Simultaneous determination of urinary 31 metabolites of VOCs, 8-hydroxy-2'-deoxyguanosine, and trans-3'-hydroxycotinine by UPLC-MS/MS: 13C- and 15N-labeled isotoped internal standards are more effective on reduction of matrix effect.

Human beings are inevitably exposed to volatile organic compounds (VOCs) of anthropogenic emissions as they are ubiquitous atmospheric pollutants. Smoking is an important exposure route of VOCs for the general population. Health effects induced by VOC exposure raise more concerns as they are identified with carcinogenicity, genotoxicity, neurotoxicity, and reproductive toxicity. trans-3'-Hydroxycotinine (OH-Cot) is a urinary biomarker of smoking, and 8-hydroxy-2'-deoxyguanosine (8-OHDG) is a urinary biomarker of DNA oxidative damage. To develop a method for quantifying VOC exposure levels of the general population and assessing the health risks induced by VOCs from second-hand smoking, an effective, rapid, and high-throughput method for the simultaneous determination of 31 metabolites of VOCs, 8-OHDG, and OH-Cot using solid-phase extraction coupled with UPLC-MS/MS was developed and validated. Method precision and accuracy, extraction recoveries, matrix effects, and storage stabilities of most analytes met the criterion (80-120%). Extraction recoveries increased from 85.1 to 100% after adjustment by isotoped internal standards (ISs). Furthermore, 13C- and 15N-labeled ISs were more effective to reduce the influence of matrix effects on recoveries and precisions than the deuterated analogs (73.0-116% vs. 53.6-140%). This developed method was successfully applied to determine urine samples collected from children. Results showed that N-acetyl-S-(3,4-dihydrobutyl)-L-cysteine, 2,2'-thiodiacetic acid (TGA), and N-acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine (HPMMA) were well correlated with 8-OHDG with coefficients higher than 0.82, indicating those VOCs might easily lead to DNA damage. In conclusion, our co-monitoring of metabolites of VOCs with 8-OHDG and OH-Cot in one method provides a robust analytical method, which not only suggests the potential adverse health effects induced by VOCs but also discriminates and evaluates the contribution of passive smoking in human VOC exposure. Graphical abstract.

Probabilistic risk assessment of occupational exposure to volatile organic compounds in the rendering plant of a poultry slaughterhouse.

In this study, occupational exposure to volatile organic compounds (VOCs) in the rendering plant of poultry slaughterhouse was determined and subsequently, carcinogen and non-carcinogenic risks were assessed using the US Environmental Protection Agency (USEPA). National Institute for Occupational Safety and Health (NIOSH) methods of 1501 and 1600 were used to measure VOCs in the breathing zone of the workers. Samples were analyzed by GC/MS. Carcinogenic and non-carcinogenic risks and sensitivity analysis were carried out using Monte Carlo simulations technique. The concentration of benzene and CS2 was higher than the occupational exposure limits (OEL). The hazard quotient (HQ) values for all measured compounds was more than 1, which indicating the high potential for non-carcinogenic risks. Furthermore, the calculated Lifetime Cancer Risks (LCR) for carcinogenic compounds revealed that cancer risk due to benzene is higher than the maximum acceptable level provided by USEPA (10-6). Based on the sensitivity analysis, the concentration and exposure frequency are the most important variable influencing both carcinogen and non-carcinogenic risks. Therefore, the concentration levels of the VOCs and exposure frequency should be controlled using engineering control measures.

A Novel Method for Soil Organic Matter Determination by Using an Artificial Olfactory System.

Soil organic matter (SOM) is a major indicator of soil fertility and nutrients. In this study, a soil organic matter measuring method based on an artificial olfactory system (AOS) was designed. An array composed of 10 identical gas sensors controlled at different temperatures was used to collect soil gases. From the response curve of each sensor, four features were extracted (maximum value, mean differential coefficient value, response area value, and the transient value at the 20th second). Then, soil organic matter regression prediction models were built based on back-propagation neural network (BPNN), support vector regression (SVR), and partial least squares regression (PLSR). The prediction performance of each model was evaluated using the coefficient of determination (R2), root-mean-square error (RMSE), and the ratio of performance to deviation (RPD). It was found that the R2 values between prediction (from BPNN, SVR, and PLSR) and observation were 0.880, 0.895, and 0.808. RMSEs were 14.916, 14.094, and 18.890, and RPDs were 2.837, 3.003, and 2.240, respectively. SVR had higher prediction ability than BPNN and PLSR and can be used to accurately predict organic matter contents. Thus, our findings offer brand new methods for predicting SOM.

Application of a novel reference material in an international round robin test on material emissions testing.

Emission testing of products is currently a rapidly increasing field of measurement activity. Labeling procedures for construction products are based on such emission test chamber measurements, and hence, measurement performance should be verified. One possible route is to conduct testing of one material in different laboratories within a round robin test (RRT), ideally using homogeneous reference materials, which can be used within interlaboratory studies or as part of the quality management system to ensure comparable results. The applicability of a lacquer system with nine added VOCs (hexanal, styrene, n-decane, limonene, 2-ethyl-1-hexanol, N-methyl-α-pyrrolidone, 2-ethylhexyl acrylate, dimethyl phthalate, and n-hexadecane) was evaluated in an international RRT with 55 participating laboratories. An intralaboratory quality check confirmed the homogeneity and reproducibility of the lacquer material for most of the compounds (RSD 5%-6%), which was confirmed in the RRT. However, emissions varied for the polar compound N-methyl-α-pyrrolidone and the higher boiling compounds 1,2-dimethyl phthalate, and n-hexadecane which could be traced back to analytical issues. In the RRT, the interlaboratory relative standard deviations (RSDs) ranged from 30% to 65% for all participants but for reference laboratories the range was between 20% and 45%.

Development of a Cigarette Tobacco Filler Standard Reference Material.

A new tobacco filler Standard Reference Material (SRM) has been issued by the National Institute of Standards and Technology (NIST) in September 2016 with certified and reference mass fraction values for nicotine, N-nitrosonornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and volatiles. The constituents have been determined by multiple analytical methods with measurements at NIST and at the Centers for Disease Control and Prevention, and with confirmatory measurements by commercial laboratories. This effort highlights the development of the first SRM for reduced nicotine and reduced tobacco-specific nitrosamines with certified values for composition.

Certified reference material of volatile organic compounds for environmental analysis: BTEX in methanol.

The Brazilian Metrology Institute (National Institute of Metrology, Quality, and Technology, Inmetro) has been developing a certified reference material (CRM) of the volatile organic compounds benzene; toluene; ethylbenzene; and ortho, meta, and para-xylenes (BTEX) in methanol, to ensure quality control for environmental-analysis measurements. The objective of this paper is to present the results of certification studies: uncertainty estimates related to characterization, a homogeneity study, and a stability study on a single lot of CRM composed of BTEX in methanol. The method used analysis of variance (ANOVA), a statistical tool, to evaluate the homogeneity and stability of the BTEX CRM, which complies with ISO Guide 30 series. The homogeneity and stability of the BTEX CRM was confirmed for all analytes and their respective properties. All the procedures used in this study complied with ISO GUIDE 34, ISO GUIDE 35, and the guide to the expression of uncertainty of measurement (GUM).

Development of a multi-VOC reference material for quality assurance in materials emission testing.

Emission test chamber measurement is necessary to proof building materials as sources of volatile organic compounds (VOCs). The results of such measurements are used to evaluate materials and label them according to their potential to emit harmful substances, polluting indoor air. If only labelled materials were installed indoors, this would improve indoor air quality and prevent negative impacts on human health. Because of the complex testing procedure, reference materials for the quality assurance are mandatory. Currently, there is a lack of such materials because most building products show a broad variation of emissions even within one batch. A previous study indicates lacquers, mixed with volatile organic pollutants, as reproducible emission source for a wide range of substances. In the present study, the curing of the lacquer-VOC mixture inside micro-chambers was optimised. Therefore, the humidity and the chamber flow were varied. Typical indoor air pollutants with a wide range of volatilities, for example, styrene, n-hexadecane, dimethyl and dibutyl phthalate were selected. It turned out that, under optimised curing parameters inside the micro-chamber, their emission can be reproduced with variations of less than 10 %. With this, a next important step towards a reference material for emission testing was achieved.

Evaluating a county-based healthy nail salon recognition program.

OBJECTIVES: The City of San Francisco, California established a recognition program for nail salons that use safer nail products and receive worker safety training. This pilot study examined whether participating salons had reduced levels of toluene, methyl methacrylate (MMA), and total volatile organic compounds (TVOC), and improved knowledge and behavior compared to control salons. METHODS: We conducted personal air monitoring and administered surveys assessing knowledge and behaviors of two workers from each of six intervention salons and five control salons. We conducted assessments before and after the worker training. RESULTS: Although non-significant, there was a reduction in toluene (-46% vs. 0%) and TVOC (-19% vs. +47%), but an increase in MMA (+113% and +72%) among intervention salons compared to control salons. Awareness of dibutyl phthalates in nail products increased (+55%) among intervention salons between surveys. CONCLUSIONS: A government-administered nail salon recognition program may reduce chemical exposures and increase work-related knowledge.

Influence of a portable air treatment unit on health-related quality indicators of indoor air in a classroom.

During periods of two weeks in February and June 2010 the performance of portable air treatment units (PATUs) was evaluated in a primary school classroom using indicators of indoor air quality. Air samples were collected in an undisturbed setting on weekend days and in an occupied setting during teaching hours. In the first week PATUs were turned off and in the second week they were turned on. On weekend days PATUs reduced indoor levels of PM-10 by 87% in February and by 70% in June compared to weekend days when PATUs were turned off. On schooldays, indoor PM-10 was increased by 6% in February and reduced by 42% in June. For PM-2.5 reductions on weekend days were 89% in February and 80% in June. On school days PM-2.5 was increased by 15% in February and reduced by 83% in June. Turning on the PATUs reduced total VOC by 80% on weekend days and by 57% on school days (but not in June). No influence on formaldehyde, NO(2), O(3) and molds was observed. PATUs appeared to be less effective in removal of air pollutants when used in an occupied classroom compared to an unoccupied setting. Our study suggests that such devices should be tested in real-life settings to evaluate their influence on indoor air quality.

Assessing the impact of the duration and intensity of inhalation exposure on the magnitude of the variability of internal dose metrics in children and adults.

The objective of this study was to assess the impact of the exposure duration and intensity on the human kinetic adjustment factor (HKAF). A physiologically based pharmacokinetic model was used to compute target dose metrics (i.e. maximum blood concentration (C(max)) and amount metabolized/L liver/24 h (Amet)) in adults, neonates (0-30 days), toddlers (1-3 years), and pregnant women following inhalation exposure to benzene, styrene, 1,1,1-trichloroethane and 1,4-dioxane. Exposure scenarios simulated involved various concentrations based on the chemical's reference concentration (low) and six of U.S. EPA's Acute Exposure Guideline Levels (AEGLs) (high), for durations of 10 min, 60 min, 8 h, and 24 h, as well as at steady-state. Distributions for body weight (BW), height (H), and hepatic CYP2E1 content were obtained from the literature or from P3M software, whereas blood flows and tissue volumes were calculated from BW and H. The HKAF was computed based on distributions of dose metrics obtained by Monte Carlo simulations [95th percentile in each subpopulation/median in adults]. At low levels of exposure, ranges of C(max)-based HKAF were 1-6.8 depending on the chemical, with 1,4-dioxane exhibiting the greatest values. At high levels of exposure, this range was 1.1-5.2, with styrene exhibiting the greatest value. Neonates were always the most sensitive subpopulation based on C(max), and pregnant women were most sensitive based on Amet in the majority of the cases (1.3-2.1). These results have shown that the chemical-specific HKAF varies as a function of exposure duration and intensity of inhalation exposures, and sometimes exceeds the default value used in risk assessments.

Use of reference chemicals to determine passive uptake rates of common indoor air VOCs by collocation deployment of active and passive samplers.

Passive samplers have become more popular in their application in the measurement of airborne chemicals. For volatile organic compounds, the rate of a chemical's diffusivity is a determining factor in the quantity of the chemical being collected for a given passive sampler. While uptake rate of a chemical in the passive sampler can be determined either by collocation deployment of both active and passive samplers or use of controlled facilities such as environmental chambers, a new approach without a need for accurate active flow rate in the collocation experiment was demonstrated in this study. This approach uses chemicals of known uptake rates as references to calculate the actual flow rate of the active sampling in the collocation experiment. The active sampling rate in turn can be used in the determination of the uptake rates of all other chemicals present in the passive samplers. The advantage of such approach is the elimination of the errors in actual active sampling rate associated with low flow employed in the collocation experiment. Using this approach, passive uptake rates of more than 80 volatile organic compounds commonly present in indoor air were determined. These experimentally determined uptake rates correlate well with air diffusivity of the chemicals, indicating the regression equation describing such correlation might be useful in predicting the uptake rates of other volatile organic chemicals in indoor air based on their air diffusivity.

Chemical-specific screening criteria for interpretation of biomonitoring data for volatile organic compounds (VOCs)--application of steady-state PBPK model solutions.

The National Health and Nutrition Examination Survey (NHANES) generates population-representative biomonitoring data for many chemicals including volatile organic compounds (VOCs) in blood. However, no health or risk-based screening values are available to evaluate these data from a health safety perspective or to use in prioritizing among chemicals for possible risk management actions. We gathered existing risk assessment-based chronic exposure reference values such as reference doses (RfDs), reference concentrations (RfCs), tolerable daily intakes (TDIs), cancer slope factors, etc. and key pharmacokinetic model parameters for 47 VOCs. Using steady-state solutions to a generic physiologically-based pharmacokinetic (PBPK) model structure, we estimated chemical-specific steady-state venous blood concentrations across chemicals associated with unit oral and inhalation exposure rates and with chronic exposure at the identified exposure reference values. The geometric means of the slopes relating modeled steady-state blood concentrations to steady-state exposure to a unit oral dose or unit inhalation concentration among 38 compounds with available pharmacokinetic parameters were 12.0 microg/L per mg/kg-d (geometric standard deviation [GSD] of 3.2) and 3.2 microg/L per mg/m(3) (GSD=1.7), respectively. Chemical-specific blood concentration screening values based on non-cancer reference values for both oral and inhalation exposure range from 0.0005 to 100 microg/L; blood concentrations associated with cancer risk-specific doses at the 1E-05 risk level ranged from 5E-06 to 6E-02 microg/L. The distribution of modeled steady-state blood concentrations associated with unit exposure levels across VOCs may provide a basis for estimating blood concentration screening values for VOCs that lack chemical-specific pharmacokinetic data. The screening blood concentrations presented here provide a tool for risk assessment-based evaluation of population biomonitoring data for VOCs and are most appropriately applied to central tendency estimates for such datasets.

Risk mitigation for indoor air quality using the example of construction products - efforts towards a harmonization of the health-related evaluation in the EU.

In Europe, the Construction Products Regulation sets harmonized conditions for the marketing of construction products with the objective of protecting the building users' health. Until now only three European countries have implemented requirements for the assessment of VOC emissions from construction products. Therefore, the European Commission is planning the issue of a delegated act on the communication of VOC emissions from construction products in the form of VOC classes. A key prerequisite for defining the VOC classes is the completion of the EU-LCI list currently being carried out by a group of experts from ten European countries. This paper reports on the development of the VOC class concept, the progress of the EU-LCI harmonization framework and Germany's current efforts to ensure a high level of health protection for building users and avoid dangers from construction product emissions.

Homogeneity assessment of reference materials for sensory analysis of liquid foodstuffs. The virgin olive oil as case study.

Sensory properties are critical characteristics that determine quality and can be evaluated by trained tasting panels. The panels function as multi-sensor measuring instrument and need the use of reference materials (RMs) for training. The homogeneity between units packaged from a batch of RM can be evaluated by gas chromatography coupled to flame ionization detection (GC-FID), using this instrumental technique as an alternative to sensory analysis. For this purpose, the fingerprint methodology is applied, taking into account that the homogeneity assessment will be based on evaluating the similarity between the fingerprints of the fraction of volatile organic compounds acquired from samples representative of the batch. The proposed methodology is applied with good results to evaluate the homogeneity of several RMs for sensory analysis of virgin olive oil samples, using similarity indices, control charts and exploratory analysis of multivariate data to observe the grouping RM and fingerprint regions representative of each defect.

Occupational risk resulting from exposure to mineral wool when installing insulation in buildings.

Mineral wool is widely used for thermal and sound insulation. The subject of the study is to identify hazards for employees resulting from exposure to mineral wool, when it is used to insulate buildings, and to assess the risk arising from this exposure. When installing mineral wool insulation, respirable mineral fibers, dust, and volatile organic compounds may pose a hazard at workplaces. Based on the results of concentration measurements, it was assessed that the probability of adverse health effects related to the work of insulation installers, resulting from exposure to mineral wool fibers, is low, but for dust associated with exposure, an average health risk was estimated. An additional threat may be the sensitizing effect of substances used as binders and additives improving the utility properties of mineral wool, for example, phenol formaldehyde resins. The paper also contains some information on the labeling of mineral wool; this is very important because the label allows downstream users to recognize mineral wools, the composition and properties of which cause that they are not classified as carcinogens. Int J Occup Med Environ Health. 2020;33(6):757-69.

A new system of refillable and uniquely identifiable diffusion tubes for dynamically generating VOC and SVOC standard atmospheres at ppm and ppb concentrations for calibration of field and laboratory measurements.

Calibration of trace analyses for volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) is an important but sometimes neglected aspect of environmental monitoring. Static methods using mixtures of VOCs in compressed air or nitrogen suffer from uncertain adsorptive losses on the gas cylinder wall and are not well suited for SVOCs. Dynamic methods enable generation of standards when needed, using permeation or diffusion tubes in thermostatted ovens through which a carrier gas flows whose flow-rate is user-controlled. We describe a new system of refillable diffusion tubes engraved with individual serial numbers (for quality systems traceability) that users can easily calibrate gravimetrically in a few weeks, compared with several months for gravimetric calibration of permeation tubes. These devices may be useful for calibrating ppm and ppb measurements of VOCs and SVOCs. Using appropriately low temperatures and an inert carrier gas, it may also be possible to generate standards for many labile and oxygen sensitive compounds.

Assessment of compliance level of ICH guidelines for organic volatile impurities in common ayurvedic hepatic formulations.

Background Herbal medicines have been used in the treatment of liver diseases for a long time. In recent years, the use of herbal medicines for protection from other strong antibiotics as well as drugs that can damage the liver during their metabolism in liver and for treatment of liver diseases has increased all over the world. It is important to mention that a number of organic solvents are used at different stages of extraction/formulation development for these traditional preparations in industries/pharmacies. In addition, some of these solvents possess established carcinogenic properties and may enter the formulation as residual solvents. Hence as per ICH guidelines it is mandatory to keep the level of these solvents up to permissible limits. There has been a lot of hue and cry that ayurvedic formulations available in the market are not properly standardized for their quality due to lack of stringent regulations and standards from regulatory authorities. Therefore the aim of present work was to assess the compliance of ICH guidelines for level of organic volatile impurities in common marketed ayurvedic hepatic formulations. Methods In this study, 25 ayurvedic herbal formulations available as OTC product have been assessed for presence of residual solvents using gas chromatography with flame ionization detector. Results This study on 25 fast moving hepatic formulations in the market reflects that no residual solvents were detected in any of the formulations however if present were within prescribed permissible limits of ICH guidelines. The data was also subjected to statistical analysis (F-test and t-test at 95% confidence level). Conclusions Results indicate the safety of these hepatic formulations with respect to residual solvents. In addition presents a simple, linear, specific, accurate, precise and rugged gas chromatographic method for estimation of residual solvents.

Comparison of two common adsorption materials for thermal desorption gas chromatography - mass spectrometry of biogenic volatile organic compounds.

Volatile organic compounds (VOCs) are commonly collected from gaseous samples by adsorption to materials such as the porous polymer Tenax TA. Adsorbed compounds are subsequently released from these materials by thermal desorption (TD) and separated then by gas chromatography (GC) with flame ionization (FID) or mass spectrometry (MS) detection. Tenax TA is known to be particularly suitable for non-polar to semipolar volatiles, however, many volatiles from environmental and biological samples possess a rather polar character. Therefore, we tested if the polymer XAD-2, which so far is widely used to adsorb organic compounds from aqueous and organic solvents, could provide a broader coverage for (semi)polar VOCs during gas-phase sampling. Mixtures of volatile compounds covering a wide range of volatility (bp. 20-256°C) and different chemical classes were introduced by liquid spiking into sorbent tubes with one of the two porous polymers, Tenax TA or XAD-2, and analyzed by TD/GC-MS. At first, an internal standard mixture composed of 17 authentic standards was used to optimize desorption temperature with respect to sorbent degradation and loading time for calibration. Secondly, we tested the detectability of a complex standard mixture composed of 57 volatiles, most of them common constituents of the body odor of mammals. Moreover, the performance of XAD-2 compared with Tenax TA was assessed as limit of quantitation and linearity for the internal standard mixture and 33 compounds from the complex standard mixture. Volatiles were analyzed in a range between 0.01-∼250ng/tube depending on the compound and material. Lower limits of quantitation were between 0.01 and 3 ng±<25% RSD (R2>0.9). Interestingly, we found different kinetics for compound adsorption with XAD-2, and a partially better sensitivity in comparison with Tenax TA. For these analytes, XAD-2 might be recommended as an alternative of Tenax TA for TD/GC-MS analysis.

Techniques and issues in breath and clinical sample headspace analysis for disease diagnosis.

Analysis of volatile organic compounds (VOCs) from breath or clinical samples for disease diagnosis is an attractive proposition because it is noninvasive and rapid. There are numerous studies showing its potential, yet there are barriers to its development. Sampling and sample handling is difficult, and when coupled with a variety of analytical instrumentation, the same samples can give different results. Background air and the environment a person has been exposed to can greatly affect the VOCs emitted by the body; however, this is not an easy problem to solve. This review investigates the use of VOCs in disease diagnosis, the analytical techniques employed and the problems associated with sample handling and standardization. It then suggests the barriers to future development.