Determination of phthalate esters in polyvinyl chloride infusion bag by stir bar sorptive extraction combined with GC

PM2.5 bound phthalates in four metropolitan cities of China: Concentration, seasonal pattern and health risk via inhalation

Phthalates (PAEs) are in a group of artificial chemicals with potential adverse effects to human health and they can be frequently detected in environmental matrices due to its extensive usage. However, seasonal patterns of concentrations in atmosphere and risks posed by PAEs in airborne PM_2.5 to Chinese population have not been well characterized. During the period of November 2015 to March 2017, samples of fine particulate matter (PM_2.5) were collected in four cities of Guangzhou, Shanghai, Beijing and Harbin, which are major metropolitan areas of various latitudes of China. Concentrations of fourteen PAEs in airborne PM_2.5 were quantified using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Estimated daily intakes (EDIs), hazard quotients (HQs) and hazard index (HI) were calculated. Lifetime average daily doses (LADD) and incremental lifetime cancer risks (ILCR) of di(2-ethylhexyl) phthalate (DEHP) for four age groups, which divide with infant, toddler, adolescent and adult, by inhalation route were evaluated. Dimethyl phthalate (DMP), Diethyl phthalate (DEP), Di-n-butyl phthalate (DBP), and DEHP were the four major PAEs contaminants in these PM_2.5 samples. The sum concentrations of DMP, DEP, DBP and DEHP in Guangzhou, Shanghai, Beijing and Harbin ranged from 32.5-76.1, 10.1-101, 8.02-107 and 13.5-622 ng/m³, with mean concentrations of 59.1, 50.8, 43.8 and 136 ng/m³, respectively. The concentration of total PAEs in PM_2.5 from higher latitudes city (Harbin) was higher than those from lower latitudes cities (Guangzhou and Shanghai). Total concentrations of PAEs were significantly higher during warmer seasons than those during colder seasons among the four cities. Although the EDIs, HQs, and HI for all age groups were less than the threshold set by the U.S. Environmental Protection Agency (US EPA) and European Food Safety Authority (EFSA), the highest values of 70-years ILCR from Shanghai and Harbin were 1.2 × 10^-6 and 1.3 × 10^-6, which were slightly beyond the acceptable level of 10^-6. These findings reveal that the cancer risks of DEHP bound to PM_2.5 in these two cites should be of particular concern.

Electrospun polycaprolactam-manganese oxide fiber for headspace-solid phase microextraction of phthalate esters in water samples

The nanofibrous polycaprolactam (polyamide 6 (PA6)) incorporated with manganese oxide (MnO) nanoparticles was fabricated by electrospinning and used as a new fiber coating for headspace-solid phase microextraction (HS-SPME) of the selected phthalate esters (PEs) in water samples prior to GC-μECD. The adsorbent was fully characterized using scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The main parameters that affect the HS-SPME efficiency such as extraction temperature, ionic strength, extraction and desorption times were investigated. The analytical figures of merit were obtained under the optimized conditions as follows: linear dynamic range (LDR), 0.500-5.00 × 10² ng mL^-1; relative standard deviations (RSDs, n = 3), 1.86-10.9%; limits of detection (LODs), 0.0400-0.193 ng mL^-1. The method was applied for determination of the target analytes in river water, bottled water, mineral water and soda samples and the relative recoveries were obtained between 90.3 and 107%.

Bioaccumulation and bound-residue formation of 14C-decabromodiphenyl ether in an earthworm-soil system

Decabromodiphenyl ether (DecaBDE) is one of the most frequently detected flame retardants in terrestrial environments. However, the fate of DecaBDE and its transport in an earthworm-soil system with and without a DecaBDE-degrading strain have rarely been evaluated. In this study, ¹⁴C-DecaBDE was self-synthesized, and a DBDE-degrading strain, Rhodococcus erythropolis, was used in an earthworm-soil system. DecaBDE showed limited degradation and mineralization after 35days of all treatments. The bound-residue (BR) formation in soil was <2.5% in the system containing earthworms, which was significantly higher (p<0.05) than that observed in the absence of earthworms (<0.45%). DecaBDE could be adsorbed by the earthworms with a BSAF of ≤0.31. The distribution of ¹⁴C-DecaBDE concentrations in the earthworm roughly followed the pattern of crop gizzard>digestive system>head>tail>body wall, suggesting that DecaBDE was mainly uptaken through ingestion. Up to 31% of the ¹⁴C-DecaBDE in the earthworms was not extractable, revealing that the total concentration of accumulated ¹⁴C-DecaBDE was underestimated. The results also showed that the presence of DecaBDE-degrading bacteria did not significantly affect the fate of DecaBDE and its accumulation in earthworms. The study indicates that the conventional assessment of the bioaccumulation and ecological effects of DecaBDE, which is based only on extractable concentrations, may underestimate the risks.

Non-destructive plasticizer screening using a direct inlet probe-atmospheric pressure chemical ionization source and ion trap mass spectrometry

RATIONALE

In recent years, several ambient ionization techniques, where solid and/or liquid samples are brought directly into the ion source without any sample preparation and chromatographic separation, have been introduced for mass spectrometric (MS) analyses. Using the direct inlet probe-atmospheric pressure chemical ionization (DIP-APCI)-MS and DIP-APCI-MS(n) methods presented here, a non-destructive screening analysis for plasticizers directly from plastic articles can be performed.

METHODS

The DIP-APCI ion source developed in our laboratory uses a temperature-programmed push rod to introduce solid or liquid samples into a homemade APCI ion source. The DIP-APCI ion source was coupled to an ion trap (IT) mass spectrometer and selected source parameters were optimized. To enable a screening analysis for plasticizers, standards substances of several phthalates and other plasticizers were analyzed and their fragmentation behavior during collision-induced dissociation (CID) was studied.

RESULTS

Using DIP-APCI-ITMS, plasticizers can be detected directly from plastic articles and identification is possible through MS(n) experiments. For example, the isomeric phthalates di(2-ethylhexyl) phthalate and di-n-octyl phthalate can be differentiated according to their fragmentation behavior.

CONCLUSIONS

There are several advantages of the DIP-APCI source in comparison to many other ambient desorption ion sources: (i) well-defined gas phase matrix, (ii) precisely adjustable reagent gases (e.g. O2 for negative APCI), (iii) well-defined probe temperature, and (iv) fully automated operation.