การสกัดด้วยตัวดูดซับของแข็งร่วมกับเทคนิคแก๊สโครมาโทกราฟี–เฟลมไอออไนเซชั่นสำหรับการตรวจวัดสารปลอมปนที่มีฤทธิ์ทางเภสัชวิทยาในผลิตภัณฑ์ลดน้ำหนัก

Abstract

The aim of this thesis is to develop a solid phase extraction method with gas chromatography–flame ionization technique for determination of pharmacologically active adulterants, including methamphetamine (MA), caffeine (CAF), sibutramine (SIB), fluoxetine (FLU), and tramadol (TAM) in suspected slimming products. Hydrophilic– lipophilic balance or HLB sorbent material was used for extraction and purification of sample. For Oasis HLB® extraction, a 1.00 mL aliquot of sample was alkalinized to pH 12 and was added with an 15% w/v sodium chloride prior to undergoing solid phase extraction. The sample solution was loaded onto the cartridge which was preconditioned with 1.00 mL methanol and 1.00 mL deionized water. The cartridge was washed with 1.00 mL of 20% (v/v) methanol: water mixture. The target analytes were eluted with 1.00 mL 70% (v/v) methanol: water mixture containing 2% acetic acid and 1.00 mL acetonitrile. Under optimum conditions with gas chromatographic technique, the proposed method provides the extraction efficiency of five pharmacologically active adulterants in the range of 81–113%. All analytes were well separated within 13.9 min. The proposed method provided the linearity at a concentration of 0.5–100 mg L-1 (r2> 0.9987–0.9997) for five pharmacologically active adulterants. Limits of detection and quantification were 0.05–0.09 mg L-1 and 0.15– 0.30 mg L-1, respectively. The intra-day and inter-day precisions were 0.39–9.24% RSD and 0.63–10.88% RSD, respectively. The intra–and inter–day accuracies were 85.36–112.62% and 85.61–106.14%, respectively. The proposed method was then applied for the determination of pharmacologically active adulterants in four different types of slimming products, viz. dietary supplement, herbal slimming product, slimming coffee powder and slimming drink powder. Three slimming products were found to contain SIB in the range of 1.9–248.1 mg L-1 . CAF and FLU were detected in one slimming product. These findings indicate that solid phase extraction method with gas chromatography–flame ionization technique for determination of pharmacologically active adulterants is precise, accurate, and reliable. The sample preparation can clean up sample and provides good extraction efficiency. It would be a useful method to apply in laboratories of the Office of the Consumer Protection and Scientific Crime Detection Center.