A novel quantitation method for phthalates in air using a combined thermal desorption/gas chromatography/mass spectrometry application

Atmospheric phthalate esters in a multi-function area of Hangzhou: Temporal variation, gas/particle phase distribution, and population exposure risk

Phthalate esters (PAEs) are prevalent in both indoor and outdoor environments. However, there are relatively few studies on phthalate contamination in the air of multi-function areas. Experiments were conducted to analyze the concentrations of 14 distinct PAEs in outdoor air in the college town of Hangzhou throughout both the warm and cold seasons. Correlation and principal component analyses were performed to investigate the influence and source factors of PAEs. This study also focused on the relationship between the gas/particle partition coefficient Kp and temperature, as well as the application of the gas/particle partition model. The risk of exposure to PAEs via inhalation was predicted for four groups of the general population: toddlers, adolescents, adults, and older adults. The results indicated that the concentration levels of Σ14PAEs in outdoor air were 1573 ng/m3 in the gaseous phase and 126 ng/m3 in the particulate phase. Additionally, this study indicated three primary sources of PAEs: indoor diffuse sources, industrial emission sources, and building construction sources. The gas/particle partitioning of PAEs also revealed that low-molecular-weight PAEs are more prevalent in gas, whereas high-molecular-weight PAEs are more predominant in the particle phase. A health risk analysis revealed high estimations of daily intakes (EDI) for toddlers and adolescents and high lifetime average daily doses (LADD) for older adults. This study establishes a solid foundation for formulating scientific and effective air pollution control measures by analyzing the characteristics and assessing the health risks of PAEs.

Analytical Method for Measurement of Tobacco-Specific Nitrosamines in E-Cigarette Liquid and Aerosol

An experimental method was developed and validated for the collection and analysis of tobacco-specific nitrosamines (TSNAs) that are present in electronic cigarette (EC) liquid or are released from aerosol samples using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system. As part of this study, the relative recovery of four target TSNAs was assessed by spiking standards in a mixture of propylene glycol and vegetable glycerin. Recovery was assessed against two major variables: (1) the chemical media (solution) selected for sample dilution (acetonitrile [ACN] vs. ammonium acetate [AA]) and (2) the type of sampling filter used (Cambridge filter pad [CFP] vs. quartz wool [QW] tube). The average recovery of TSNAs in terms of variable 1 was 134 ± 22.1% for ACN and 92.6 ± 8.27% for AA. The average recovery in terms of variable 2 was 83.4 ± 7.33% for QW and 58.5 ± 12.9% for CFP. Based on these conditions, the detection limits of N′-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N′-nitrosoanatabine (NAT), and N′-nitrosoanabasine (NAB) were calculated as 4.40, 4.47, 3.71, and 3.28 ng mL−1, respectively. The concentration of TSNAs in liquid and aerosol samples of six commercial EC solutions was measured as below the detection limit.

Quantitative Determination of Phthalate Esters from Air Samples Using a Solid-Phase Extraction-type Collection Device

In this study, a solid-phase extraction-type collection device, with styrene-divinylbenzene polymer particles (Sunpak-H) as the adsorbent, was used for the quantitative determination of phthalate esters in air samples. The collection and elution recoveries of eight volatile phthalate esters, i.e., dimethyl phthalate, diethyl phthalate, dipropyl phthalate, diisobutyl phthalate, dibutyl phthalate, butyl-benzyl phthalate, di(2-ethylhexyl) phthalate, and dioctyl phthalate, were quantitatively evaluated. All analytes were collected using the device up to a sampling volume of 10000 L at a sampling temperature of 35°C without breakthrough. During air collection, moisture was not trapped on the adsorbent. The collected analytes were completely eluted from the device by passing 3 mL of acetone. The eluted solvent was injected into a gas chromatography-mass spectrometry system after the eluted solvent was concentrated, if necessary. After washing the adsorbent using acetone, the device could be reused more than 50 times. The limit of quantification for the analytes was less than 1 ng L^-1 in air at a sampling volume of 600 L with solvent concentration. This device was successfully applied for the quantitative determination of phthalate esters in real air samples, including indoor and in-car air.

ZnSO4 rescued vimentin from collapse in DBP-exposed Sertoli cells by attenuating ER stress and apoptosis

Sertoli cells (SCs) provide physical and nutritional support for spermatogenesis. Dibutyl phthalate (DBP) is a plasticizer that has male reproductive toxicity. The collapse of vimentin in DBP-exposed SCs is thought to induce the sloughing of spermatocytes from seminiferous tubules. In this study, we explored methods to rescue vimentin from collapse in DBP-exposed SCs. DBP not only induced the hyperphosphorylation of vimentin but also triggered endoplasmic reticulum (ER) stress and apoptosis in SCs. Treatment with BAPTA-AM, an antagonist of Ca²⁺, significantly decreased the level of phosphorylated vimentin, while LY294002, an inhibitor of Akt1, did not. ER stress and apoptosis remained at high levels, and the distribution of vimentin was not improved. ZnSO₄ treatment did not decrease the level of phosphorylated vimentin. However, after treatment, ER stress and apoptosis were obviously inhibited, and the distribution of vimentin was reconverted. These results indicated that ZnSO₄ could alleviate the collapse of vimentin by attenuating ER stress and apoptosis. This study suggested that an appropriate zinc supply might be a choice to alleviate DBP-induced adverse reproductive effects.

Characterization and flux assessment of airborne phthalates released from polyvinyl chloride consumer goods

The concentrations and fluxes of airborne phthalates were measured from five types of polyvinyl chloride (PVC) consumer products (vinyl flooring, wallcovering, child's toy, yoga mat, and edge protector) using a small chamber (impinger) system. Airborne phthalates released from each of those PVC samples were collected using sorbent (Tenax TA) tubes at three temperature control intervals (0, 3, and 6 h) under varying temperature conditions (25, 40, and 90 °C). A total of 11 phthalate compounds were quantified in the five PVC products examined in this study. To facilitate the comparison of phthalate emissions among PVC samples, their flux values were defined for total phthalates by summing the average fluxes of all 11 phthalates generated during the control period of 6 h. The highest flux values were seen in the edge protector sample at all temperatures (0.40 (25 °C), 9.65 (40 °C), and 75.7 μg m^-2 h^-1 (90 °C)) of which emission was dominated by dibutyl isophthalate. In contrast, the lowest fluxes were found in wallcovering (0.01 (25 °C) and 0.05 μg m^-2 h^-1 (40 °C)) and child's toy (0.23 μg m^-2 h^-1 (90 °C)) at each temperature level. The information regarding phthalate composition and emission patterns varied dynamically with type of PVC sample, controlled temperature, and duration of control.

Critical evaluation of several techniques for the analysis of phthalates and terephthalates: Application to liquids used in electronic cigarettes

This study describes several original methods that were developed with the goal of measuring phthalates and terephthalates. These methods include gas chromatography/mass spectrometry (GC/MS), GC/MS/MS, liquid chromatography with UV detection (LC/UV), LC/MS, and LC/MS/MS. The study compares the advantages and disadvantages of these methods and their applicability to measuring phthalates and terephthalates in the liquids used in electronic cigarettes (e-liquids). The analytes evaluated include eight phthalates and two terephthalates. The phthalates were diethyl, dibutyl, benzyl butyl, diphenyl, bis(2-ethylhexyl), di-n-octyl, diisononyl and diisodecyl. The terephthalates were dimethyl and bis(2-ethylhexyl). Intentionally, no cleanup or concentration step were used in the methods. The methods used two chromatographic standards, dimethyl phthalate-3,4,5,6-d₄, and di-(2-ethylhexyl) phthalate-3,4,5,6-d₄. All techniques were validated for selectivity/specificity, precision, sensitivity (evaluation of LOD and LOQ), as well as for repeatability and matrix interference. The GC methods were not adequate for the analysis of diphenyl, diisononyl, and diisodecyl phthalates which were not volatile enough to be seen in the conditions used for the GC separation. Also, alcohols should not be used as solvents for the injection of the sample in the GC system to avoid transesterification in the hot injection port. The single quadrupole MS detection in GC offers sensitivities around 1 μg/mL in the e-liquid and was not sensitive enough for the analysis of trace phthalates and terephthalates. Compared to all evaluated methods, the MS/MS detection in GC offered the best sensitivity (below 10 ng/mL in the e-liquid). The LC is adequate for the separation of all the evaluated analytes. However, the UV detection in LC does not offer good sensitivity compared to all the other techniques. The MS detection in LC provides poor sensitivity for terephthalates, but better than the UV for the rest of the analytes. The MS/MS detection for LC offers slightly better sensitivity than the MS detection, but both LC/MS and LC/MS/MS were only able to measure levels above about 100 ng/mL of analytes in the e-liquid. A group of 39 e-liquids were analyzed by three of the evaluated procedures. Benzyl butyl phthalate, bis(2-ethylhexyl) terephthalate, and di-n-octyl phthalate were not detected in the e-liquids. Some of the other evaluated phthalates were present at trace levels in certain e-liquids while most e-liquids did not contain phthalates at detectable levels.

The combined effects of sampling parameters on the sorbent tube sampling of phthalates in air

The adsorption properties of various sorbent materials were investigated to assess the factors affecting biases in the sorbent tube (ST) sampling of airborne phthalates. The recovery of phthalates was assessed critically in relation to four key sampling parameters: (1) three types of sorbent materials (quartz wool (QW), glass wool (GW), and quartz wool plus Tenax TA (QWTN)), (2) the concentration level of phthalate standards, (3) purge flow rate, and (4) purge volume for analysis based on a 'sorbent tube-thermal desorption-gas chromatography-mass spectrometry (ST-TD-GC-MS)' system. Among these parameters, the type of ST was the most influential in determining the recovery of phthalates. For a given ST type, the recovery of phthalates tends to improve with increases in the concentration level of standards. In case of QW and QWTN tubes, the breakthrough of phthalates was not observed up to the maximum purge volume (100 L) tested in this work; however, in case of GW, the recovery decreased drastically to 60% even at a purge volume of 1 L for low molecular weight phthalates. The results of our study demonstrate that accurate analysis of airborne phthalates can be achieved through proper control of key sampling parameters, particularly the choice of sorbent material.