Portable dehumidifiers condensed water: A novel matrix for the screening of semi-volatile compounds in indoor air

Predicting concentrations of volatile and semi-volatile compounds in indoor areas through analysis of condensed water samples. A proof of concept

Atmospheres from indoor areas contain a range of volatile and semi-volatile compounds to which inhabitants are exposed through breathing. Despite different qualitative approaches have been proposed for the identification of compounds associated to the vapor phase of confined areas, active sampling remains as the preferred technique when quantitative data is required. Herein, we investigate the correlations existing between concentrations in air and water condensates obtained from indoor areas. To this end, samples of both matrices were simultaneously collected and analyzed by gas chromatography mass spectrometry. After validation of sample concentration approaches for a selection of compounds, the effect of different operational conditions, and environmental variables, in their concentrations in condensed water was assessed. Levels in this matrix were hardly affected by sampling time, air flow through the dehumidifier device, and the environmental temperature and humidity. Thus, air water distribution coefficients (Kaw) could be estimated for fourteen out of sixteen pre-selected compounds. These values permitted a semiquantitative evaluation of their concentrations existing in air from different areas. In case of semi-volatile compounds (i.e. phenol, benzothiazole, phthalates), with log Kaw below -4.8, analysis of 50 mL water samples permitted to achieve lower limits of quantification than active air sampling for 3 h at a flowrate of 1 m3 h-1.

Suspect and non-target screening of semi-volatile emerging contaminants in indoor dust from Danish kindergartens

Indoor dust is a sink of hundreds of organic chemicals, and humans may potentially be exposed to these via indoor activities. This study investigated potentially harmful semi-volatile organic contaminants in indoor dust from Danish kindergartens using suspect and non-target screening on gas chromatography (GC)-Orbitrap, supported by target analyses using GC-low resolution mass spectrometry (LRMS). A suspect list of 41 chemicals with one or more toxicological endpoints, i.e. endocrine disruption, carcinogenicity, neurotoxicity and allergenicity, known or suspected to be present in indoor dust, was established including phthalate and non-phthalate plasticizers, flame retardants, bisphenols, biocides, UV filters and other plastic additives. Of these, 29 contaminants were detected in the indoor dust samples, also including several compounds that had been banned or restricted for years. In addition, 22 chemicals were tentatively identified via non-target screening. Several chemicals have not previously been detected in Danish indoor dust. Most of the detected chemicals are known to be potentially harmful for human health while hazard assessment of the remaining compounds indicated limited risks to human. However, children were not specifically considered in this hazard assessment.

Comprehensive characterization of volatile and semi-volatile compounds in e-liquids for electronic cigarette using gas chromatography accurate mass spectrometry

The consumption of electronic cigarettes is a habit with an increasing prevalence, particularly among youths. Knowing the composition of e-liquids used in these devices represents the first step to understand the potential impact of e-smoking in the health of consumers. Herein, a non-target screening methodology was applied to the identification of volatile and semi-volatile compounds in a set of e-liquids from different suppliers, with different flavors, and containing different kinds of additives, such as nicotine or cannabidiol. To this end, samples were characterized by gas chromatography accurate mass spectrometry, using a time-of-flight mass analyzer. Combination of deconvoluted electronic ionization mass spectra with linear retention index values, obtained for two columns with different selectivity, permitted the identification of more than 250 chemicals with different confidence levels. Among them, respiratory pro-inflammatory compounds, acetals of propylene glycol and glycerin with aldehydes, nicotine-related and non-related alkaloids, and psychoactive cannabinoids were confirmed as concerning compounds in e-liquid samples. Concentration ratios between propylene glycol acetals and parent aldehydes varied in the range from 2% (ethyl vanillin) to more than 80% (case of benzaldehyde). The ratios between the concentrations of delta-9-tetrahydrocannabinol and cannabidiol in e-liquids stayed in the range from 0.02% to 0.3%.

Electromembrane extraction of nicotine in inhaled aerosols from tobacco cigarettes, electronic cigarettes, and heated tobacco products

Heated tobacco products and electronic cigarettes are considered as alternatives to traditional tobacco cigarettes. However, it is crucial to monitor and compare the nicotine concentration in inhaled aerosols from these tobacco products, owing to the addictive nature and adverse effects of nicotine on human health. This study aimed to provide an electromembrane extraction (EME) combined liquid chromatography method to extract and determine nicotine in different inhaled aerosols. EME showed high extraction efficiency, selectivity, and sample clean-up capability. Under the optimal parameters, the linear range for nicotine was 0.1-200 mg L-1 (r2 > 0.9998), and the limit of detection was 0.02 mg L-1. Good precision was obtained with the intra- and inter-day relative standard deviations of 2.2 % and 2.8 %, respectively. Repeatability was satisfactory (<7.7 %), and recoveries ranged from 81.0 % to 112.8 %. Finally, this method has been successfully used for the determination and comparison of nicotine in aerosols from these three tobacco products.

Analytical Determination of Allergenic Fragrances in Indoor Air

Among all the emerging contaminants, fragrances are gaining more relevance for their proven allergenic and, in some cases, endocrine-disrupting properties. To date, little information exists on their concentration in the air. This study aims to fill this gap by developing a method for the determination of semivolatile fragrances in the indoor gaseous phase with sampling protocols usually adopted for the collection of atmospheric particulate matter (sampling time 24 h, flow rate 10 L min−1) and instrumental analysis by gas chromatography coupled with mass spectrometry. The method was developed on 66 analytes and tested at three concentration levels: 20 compounds showed analytical recoveries ≥72% with percentage standard deviations always better than 20%. For most compounds, negligible sampling breakthroughs were observed. The method was then applied to real samples collected in a coffee bar and in a private house. Considering the fragrances for which the method has shown good effectiveness, the highest concentrations were observed for carvone in the coffee bar (349 ng m−3) and camphor in the house (157 ng m−3). As concerns certain or suspected endocrine disruptors, lilyal and galaxolide were detected at both sites, α-isomethylionone was the second most concentrated compound in the house (63.2 ng m−3), musk xylene and musk ketone were present at lower concentration (≈ 1 or 2 ng m−3).

Sustainability of Heating, Ventilation and Air-Conditioning (HVAC) Systems in Buildings-An Overview

Increasing demand on heating, ventilation, and air-conditioning (HVAC) systems and their importance, as the respiratory system of buildings, in developing and spreading various microbial contaminations and diseases with their huge global energy consumption share have forced researchers, industries, and policymakers to focus on improving the sustainability of HVAC systems. Understanding and considering various parameters related to the sustainability of new and existing HVAC systems as the respiratory system of buildings are vital to providing healthy, energy-efficient, and economical options for various building types. However, the greatest opportunities for improving the sustainability of HVAC systems exist at the design stage of new facilities and the retrofitting of existing equipment. Considering the high available percentage of existing HVAC systems globally reveals the importance of their retrofitting. The attempt has been made to gather all important parameters that affect decision-making to select the optimum HVAC system development considerations among the various opportunities that are available for sustainability improvement.

Assessment of direct analysis in real time accurate mass spectrometry for the determination of triclosan in complex matrices

In this work, the applicability of direct analysis in real time coupled to accurate mass spectrometry (DART-MS) to the quantitative determination of triclosan (TCS) in samples with increasing complexity, from personal care products to extracts from sewage, is investigated. In the first term, DART-MS spectra of TCS as free phenol and as derivatized species are characterized; thereafter, the effects of several instrumental variables in the detectability of TCS (i.e., temperature, solvent, and compound holder) are discussed. Under final selected conditions, TCS was determined from its [M-H]- ions, without need of derivatization, attaining an instrumental limit of quantification of 5 ng mL-1, with a linear response range up to 1000 ng mL-1. Complex matrices, such as solid-phase extracts obtained from environmental water samples, moderately inhibited the ionization efficiency of TCS, with signal attenuation percentages in the range of 6 to 57%, depending on the sample type and on the concentration factor provided by the SPE procedure. The accuracy of results obtained by DART-MS was evaluated using liquid chromatography (LC) with MS detection; in both cases, a time-of-flight (TOF) MS instrument was employed for the selective determination of the [M-H]- ions of TCS (m/z values 286.9439 and 288.9410) using a mass window of 20 ppm. DART-MS did not only provide enough sensitivity to detect the presence of TCS in environmental samples (raw and treated wastewater as well as freeze-dried sludge), but also measured concentrations matched those determined by LC-ESI-TOF-MS, with only slightly higher standard deviations. During analysis of personal care products, containing much higher concentrations of TCS in a less complex matrix, both techniques were equivalent in terms of accuracy and precision. Graphical abstract.

Recent trends in the chromatographic analysis of volatile flavor and fragrance compounds: Annual review 2020

The chromatographic analysis of volatile flavor and fragrance compounds is performed routinely in several industries and in many fields of scientific research. Typical applications include food-, environmental-, essential oil- and cosmetics analysis. Even though the analysis of flavors and fragrances have become increasingly standardized during the past decade, there are still a large variety of techniques that can be used for their extraction, chemical analysis, and sensory analysis. Moreover, there are certain less commonly used techniques that are now being used with increased frequency and that are showing the potential of being used as alternatives to the existing standard techniques. In this annual review, the techniques that were most commonly used in 2020 for the investigation of these volatile compounds are discussed. In addition, a number of emerging trends are discussed, notably the use of solvent assisted flavor evaporation (SAFE) for extraction, GC ion mobility spectrometry (IMS) for volatile compound analysis and electronic senses, that is, E-noses and E-tongues, for sensory analysis. Miscellaneous hyphenated techniques, advances in stationary phase chemistry and a number of interesting applications are also highlighted.

Portable dehumidifiers as an original matrix for the study of inhalable nanoparticles in school

Good air quality is documented as a significant factor of social justice. The human health hazards associated with air pollution are not distributed equally across cities; the most vulnerable people are more exposed to ambient air as they commute to work and wait for buses or trains at the stations. Aerosols play important roles in atmosphere quality and the climate; their oxidation at the nanoscale level may possibly increase the reactivity and toxicity of atmospheric particulates. Indoor school environments are characterized by high concentrations of different airborne particulate and gaseous pollutants. The documentation of nanoparticles (NPs), ultra-fine particles (UFPs), and micron-size particle species present in indoor primary schools are an important aspect in the recognition of their influence in respirational difficulties and decreased cognitive progress in children. This work utilizes the study of condensed water, sampled with portable dehumidifiers (PD), to describe NPs and UFPs in the vapor stage of enclosed zones. The acquired extracts were analyzed by advanced electron microscopy techniques. A total of 392 NPs and 251 UFPs were examined in a set of 22 samples acquired in moderately limited or inadequately ventilated indoor areas from several schools. Noting that NPs-related disorders happen at particular places of respirational structure, identification of site-specific NPs accumulation should be anticipated in direction to better verify the corresponding human health outcomes resulting from respirable NPs.