1. Department of Pharmaceutics and Pharmacodynamics, University of Illinois at Chicago, 833 S. Wood St., Chicago, IL 60612, USA
2. U.S. Drug Testing Laboratories, 1700 S. Mount Prospect Rd., Des Plaines, IL 60018
3. National Board of Forensic Medicine, Linköping, Sweden

Seven point standard curves for FN and 7AFN were prepared by spiking 50 mg aliquots of pulverized drug free hair. The range of the standard curves was 500 fg/mg - 100 pg/mg for 7AFN and 2.5 pg/mg - 100 pg/mg for FN. In addition, two levels of control hairs were prepared for FN (15 and 80 pg/mg) and 7AFN (3 and 40 pg/mg). Our lab received 3 hair samples from suicide cases involving FN and one alleged rape case. All samples were washed in deionized water, dried and pulverized. Internal standards, FN D₇ (100 pg/mg) and 7AFN D₇ (20 pg/mg) were added to 50 mg aliquots of hair, standards and controls. MeOH (3 ml) was added to each vial and they were sonicated for 1 h. MeOH was decanted and 0.1N HCl was added (3 ml). The specimens were incubated for 18 hours at 50°C. The fractions were combined and mixed mode solid phase extraction was performed. Final elution of the drugs was achieved using methylene chloride:isopropanol:NH₄OH (78:20:2, v/v/v). Extracts were evaporated to dryness, and derivatized with HFBA (50 ml). HFBA was evaporated and EtAc (25 ml) was added. A Hewlett Packard GC-MS system comprising a 6890 GC and a 5973 MSD detector (CI with methane) was operated in SIM mode with splitless injection. For FN m/z 313, for FN D₇ m/z 320, for 7AFN m/z 459, for 7AFN D₇ m/z 466 ions were monitored.

Standard curves for FN and 7AFN had correlation coefficients of 0.998 and 0.997, respectively. All precision and accuracy values were within acceptable limits. Two samples were negative for FN and 7AFN (including alleged rape), and two were positive (case 1: FN 23 pg/mg, 7AFN 26.07 pg/mg; case 2: 7AFN 48.61 pg/mg). In the second case only 9 mg of gray hair was available for analysis.