Optimization of total vaporization solid-phase microextraction (TV-SPME) for the determination of lipid profiles of Phormia regina, a forensically important blow fly species

Determination of BTEX Compounds in Contaminated Water Using the Novel Vacuum-Assisted-Total Vaporization SPME Method and GO-APTES Fiber

A novel and reliable microextraction technique was used for the fast determination of benzene, toluene, ethylbenzene and xylenes (BTEX) from contaminated water without any extra steps for the preparation or extraction of the aqueous sample. Vacuum-assisted-total vaporization-solid-phase microextraction (SPME) eliminated one of the partitioning steps in conventional headspace SPME and caused an increase in the sensitivity and speed of the method. A home-made graphene oxide/3-aminopropyl-triethoxysilane nanocomposite SPME fiber was synthesized and used as the extraction phase for efficient extraction. Several crucial parameters were optimized, such as the vaporization time and temperature, extraction time and desorption conditions. At the optimum experimental conditions, a linear wide range calibration curve over a wide range of 1-5,000 ng mL-1 and a relative standard deviation (n = 6) of 6.6-7.3% were obtained. The result of the determination of BTEX as a human health risk from real samples, using the proposed method, revealed an acceptable agreement with a valid method.

Detection of ɣ-hydroxybutyric acid (GHB) and ɣ-butyrolactone (GBL) in alcoholic beverages via total vaporization solid-phase microextraction (TV-SPME) and gas chromatography-mass spectrometry

Total Vaporization Solid-Phase Microextraction (TV-SPME) relies on the same technique as standard SPME but completely vaporizes a sample extract, and analytes are sorbed directly from the vapor phase. On-fiber derivatization may also be performed using TV-SPME, where the fiber is first exposed to the headspace of a vial containing the derivatization agent, then exposed to a new vial containing the sample. ɣ-Hydroxybutyric acid (GHB) and ɣ-butyrolactone (GBL) are drugs of concern in that they may be used in drug facilitated sexual assault by surreptitiously spiking them into a victim's beverage. These drugs cause sedation, memory loss, and are difficult to detect in biological samples. One challenge in their analysis is that they can interconvert in aqueous samples, which was demonstrated in samples allowed to stand at room temperature for long periods. A volume study of GBL in water was performed with volumes ranging from 1 to 10,000 µl to compare the efficacy of TV-SPME, headspace SPME, and immersion SPME. Lastly, water, beer, wine, liquor, and mixed drinks were spiked with either GHB or GBL with realistic concentrations (mg/ml) and microliter quantities were analyzed using a TV-SPME Gas Chromatography-Mass Spectrometry method. The GBL volume study demonstrated an increased sensitivity in GBL detection when TV-SPME was utilized. Additionally, GHB and GBL were identified in various beverages at realistic concentrations. Overall, TV-SPME is beneficial because it requires no sample preparation and uses smaller sample volumes than immersion and headspace SPME.

A Systematic Review of Solid-Phase Microextraction Applications in the Forensic Context

Since the introduction in 1990, the solid-phase microextraction (SPME) technology has brought significant progress in many fields of forensic sciences due to the versatility of this fast and solventless alternative to conventional extraction techniques. A systematic review about SPME applications in forensic context from January 1995 to June 2018 was carried out according to systematic review guidelines. The majority of the reviewed articles (40/133) aimed to identify drugs (cannabinoids, cocaine, opiates, amphetamines, simultaneous detection of different drugs of abuse, prescribed drugs); 29 of the 133 articles focused on the investigation of fatalities; 28 of the 133 papers used headspace SPME technique for the identification of markers of chronic alcohol abuse. Sixteen papers involved this technique for the isolation of volatile organic compounds for the human odor profile and 20 concerned forensic applications regarding living people. Solid-phase microextraction was preferably employed in the headspace mode and many kinds of fibers were employed, although polydimethylsiloxane was the most adaptable to many forensic realities. Gas chromatography/mass spectrometry was more frequently used, probably for the well-established coupling with SPME. Most of the papers validated their method to harmonize the scientific approaches of procedures development. Good outcomes are reported on biological material collected from living people as well as on cadaveric samples. The results obtained by most of the studies about alcohol biomarkers on scalp hair have been adopted by the "Society of Hair Testing" to demonstrate abstinence over a pre-defined time period and to assess chronic excessive alcohol consumption.