deviation (RSD%, n = 5) 1.1–8.5, linearity ranges (0.05–20 μg mL−1), and the limits of detections (0.01, 0.02 μg mL−1) for selected drugs were evaluated.