Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

Method development for thermal desorption-gas chromatography-tandem mass spectrometry (TD-GC-MS/MS) analysis of trace level fluorotelomer alcohols emitted from consumer products

The scientific foundation for per- and polyfluoroalkyl substances (PFAS) measurements in water, soils, sediments, biosolids, biota, and outdoor air has rapidly expanded; however, there are limited efforts devoted to developing analytical methods to measure vapor-phase PFAS in indoor air. A gas chromatography-tandem mass spectrometry (GC-MS/MS) method coupled with thermal desorption (TD) sorbent tube analysis was developed to quantify trace levels of fluorotelomer alcohols (FTOHs) emitted from consumer products in the indoor environment. Method evaluation included determination of instrument detection limits (IDLs), quality assurance checks of target standards purchased from different vendors, sample loss during storage, and TD sorbent breakthrough with tubes coupled in-series. The IDLs for TD-GC-MS/MS analyses ranged from 0.07 - 0.09 ng/tube. No significant loss of FTOHs was observed during stability tests over 28 days with relative standard deviations (RSDs) of spiked TD tubes ranging from 3.1 - 7.7% and the RSDs of polypropylene copolymer vial storage of standard solutions ranging from 4.3 - 8.4%. TD tube breakthrough was minimal with recovered FTOHs in the second tubes <1% of the spiked concentrations in the first tubes with carrier gas volume up to 20 L. The method has been applied to determine FTOH emissions from three consumer products in micro-scale chambers. A liquid stone cleaner/sealer product contained the highest levels of 6:2, 8:2, and 10:2 FTOHs, while the mattress pad products contained lower levels of 8:2 and 10:2 FTOHs. The emission parameters, including the initial emission factors and first order decay rate constants, were obtained based on the experimental data. The developed methods are sensitive and specific for analysis of all four target FTOHs (4:2, 6:2, 8:2, 10:2 FTOHs) with chamber testing. The methods can be extended to indoor air sampling and could be applicable to ambient air sampling.

Screening for 32 per- and polyfluoroalkyl substances (PFAS) including GenX in sludges from 43 WWTPs located in the Czech Republic - Evaluation of potential accumulation in vegetables after application of biosolids

Highly persistent, toxic and bioaccumulative per - and polyfluoroalkyl substances (PFAS) represents a serious problem for the environment and their concentrations and fate remain largely unknown. The present study consists of a PFAS screening in sludges originating from 43 wastewater treatment plants (WWTPs) in the Czech Republic. To analyze an extended group of PFAS consisting of 32 PFAS, including GenX and other new replacements of older and restricted PFAS in sludge, a new method was optimized and validated using pressurized solvent extraction, followed by the SPE clean-up step to eliminate the observed matrix effects and LC-MS/MS. The results revealed high PFAS contamination of sewage sludge, reaching values from 5.6 to 963.2 ng g^-1. The results showed that in the majority of the samples (about 60%), PFOS was the most abundant among the targeted PFAS, reaching 932.9 ng g^-1. Approximately 20% of the analyzed samples contained more short-chain PFAS, suggesting the replacement of long-chain PFAS (especially restricted PFOA and PFOS). GenX was detected in 9 samples, confirming the trend in the use of new PFAS. The results revealed that significantly higher contamination was detected in the samples from large WWTPs (population equivalent > 50,000; p-value <0.05). Concerning the application of sludge in agriculture, our prediction using the respective PFAS bioconcentration factors, the observed concentrations, and the legislatively permitted management of biosolids in Czech Republic agriculture revealed that PFAS can cause serious contamination of cereals and vegetables (oat, celery shoots and lettuce leaves), as well as general secondary contamination of the environment.

Substitution of PFAS chemistry in outdoor apparel and the impact on repellency performance

Intensifying legislation and increased research on the toxicological and persistent nature of per- and polyfluoroalkyl substances (PFASs) have recently influenced the direction of liquid repellent chemistry use; environmental, social, and sustainability responsibilities are at the crux. Without PFAS chemistry, it is challenging to meet current textile industry liquid repellency requirements, which is a highly desirable property, particularly in outdoor apparel where the technology helps to provide the wearer with essential protection from adverse environmental conditions. Herein, complexities between required functionality, legislation and sustainability within outdoor apparel are discussed, and fundamental technical performance of commercially available long-chain (C8) PFASs, shorter-chain (C6) PFASs, and non-fluorinated repellent chemistries finishes are evaluated comparatively. Non-fluorinated finishes provided no oil repellency, and were clearly inferior in this property to PFAS-finished fabrics that demonstrated good oil-resistance. However, water repellency ratings were similar across the range of all finished fabrics tested, all demonstrating a high level of resistance to wetting, and several non-fluorinated repellent fabrics provide similar water repellency to long-chain (C8) PFAS or shorter-chain (C6) PFAS finished fabrics. The primary repellency function required in outdoor apparel is water repellency, and we would propose that the use of PFAS chemistry for such garments is over-engineering, providing oil repellency that is in excess of user requirements. Accordingly, significant environmental and toxicological benefits could be achieved by switching outdoor apparel to non-fluorinated finishes without a significant reduction in garment water-repellency performance. These conclusions are being supported by further research into the effect of laundering, abrasion and ageing of these fabrics.

Determination of fluorotelomer alcohols in selected consumer products and preliminary investigation of their fate in the indoor environment

The U.S. Environmental Protection Agency (EPA) has established an ongoing effort to identify the major perfluorocarboxylic acid (PFCA) sources in nonoccupational indoor environments and characterize their transport and fate. This study determined the concentrations of fluorotelomer alcohols (FTOHs), which are the precursors to PFCAs, in fifty-four consumer products collected from the U.S. open market in the years of 2011 and 2013. The products included carpet, commercial carpet-care liquids, household carpet/fabric-care liquids, treated apparel, treated home textiles, treated non-woven medical garments, floor waxes, food-contact paper, membranes for apparel, and thread-sealant tapes. The FTOHs quantified were 1H,1H,2H,2H-perfluoro-1-octanol (6:2 FTOH), 1H,1H,2H,2H-perfluoro-1-decanol (8:2 FTOH), and 1H,1H,2H,2H-perfluoro-1-dodecanol (10:2 FTOH). The content of 6:2 FTOH ranged from non-delectable to 331μgg(-1), 8:2 FTOH from non-delectable to 92μgg(-1), and 10:2 FTOH from non-detectable to 24μgg(-1). In addition, two consumer products from the home textile category were tested in the washing-drying process. One product from the treated apparel category and one from the home textile category were tested in the micro-scale chamber under elevated temperatures. The experimental data show that the washing-drying process with one cycle did not significantly reduce the FTOH concentrations in the tested consumer products. FTOH off-gassing was observed under accelerated aging conditions. Future tests should include air sampling to allow determination of the absolute emission rates at different temperatures. The results of this study should be informative to exposure assessment and risk management.

Concentrations and trends of perfluorinated chemicals in potential indoor sources from 2007 through 2011 in the US

Certain perfluorinated chemicals (PFCs) in consumer products used indoors are potential indoor PFCs sources and have been associated with developmental toxicity and other adverse health effects in laboratory animals (Lao et al., 2007). The concentrations of selected PFCs including perfluorooctanoic acid (PFOA) and other perfluorocarboxylic acids (PFCAs), in 35 selected consumer products that are commonly used in indoors were measured from the year of 2007 through 2011. The products collected included carpet, commercial carpet-care liquids, household carpet/fabric-care liquids, treated apparel, treated home textiles, treated non-woven medical garments, floor waxes, food-contact paper, membranes for apparel, and thread-sealant tapes. They were purchased from retail outlets in the United States between March 2007 and September 2011. The perfluorocarboxylic acid (PFCA) contents in the products have shown an overall downward trend. However, PFOA (C8) could still be detected in many products that we analyzed. Reductions of PFCAs were shown in both short-chain PFCAs (sum of C4 to C7) and long-chain PFCAs (sum of C8 to C12) over the study period. There were no significant changes observed between short-chain PFCAs and long-chain PFCAs. Fourteen products were analyzed to determine the amounts of perfluoroalkyl sulfonates (PFASs) they contained. These limited data show the pronounced increase of perfluoro-butane sulfonate (PFBS), an alternative to perfluorooctanoic sulfonate (PFOS), in the samples. A longer and wider range of study will be required to confirm this observed trend.

Fate of polyfluoroalkyl phosphate diesters and their metabolites in biosolids-applied soil: biodegradation and plant uptake in greenhouse and field experiments

Significant contamination of perfluoroalkyl acids (PFAAs) in wastewater treatment plant (WWTP) sludge implicates the practice of applying treated sludge or biosolids as a potential source of these chemicals onto agricultural farmlands. Recent efforts to characterize the sources of PFAAs in the environment have unveiled a number of fluorotelomer-based materials that are capable of degrading to the perfluoroalkyl carboxylates (PFCAs), such as the polyfluoroalkyl phosphate diesters (diPAPs), which have been detected in WWTP and paper fiber biosolids. Here, a greenhouse microcosm was used to investigate the fate of endogenous diPAPs and PFCAs present in WWTP and paper fiber biosolids upon amendment of these materials with soil that had been sown with Medicago truncatula plants. Biodegradation pathways and plant uptake were further elucidated in a separate greenhouse microcosm supplemented with high concentrations of 6:2 diPAP. Biosolid-amended soil exhibited increased concentrations of diPAPs (4-83 ng/g dry weight (dw)) and PFCAs (0.1-19 ng/g dw), as compared to control soils (nd-1.4 ng/g dw). Both plant uptake and biotransformation contributed to the observed decline in diPAP soil concentrations over time. Biotransformation was further evidenced by the degradation of 6:2 diPAP to its corresponding fluorotelomer intermediates and C4-C7 PFCAs. Substantial plant accumulation of endogenous PFCAs present in the biosolids (0.1-138 ng/g wet weight (ww)) and those produced from 6:2 diPAP degradation (100-58 000 ng/g ww) were observed within 1.5 months of application, with the congener profile dominated by the short-chain PFCAs (C4-C6). This pattern was corroborated by the inverse relationship observed between the plant-soil accumulation factor (PSAF, Cplant/Csoil) and carbon chain length (p < 0.05, r = 0.90-0.97). These results were complemented by a field study in which the fate of diPAPs and PFCAs was investigated upon application of compost and paper fiber biosolids to two farm fields. Together, these studies provide the first evidence of soil biodegradation of diPAPs and the subsequent uptake of these chemicals and their metabolites into plants.

Fast determination of perfluorocompounds in packaging by focused ultrasound solid-liquid extraction and liquid chromatography coupled to quadrupole-time of flight mass spectrometry

A focused ultrasound solid-liquid extraction (FUSLE) and liquid chromatography (HPLC) coupled to quadrupole-time of flight mass spectrometry (QTOF-MS/MS) based method is proposed to determine six perfluorocarboxylic acids (PFCA) and perfluorooctane sulfonate (PFOS) in food-contact packaging. FUSLE, a simple, inexpensive and fast extraction technique, has been carried out with just 8mL of ethanol in one cycle of only 10s. The whole method presented good repeatability and intermediate precision, with RSDs below 11% and 15%, respectively; limits of detection, with values between 0.5ng/g and 2.2ng/g, and successful recovery values, around 100% in all cases. The developed method has been validated and applied to the analysis of real food-contact packaging samples. FUSLE results have been compared to those obtained with pressurized liquid extraction (PLE) and no significant differences between them have been found. PFAA were detected in all the packaging samples analyzed, in a concentration range between 4ng/g and 29ng/g, being PFHpA (perfluoroheptanoic acid) the most abundant of them.

Determination of perfluorocompounds in popcorn packaging by pressurised liquid extraction and ultra-performance liquid chromatography-tandem mass spectrometry

The development and characterisation of a method based on reverse-phase ultra-performance liquid chromatography (UPLC) coupled to a quadrupole-time of flight mass spectrometer (Q-TOF-MS) with negative electrospray ionisation (ESI) to determine perfluorinated compounds (PFCs) in packaging is presented in this paper. Analytes were quantitatively recovered from packaging with methanol in only one PLE cycle of 6 min at 100 °C. The UPLC allowed the successful separation of the studied PFCs in less than 4 min. The whole method presented good precision, with RSDs below 8%, LODs from 0.6 to 16 ng g(-1); and excellent recovery values, around 100% in all cases, were achieved. The PLE-UPLC-MS method was applied to the analysis of popcorn packaging for microwave cooking. Besides the most commonly studied PFCs: PFOA and PFOS, the presence of other perfluorocarboxylic acids (PFCAs) in popcorn packaging is evidenced in this work.