Evaluation of Solid-Phase Microextraction Desorption Parameters for Fast GC Analysis of Cocaine in Coca Leaves

Abstract

By its simplicity and rapidity, solid-phase microextraction (SPME) appears as an interesting alternative for sample introduction in fast gas chromatography (fast GC). This combination depends on numerous parameters affecting the desorption step (i.e., the release of compounds from the SPME fiber coating to the GC column). In this study, different liner diameters, injection temperatures, and gas flow rates are evaluated to accelerate the thermal desorption process in the injection port. This process is followed with real-time direct coupling a split/splitless injector to a mass spectrometer by means of a short capillary. It is shown that an effective, quantitative, and rapid transfer of cocaine (COC) and cocaethylene (CE) is performed with a 0.75-mm i.d. liner, at 280 degrees C and 4 mL/min gas flow rate. The 7-microm polydimethylsiloxane (PDMS) coating is selected for combination with fast GC because the 100-microm PDMS fiber presents some limitations caused by fiber bleeding. Finally, the developed SPME-fast GC method is applied to perform in less than 5 min, the quantitation of COC extracted from coca leaves by focused microwave-assisted extraction. An amount of 7.6 +/- 0.5 mg of COC per gram of dry mass is found, which is in good agreement with previously published results.

A configuration for cooling assisted organic solvent coated thin film microextraction after dispersive liquid-liquid microextraction method: A microextraction method for ultra-trace analyzing of volatile sample

“…In 1990, Pawliszyn and Arthur [ 8 ] presented SPME as a cheap and simple method, without solvent elution of the extracted analyte. However, the important drawbacks of the SPME method are the negligible extraction phase, memory effect, the short lifetime of the fiber, mechanical instability of the fiber, release of the sorbent, high expensive of the commercial fibers, and high extraction time [ [9] , [10] , [11] ]. In 2003, a new SPME approach named TFME was introduced by Bruheim et al [ 12 ].…”

Identification of the Active Odors From Illicit Substances for the Development of Optimal Canine Training Aids

“…Over the past few years, SPME have shown to be an excellent alternative for sample introduction in GC. Not only this combination reduces the timeresponse delivery but also the costs of operation in numerous domains(78). Perhaps its high efficiency and easy coupling with selective and sensitive detectors, gas chromatography remains a frequently selected separation technique(78).The key component for the development of training aids for canine detection has been the identification of the VOCs (signature odor(s)) released from the parent substances.…”

“…Not only this combination reduces the timeresponse delivery but also the costs of operation in numerous domains(78). Perhaps its high efficiency and easy coupling with selective and sensitive detectors, gas chromatography remains a frequently selected separation technique(78).The key component for the development of training aids for canine detection has been the identification of the VOCs (signature odor(s)) released from the parent substances. It is known canines alert to a chemical(s) component in the headspace of the samples and not the parent drug itself however, the question is still which component in the headspace the canines alert to.…”