Solid Phase Microextration Research Articles

Comparison of microbiota and volatile organic compounds in milk from different sheep breeds

In this study, we compared the microbiota and volatile organic compounds (VOC) present in the milk obtained from 3 different sheep breeds, namely Merino, Lacaune, and Assaf. Udder milk was collected from 21 animals, 7 from each breed. Bacterial microflora was determined metagenomically by extracting the DNA from the milk and analyzing the V3-V4 region of the 16S rRNA gene. Headspace solid-phase microextraction gas chromatography-mass spectrometry method was used to analyze VOC. The metagenomic analysis revealed (for Merino, Lacaune, and Assaf milk, respectively) Firmicutes (66.32, 69.36, and 57.08%), Actinobacteria (19.09, 7.67, and 19.40%), Proteobacteria (13.76, 21.06, and 22.19%), and Bacteroidetes (0.84, 1.91, and 1.33%) phyla in the milk samples. Lactobacillus was highly abundant in the milk of 3 breeds (29.64, 43.50, and 18.70%). The genera constituting more than 2% of all bacteria in all groups were Jeotgalicoccus (7.19, 5.34, and 10.77%), Enterococcus (5.18, 9.78, and 3.64%), and Corynebacterium (4.08, 3.00, and 13.44%). A total of 32 different VOC were identified by headspace solid-phase microextration analysis with 9, 30, and 24 different compounds from Merino, Lacaune, and Assaf breeds, respectively. Although ketone was the most abundant compound in Merino milk (71.84%), hydrocarbons were the most detected in Lacaune and Assaf milk (37.18% and 55.42%, respectively). A positive correlation was found between acetone, which was detected at the highest level in all groups, with Salinicoccus, Alloiococcus, Psychrobacter, and Dietzia. In addition, a negative correlation was found between the Lactobacillus genus, detected at the highest level in all groups, with methyl cyclopentane, 3-methylheptane, octane, decane, 3,3-dimethyloctane, and dodecane. Thus, differences were observed in the bacterial microflora and VOC in the sheep milk from different breeds under different feeding and breeding conditions.

Solid phase microextraction of organochlorine pesticides in water using MWCNTs-doped polypyrrole coated on steel fiber

The analysis of organochlorine pesticides (OCPs) residues has received an increasing attention in the last decades. Solid-phase microextration (SPME) is a convenient and fast analytical method, which has been widely used for the determination of volatile and semivolatile organic compounds in aqueous samples. The multiwalled carbon nanotubes/polypyrrole composite coating was used for the SPME of OCPs in water samples. The effects of various parameters on the efficiency of SPME process such as extraction time, extraction temperature, ionic strength, desorption time, and desorption temperature were studied. Under optimized conditions, the detection limits for the OCPs varied between 0.051 and 0.39 pg mL-1, the inter-day and intra-day relative standard deviations for various OCPs using a single fiber were 6.5-11.5% and 3.6-11.5, respectively. The linear ranges varied between 0.001 and 1 ng mL-1. The method was successfully applied to the analysis of ground water samples with the recoveries from 86 to 110%.

Comparative assessment of the degradation of 2-methylisoborneol and geosmin in freshwater using advanced oxidation processes

ABSTRACT Traditional methodologies of conventional drinking water treatment are unable to remove some chemical compounds, such as those that cause odor and taste in drinking water. The present work aims to evaluate the efficiency of advanced oxidations processes, using UV radiation, O3 and O3 + UV in the degradation of geosmin (GSM) and 2-methylisoborneol (2-MIB) in synthetic samples. The efficiency of the processes was monitored by Gas Chromatography coupled with Mass Spectrometry using solid phase microextration technique. Experiments were carried out for 45 min with samplings every 15 min. The degradation results showed that UV radiation alone was not efficient for the degradation of both compounds. The fasted decay was observed by the combined use of O3 and UV with an ozone concentration of 15.84 mg L−1. Under these conditions, the final concentration of GSM was below the limit of quantification, so that approximately 99% of the initial concentration was degraded, while 2-MIB was degraded by 95%. With the same O3 concentration without the use of UV radiation, 63% and 65.7% of MIB and GSM, respectively, were removed. Higher efficiency of the treatment was observed with a higher O3 concentration which allows a shorter reaction time.

Development of a Rapid Method for Determination of Main Higher Alcohols in Fermented Alcoholic Beverages Based on Dispersive Liquid-Liquid Microextraction and Gas Chromatography-Mass Spectrometry

Higher alcohols are important flavor compounds in alcoholic beverages. A new method was developed to determinate the main higher alcohols based on dispersive liquid-liquid microextraction (DLLME) coupled with GC/MS. Huangjiu was selected as an example to develop the method. The optimal DLLME parameters were acquired: the sample was diluted one time with water, no pH adjustment was required, 600 μL dichloromethane as extraction solvent, 1.5 mL acetonitrile as dispersant, 3.5 mL of sample volume, 1 min of extraction time and no salt addition. The performance of the method was satisfactory. The results obtained from DLLME were consistent with those from head space solid phase microextration (HS-SPME) and static headspace (SHS). In addition, DLLME is simpler and more time-saving compared with HS-SPME and SHS. These results indicated that the present method is satisfactory and suitable for determination of higher alcohols in Huangjiu, especially for routine inspection and batch analysis.

Cocoa smoky off-flavor: Chemical characterization and objective evaluation for quality control

Cocoa smoky off-flavor is due to inappropriate post-harvest processing and cannot be removed in the subsequent chocolate-manufacturing steps. To date, no reliable analytical method to detect key-analytes responsible for smoky off-flavor in incoming raw material is available. This study aims to develop an analytical method, suitable for quality control, to detect smoky markers. The cocoa volatilome was first profiled by headspace solid phase microextration combined with comprehensive two-dimensional gas chromatography-mass spectrometry from a set of representative smoky and non-smoky samples; advanced fingerprinting revealed the chemicals responsible for the off-flavor. The results served to develop a 1D-GC method suitable for routine application. Ten identified smoky markers were subjected to accurate quantification, thereby defining operative ranges to accept/reject incoming bean samples. On average, these markers are present in smoky samples at 7 to 125 fold concentrations vs. those in non-smoky beans, ranging from 32.5 ng/g for naphtalene to 721.8 ng/g for phenol.

Aerial drone as a carrier for miniaturized air sampling systems

The applicability of an aerial drone as a carrier for new passive and active miniaturized air sampling systems, including solid phase microextration Arrow (SPME Arrow) and in-tube extraction (ITEX), was studied in this research. Thermal desorption, gas chromatography and mass spectrometry were used for the determination of volatile organic compounds (VOCs) collected by the sampling systems. The direct comparison of the profiles of VOCs, simultaneously sampled in air by SPME Arrow system including four different coatings, allowed the elucidation of their adsorption selectivity. A more complex experimental design, involving 20 samples (10 flights) and non-supervised pattern recognition techniques, was needed for the clarification of the same sampling parameters in the case of five ITEX sorbent materials. In addition, ITEX sampling accessories, such as particle, water and ozone traps, were evaluated by comparing the results obtained for air samples simultaneously collected by two ITEX systems, packed with the same sorbent and furnished or not with sampling accessories. The effect of the aerial drone horizontal displacement (HD) on the sampling efficiency was clear in the case of SPME Arrow. The number of detected compounds and their relative peak area values (RPA) revealed a clear increase (4 and 43%, respectively) in comparison with samples collected without drone HD. However, just minor differences were observed in the case of ITEX (2 compounds and 9% of the ∑RPA). In addition, the system was able to provide almost simultaneous passive (SPME Arrow) and active (ITEX) samplings at different altitudes (5 and 50 m), being a good tool for low cost vertical profiling studies (∑RPA decreased over 35% for the samples collected at 50 m). Finally, the successful simultaneous air sampling by SPME Arrow and ITEX systems in two difficult access places, such as boreal forest and wetlands, was demonstrated, resulting in 21 and 31 detected compounds in forest and wetlands by SPME Arrow, and 27 and 39 compounds by ITEX.

Composition analysis of floral scent within genus Camellia uncovers substantial interspecific variations

The great diversity and complexity of floral scent originate from specialized metabolic pathways partly due to the ever-evolving plant and pollinator interaction. However, the diversity of floral scent compositions in plant species remains to be elucidated. Genus Camellia contains a large number of species including several famous ornamental species, and species within the section Theopsis possess distinctive floral scent traits. In this study, we have collected 22 species from Theopsis and performed headspace- solid phase microextration coupled with gas chromatography mass spectrum (HS-SPME-GC–MS) analysis to investigate the scent compositions. In total, we identified 223 volatile compounds belonging to benzenoids, phenyl propanoids, terpenes, and other components. Remarkable interspecific variations in composition and quantity were revealed. We characterized the relationships of different types of volatile compounds by hierarchical clustering and principal component analysis, and showed that small amount of chemicals could affect the scent effects significantly. Moreover, we compared the volatile emission patterns between different floral organ types and developmental stages in Camellia buxifolia. We revealed that stamens emitted more volatiles than petals, and the emission reached the maximum at the stage of flower half opening. This work provides fundamental information for breeding Camellia cultivars with scent traits.

Preparation and analytical application of novel thiol-functionalized solid extraction matrices: From mesoporous silica to hybrid monolithic capillary column

A comprehensively comparative study of thiol-functionalized mesoporous silica and organic-inorganic hybrid monolithic column was reported, aiming at the separation and enrichment of inorganic arsenic. Thiol-functionalized mesoporous silica was synthesized based on the one-step co-condensation method. At the same time, a novel thiol-functionalized organic-inorganic hybrid monolithic column was synthesized using an unconventional ternary weak basic solvent system via one-step sol-gel process. The approach to prepare monolithic column through mild condition remarkably improved delamination phenomenon of thiol-functionalized hybrid monolithic column easily caused by conventional methods. As(III) can be selectively uptaken by the hybrid monolithic column and homemade syringe-based solid phase extraction device containing mesoporous silica through chelation in a wide range of pH, while As(V) cannot, and then the captured As(III) was eluted by 3% HNO3 (v/v) with 0.01 mol L−1 KIO3. Under the optimized conditions, the extraction recoveries were 91–102% and 93–103% for mesoporous silica and monolithic column, respectively. Although both two materials were ideal solid matrices for the removal and speciation analysis of As(III) in environmental waters, the monolith-based solid phase microextration protocol was more fast and reagent-saving than the other, which endued monolithic columns with more application prospects for trace elemental analysis and speciation. Even so, the exploration of mesoporous silica could efficiently pilot the synthesis of monolithic columns.

Biocompatible Surface-Coated Probe for in Vivo, in Situ, and Microscale Lipidomics of Small Biological Organisms and Cells Using Mass Spectrometry.

Lipidomics is a significant way to understand the structural and functional roles that lipids play in biological systems. Although many mass spectrometry (MS)-based lipidomics strategies have recently achieve remarkable results, in vivo, in situ, and microscale lipidomics for small biological organisms and cells have not yet been obtained. In this article, we report a novel lipidomics methodology for in vivo, in situ, and microscale investigation of small biological organisms and cells using biocompatible surface-coated probe nanoelectrospray ionization mass spectrometry (BSCP-nanoESI-MS). A novel biocompatible surface-coated solid-phase microextration (SPME) probe is prepared, which possesses a probe-end diameter of less than 5 μm and shows excellent enrichment capacity toward lipid species. In vivo extraction of living biological organisms (e.g., zebrafishes), in situ sampling a precise position of small organisms (e.g., Daphnia magna), and even microscale analysis of single eukaryotic cells (e.g., HepG2) are easily achieved by the SPME probe. After extraction, the loaded SPME probe is directly applied for nanoESI-MS analysis, and a high-resolution mass spectrometer is employed for recording spectra and identifying lipid species. Compared with the conventional direct infusion shotgun MS lipidomics, our proposed methodology shows a similar result of lipid profiles but with simpler sample pretreatment, less sample consumption, and shorter analytical times. Lipidomics of zebrafish, Daphnia magna, and HepG2 cell populations were investigated by our proposed BSCP-nanoESI-MS methodology, and abundant lipid compositions were detected and identified and biomarkers were obtained via multivariate statistical analysis.

Evolution of potent odorants within the volatile metabolome of high-quality hazelnuts (Corylus avellana L.): evaluation by comprehensive two-dimensional gas chromatography coupled with mass spectrometry.

Within the pattern of volatiles released by food products (volatilome), potent odorants are bio-active compounds that trigger aroma perception by activating a complex array of odor receptors (ORs) in the regio olfactoria. Their informative role is fundamental to select optimal post-harvest and storage conditions and preserve food sensory quality. This study addresses the volatile metabolome from high-quality hazelnuts (Corylus avellana L.) from the Ordu region (Turkey) and Tonda Romana from Italy, and investigates its evolution throughout the production chain (post-harvest, industrial storage, roasting) to find functional correlations between technological strategies and product quality. The volatile metabolome is analyzed by headspace solid-phase microextration combined with comprehensive two-dimensional gas chromatography and mass spectrometry. Dedicated pattern recognition, based on 2D data (targeted fingerprinting), is used to mine analytical outputs, while principal component analysis (PCA), Fisher ratio, hierarchical clustering, and analysis of variance are used to find decision makers among the most informative chemicals. Low-temperature drying (18-20°C) has a decisive effect on quality; it correlates negatively with bacteria and mold metabolic activity, nut viability, and lipid oxidation products (2-methyl-1-propanol, 3-methyl-1-butanol, 2-ethyl-1-hexanol, 2-octanol, 1-octen-3-ol, hexanal, octanal and (E)-2-heptanal). Protective atmosphere storage (99% N2-1% O2) effectively limits lipid oxidation for 9-12months after nut harvest. The combination of optimal drying and storage preserves the aroma potential; after roasting at different shelf-lives, key odorants responsible for malty and buttery (2- and 3-methylbutanal, 2,3-butanedione and 2,3-pentanedione), earthy (methylpyrazine, 2-ethyl-5-methyl pyrazine and 3-ethyl-2,5-dimethyl pyrazine) and caramel-like and musty notes (2,5-dimethyl-4-hydroxy-3(2H)-furanone - furaneol and acetyl pyrrole) show no significant variation. Graphical abstract Comprehensive two-dimensional gas chromatography (GC × GC) coupled with mass spectrometric detection captures hazelnut volatiles signatures while advanced fingerprinting approaches based on pattern recognition enable access to a higher level of information.

Analysis of the flavor of aged spirits made from sweet potato and rice by gas chromatography-mass spectrometry.

Flavor patterns of sweet potato spirits (SPS) made from sul-deot manufactured by sweet potato showed an increasing tendency for aging from 64 to 128weeks. When the SPS was blended with spirits made from sul-deot manufactured by rice in a 7:3 ratio, showing an increase for aging from 16 to 60weeks, using a gas chromatography-mass spectrometry with solid-phase microextration. The main compounds showing increasing tendency of the SPS and blended spirits (BS) were iso-amyl alcohol, n-propanol. Especially, ethyl caprylate, and ethyl acetate increased in SPS. The results were cross-checked by an electronic nose. For the results of SPS in the flavor pattern, a decrease was noted by main ion fragments. For the BS, a decrease was noted. These cross-checked results were useful for controlling quality of aging spirits, especially SPS. Based on these results, it was considered that further experiments are needed to identify key compounds for accurate correlation analysis.

Electrospun decyl-3-methylimidazolium mono bromate/polyamide nanofibers as solid-phase microextraction coating

In the current study, electrospun-based ionic liquid (IL) doped polyamide (PA) nanofibers were prepared and used as the coating material of solid phase microextration device in the fiber geometry. Addition of IL, decyl-3-methylimidazolium mono bromate, increased the conductivity of the PA solution facilitating the electrospining process. The scanning electron microscopy images of decyl-3-methylimidazolium mono bromated/polyamide nanofibers showed the decreased diameter of the nanofibers in the range of 35–160nm compared to the PA nanofiber. The factors affecting the structure of nanofibers (e.g. ratio of decyl-3-methylimidazolium mono bromate to PA, coating time and applied voltage) were studied. In addition, influential parameters of extraction/desorption performance such as ionic strength, extraction time, and desorption time and temperature were studied. The limit of detections and limit of quantifications were obtained in the range of 0.75–0.9 and 2–5ngL−1, respectively, demonstrating high efficiency of the prepared nanofiber. The developed method also showed good repeatability, RSD 4–9% (n=3), for the spiked aqueous solution at concentration level 150ngL−1 of chlorobenzenes, and linearity,R=0.996, in the range of 5–5000ngL−1.

Pollicipes pollicipes as a Biomonitor of PAHs Contamination in Seawaters of the Northwest Coast of Portugal

ABSTRACTSimple, fast, and economic solid phase microextration–gas chromatography–mass spectrometry (SPME–GC–MS) methods were validated for the determination of 8 United States Environmental Protection Agency priority polycyclic aromatic hydrocarbons (PAHs: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene) in coastal seawaters and soft tissues of goose barnacles Pollicipes pollicipes. Under the optimized conditions, the limits of detection ranged from 0.012 to 1.069 ng L−1 and 0.002 to 0.061 µg kg−1 (dry weight basis) for seawaters and soft tissues, respectively. Precision varied between 3.9% and 20.0% for seawaters and between 8.4% and 19.1% for soft tissues, which are acceptable repeatabilities for environmental analyses. Finally, the accuracy of the optimized conditions also showed suitable recoveries, varying between 81.5% and 105.5% in spiked seawater samples and between 88.0% and 103.4% in the standard reference material for organics in mussel tissues (NIST SRM 2977). These methods were applied to a monitoring program performed along the northwest coast of Portugal during four seasons in 2011 in order to assess the levels of these compounds present in coastal waters and in the tissues of goose barnacles, one food resource of high commercial value. The results showed that although the concentrations of PAHs in seawaters and P. pollicipes varied significantly along the coast and between seasons (p < 0.05), in general the concentrations in seawater can be classified as “Class II – Good/Natural Background Concentrations” during the four seasons of 2011. As for the concentrations of PAHs in P. pollicipes, they were positively correlated (p < 0.05) with their concentrations in seawater, indicating that P. pollicipes may be an adequate biomonitor species of PAHs availabilities along the coast of Portugal throughout the year.

Surface-coated wooden-tip electrospray ionization mass spectrometry for determination of trace fluoroquinolone and macrolide antibiotics in water

In this study, a surface-coated wooden-tip electrospray ionization mass spectrometry (SCWT-ESI-MS) method was developed for rapid and sensitive analysis of trace fluoroquinolone and macrolide antibiotics in water. First, a SCWT solid-phase microextration (SPME) probe was prepared, via silanization and sulfonation for modification of a layer of adsorbent containing both C8-chain and sulfo group on the surface of wooden tips. Then, the SCWT-SPME probe was applied for extraction of trace fluoroquinolone and macrolide antibiotics in water. The specially designed adsorbent gave the probe desirable enrichment capacity towards fluoroquinolone and macrolide antibiotics, with enrichment factors of approximately 100–500 folds for six target analytes. After extraction, the loaded SCWT-SPME probe was directly applied for ambient MS analysis. With the application of a high voltage and some spray solvent on the SCWT-SPME probe, analytes enriched on the probe was desorbed and ionized for mass spectrometric analysis under ambient and open-air conditions. The method was sensitive, with limits of detection and quantification of 1.8–4.5 ng/L and 5.9–15.1 ng/L, respectively. The method also showed good linearity, with correlation coefficient values (r2) of no less than 0.9940 for six target analytes. The developed method was successfully applied for the analysis of six fluoroquinolone and macrolide antibiotics in tap and river water samples, and no antibiotic was found in tap water but some antibiotics were detected in river water with concentrations at dozens to hundreds nanogram-per-liter level. Standard addition experiments were also performed, and the obtained recoveries were 89–102% for tap waters and 82–92% for river waters, respectively. All the experimental results demonstrated that our proposed SCWT-ESI-MS method was rapid, sensitive, and reliable for analyzing trace antibiotics in water.

Modified zeolitic imidazolate framework-8 as solid-phase microextraction Arrow coating for sampling of amines in wastewater and food samples followed by gas chromatography-mass spectrometry

In this study, a novel solid phase microextration (SPME) Arrow was prepared for the sampling of volatile low molecular weight alkylamines (trimethylamine (TMA) and triethylamine (TEA)) in wastewater, salmon and mushroom samples before gas chromatographic separation with mass spectrometer as detector. Acidified zeolitic imidazolate framework-8 (A-ZIF-8) was utilized as adsorbent and poly(vinyl chloride) (PVC) as the adhesive. The custom SPME Arrow was fabricated via a physical adhesion: (1) ZIF-8 particles were suspended in a mixture of tetrahydrofuran (THF) and PVC to form a homogeneous suspension, (2) a non-coated stainless steel SPME Arrow was dipped in the ZIF-8/PVC suspension for several times to obtain a uniform and thick coating, (3) the pore size of ZIF-8 was modified by headspace exposure to hydrochloric acid in order to increase the extraction efficiency for amines. The effect of ZIF-8 concentration in PVC solution, dipping cycles and aging temperature on extraction efficiency was investigated. In addition, sampling parameters such as NaCl concentration, sample volume, extraction time, potassium hydroxide concentration, desorption temperature and desorption time were optimized. The Arrow-to-Arrow reproducibilities (RSDs) for five ZIF-8 coated Arrows were 15.6% and 13.3% for TMA and TEA, respectively. The extraction with A-ZIF-8/PVC Arrow was highly reproducible for at least 130 cycles without noticeable decrease of performance (RSD<12.5%). Headspace SPME of 7.5mL sample solution with the fabricated ZIF-8 coated Arrow achieved linear ranges of 1–200ngmL−1 for both TMA and TEA. The limit of quantitation (LOQ) was 1ngmL−1 for both TMA and TEA. The method was successfully applied to the determination of TMA and TEA in wastewater, salmon and mushroom samples giving satisfactory selectivity towards the studied amines.

Chemical investigations of volatile kairomones produced by Hyphantria cunea (Drury), a host of the parasitoid Chouioia cunea Yang

In tritrophic 'plants-herbivores-natural enemies' systems, there are relatively few reports concerning the role(s) of kairomones in pupal parasitism. Chouioia cunea Yang (Hymenoptera: Eulophidae), an endoparasitic chalcid wasp, parasitizes pupae of the fall webworm (Hyphantria cunea Drury). The role of host-related kairomones was investigated using electroantennogram (EAG) and behavioral techniques. Chemicals from some host stages (pupae) and host by-products (frass), induced arrestment behavior of female parasitoids, while chemicals from prepupae, were inactive. Gas chromatography-mass spectrometry analysis of volatiles collected from pupae, frass and prepupae using solid-phase microextration revealed seven compounds with carbon chain lengths ranging from C4 to C20. All of the chemicals elicited significant EAG responses in C. cunea. Y-tube olfactometer bioassays demonstrated a significant positive response of mated female C. cunea to 1-dodecene. These data provide a better understanding of the host location mechanisms of pupal parasitoid.

Extracting Emissions from Air Fresheners Using Solid Phase Microextraction Devices

Families all over the world commonly use air fresheners indoors. In this investigation, needle trap samplers (NTS), which are environmentally friendly analytical devices, are used to sample the gaseous products from three types of lavender fresheners-liquid, granular and oil. NTS are prepared using 60-80 mesh divinylbenzene (DVB) particles in 22 gauge stainless steel needles and utilized to extract indoor organic compounds. This investigation compares the extraction efficiency of NTS with that of commercially available 100-μm polydimethylsiloxane solid phase microextration (PDMSSPME) fiber samplers, when used to sample gaseous emission products from fresheners. The experimental results revealed that 60-80 mesh DVB-NTS outperformed SPME fibers during a 1-hr sampling period, and the main compounds that are extracted by NTS were ethanol, benzene, toluene, ethylbenzene, xylenes, dichloromethane, butenes and pentane. The potential use of small badge-sized or pen-sized NTS for indoor atmospheric and occupational hygiene applications is thoroughly evaluated.

Gaseous Products of Incense Coil Combustion Extracted by Passive Solid Phase Microextraction Samplers

Burning incense indoors is a common behavior in Southeast Asia. In this investigation, needle trap samplers (NTS), a novel, green analytical technology is used for sampling gaseous combustion by-products from sandalwood incense coils. To extract indoor volatile organic compounds (VOCs), two NTS are prepared, one using 60–80 mesh and the other using 100–120 mesh divinylbenzene (DVB) particles packed in 22-gauge stainless steel needles. This work compares extraction efficiency of an NTS and that of a commercially available 100 μm polydimethylsiloxane solid phase microextration (PDMS-SPME) fiber sampler. Experimental results indicated that the 100–120 mesh DVB-NTS performed best among all samplers during a 1 h sampling period. The main extracted compounds were toluene, ethylbenzene, propane, chloromethane, 1,3-butadiene, methanol and dichloromethane. The potential use of small badge-sized or pen-sized NTS for the indoor atmosphere and occupational hygiene applications is addressed.

Detection of "bath salt" synthetic cathinones and metabolites in urine via DART-MS and solid phase microextraction.

A rapid and sensitive method, direct analysis in real time mass spectrometry (DART-MS) was applied to the characterization and semiquantitative analysis of synthetic cathinones and their metabolites in urine. DART-MS was capable of detecting three different cathinones and three metabolites down to sub-clinical levels directly without any sample preparations. The process produced a spectrum within seconds because no extraction or derivatization was required for analysis and the high mass accuracy of the instrumentation allowed analysis without the need for lengthy chromatographic separations. The use of solid phase microextration demonstrated a relative increase in the detectability of both drugs and metabolites, improving the detection signal on average more than an order of magnitude over direct detection, while providing cleaner spectra devoid of the major peaks associated with urine that oftentimes dominate such samples.

Preparation of needle trap samplers to extract air compounds from indoor electric-vaporizing sources

In this study, gaseous benzene, toluene, ethylbenzene, and o-xylene (BTEX) were extracted by passive needle trap samplers (NTS) using divinylbenzene (DVB) particles (mesh sizes 60–80, 80–100, and 100–120, respectively) as packed sorbents. An aspirating pump measured sampling flow rates of NTS, and the relations between BTEX mass and sampling flow rates were sufficient to maintain the extraction performance of these self-designed DVB-NTS. Furthermore, this investigation compared the extraction efficiency of NTS with that of the 100-µm polydimethylsiloxane solid-phase microextration (PDMS SPME) fiber when applied to sample heating products from electric-vaporization anti-mosquito mats, and the experimental results indicated that NTS effectiveness increased with decreasing adsorbent particle diameter. Substantially less mass of gaseous BTEX was extracted using 100-µm PDMS SPME fiber than with NTS of 100–120 mesh DVB for 60-min TWA sampling of anti-mosquito mats. The 100–120 mesh DVB-NTS primarily adsorbed 4.2 ng acetone, 13.3 ng dichloromethane, and 4.5–25.3 ng C10–C12 alkanes.Implications: The needle trap sampler (NTS) has been evaluated to be a device for sampling heating products from electric-vaporization anti-mosquito mats. Based on the experimental results, this investigation assessed NTS as suitable for occupational and environmental health applications.