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Solid Phase Microextraction Theory And Practice

Basics of Toxicology

A solid-phase microextraction (SPME) sampling device, called a needle trap samplers (NTS) that were packed with 60-80 mesh divinylbenzene (DVB) particles, was used to extract indoor volatile organic compounds (VOCs) that were emitted in an oil painting studio. This work compared the sampling performances of a passive NTS and an active charcoal desorption tube that was connected to a personal sampling pump (Method 1501), developed by the National Institute of Occupational Safety and Health, USA. The experimental results reveal that the NTS is a dependable alternative device to Method 1501 for monitoring indoor air quality. 2,2,4,6,6-Pentamethylheptane (isododecane) is the main emitted pollutant when oil painters use odorless thinner as a substitute solvent for turpentine oil, and the mean exposed concentrations of isododecane determined by NTS ranged from 0.83 to 3.10 ppm, which were dependent on whether the indoor ventilation was performed by the natural or mechanic mode. To maintain adequate air exchange rates in an oil painting studio, doors should be opened to increase air circulation, lowering the concentrations of isododecane to which painters are exposed.Implications: A needle trap sampler (NTS) was used to sample VOCs from oil painting in an indoor studio. Isododecane is the main emitted pollutant when painters use the odorless thinner. The NTS was evaluated to be a dependable alternative to Method 1501 for monitoring indoor air quality. To maintain adequate air exchange rates in a painting studio, doors should be opened to lower concentrations of VOCs.

https://www.tandfonline.com/doi/pdf/10.1080/10962247.2019.1694090

Use of passive SPME sampling devices to determine exposure of oil painters to organic compounds.

A quadrotor drone was equipped with an active solid phase microextraction (SPME) sampling device, known as a needle trap sampler (NTS), for extracting airborne volatile organic compounds (VOCs). The NTS, which has a 22-gauge stainless steel needle that is manually packed with 60–80-mesh adsorbent divinylbenzene (DVB) particles, was attached to a telescoping shaft to extend the sampling range beyond the strong downward stream that flows across the propellers of a hovering drone. The end of the NTS inlet was positioned below the head of the drone, which was the optimal location determined by using the flow simulation software SolidWorks. Our results confirm the feasibility of collecting toluene, ethylbenzene, and p-xylene matrix vapor with a telescoping SPME sampling device on a quadrotor drone using a pilot VOC exhaustion system. Therefore, we recommend this mobile system for sampling polluted air emitted by industrial factories.

/pdf/application-of-a-telescoping-microextraction-needle-trap-1i2sdtj9pr.pdf

Application of a telescoping microextraction needle trap sampling device on a drone to extract airborne organic vapors

Kaohsiung city located in the southern Taiwan is an industrial town and air pollutants were emitted from factories in the adjacent industrial zones. In order to track the pollution emission sources, a needle trap sampler (NTS), which is a micro solid phase microextraction (SPME) sampling device, was carried by a quadrotor drone to extract organic vapors from industries. The NTS was fabricated by packing divinylbenzene (DVB) particles of 60–80 mesh diameters into a 7 cm-long, 22-gauge stainless steel needle. The telescoping sampling device was carried by a DJI Mavic Pro quadrotor drone, and its effectiveness for extracting organic vapors from industrial processing air exhausts from chimneys was studied. The total weight of sampling device, including a NTS, a telescoping shaft, a Li-battery, a mini-air pump and the ABS (acrylonitrile butadiene styrene) loading frame, was less than 200 g. The mainly emitted compounds, including aromatic hydrocarbons (toluene of 1,450±650 ppb, ethylbenzene of 34±12 ppb and xylenes of 51±25 ppb), formaldehyde (50±12 ppb), alkanes (propane of 30±10 ppb), triacetin (7,620±1600 ppb) and terephthalic acid (20±5 ppb) were collected and then identified by the off-line gas chromatography (GC)-mass spectroscopy (MS) system in the laboratory. The quadrotor drone successfully monitored air pollution and tracked their emission sources from waste incineration, petroleum refinement, chemical processing and electronic part production.

/pdf/using-a-micro-sampler-on-a-drone-to-extract-organic-vapors-a-a2vja2l960.pdf

Using a Micro Sampler on a Drone to Extract Organic Vapors—A Case Study of Monitoring Industrial Pollution

Needle trap samplers (NTS), which are environmentally friendly solid phase microextraction sampling devices, were used to obtain air samples at a medical examination center in a teaching hospital to determine the concentration of airborne xylene. The standard active sampling method, Method 1501, was simultaneously used to evaluate the exposure of workers to xylene. The concentrations of xylene were much lower than the legal 100-ppm time-weighted average (TWA) concentration. Another organic reagent used in the medical examination center, formaldehyde, did not exhibit co-adsorption along with the extraction of xylene by NTS. The use of a fume hood satisfactorily reduced VOC emissions in the workplace. Additionally, a management strategy involving chemical control banding was adopted to evaluate the emission control of xylene and formaldehyde in this work. We recommend that workers wear the NTS as a routine micro-sampler in order to protect their health.

/pdf/assessing-organic-chemical-emissions-and-workers-risk-of-52hpchgj3a.pdf

Assessing Organic Chemical Emissions and Workers’ Risk of Exposure in a Medical Examination Center Using Solid Phase Microextraction Devices

Noise exposure can lead to various kinds of disorders. Noise-induced hearing loss (NIHL) is one of the leading disorders confusing the noise-exposed workers. It is essential to identify NIHL markers for its early diagnosis and new therapeutic targets for its treatment. In this study, a total of 90 plasma samples from 60 noise-exposed steel factory male workers (the noise group) with (NIHL group, n = 30) and without NIHL (non-NIHL group, n = 30) and 30 male controls without noise exposure (control group) were collected. Untargeted human plasma metabolomic profiles were determined with HPLC-MS/MS. The levels of the metabolites in the samples were normalized to total peak intensity, and the processed data were subjected to multivariate data analysis. The Wilcoxon test and orthogonal partial least square-discriminant analysis (OPLS-DA) were performed. With the threshold of p < 0.05 and the variable importance of projection (VIP) value >1, 469 differential plasma metabolites associated with noise exposure (DMs-NE) were identified, and their associated 58 KEGG pathways were indicated. In total, 33 differential metabolites associated with NIHL (DMs-NIHL) and their associated 12 KEGG pathways were identified. There were six common pathways associated with both noise exposure and NIHL. Through multiple comparisons, seven metabolites were shown to be dysregulated in the NIHL group compared with the other two groups. Through LASSO regression analysis, two risk models were constructed for NIHL status predication which could discriminate NIHL from non-NIHL workers with the area under the curve (AUC) values of 0.840 and 0.872, respectively, indicating their efficiency in NIHL diagnosis. To validate the results of the metabolomics, cochlear gene expression comparisons between susceptible and resistant mice in the GSE8342 dataset from Gene Expression Omnibus (GEO) were performed. The immune response and cell death-related processes were highlighted for their close relations with noise exposure, indicating their critical roles in noise-induced disorders. We concluded that there was a significant difference between the metabolite’s profiles between NIHL cases and non-NIHL individuals. Noise exposure could lead to dysregulations of a variety of biological pathways, especially immune response and cell death-related processes. Our results might provide new clues for noise exposure studies and NIHL diagnosis.

Plasma metabolomics analyses highlight the multifaceted effects of noise exposure and the diagnostic power of dysregulated metabolites for noise-induced hearing loss in steel workers

Hui-Min Wu

Papers

Assessing Organic Chemical Emissions and Workers’ Risk of Exposure in a Medical Examination Center Using Solid Phase Microextraction Devices

Plasma metabolomics analyses highlight the multifaceted effects of noise exposure and the diagnostic power of dysregulated metabolites for noise-induced hearing loss in steel workers