[Simultaneous determination of 11 volatile perfluorinated compound precursors in textiles using gas chromatography-triple quadrupole mass spectrometry].

Perfluorinated compounds (PFCs) are persistent organic compounds. PFCs are artificially prepared hydrocarbons in which hydrogen atoms are completely replaced by fluorine. PFCs have excellent thermal stability and chemical stability, high surface activity, and hydrophobic and/or oleophobic properties owing to their exceptionally strong C-F bonds, low polarizability, and weak intermolecular van der Waals interactions. Currently, PFCs and their precursors are widely used in textile production as finishing agents and surfactants. In recent years, increasing attention has been devoted to PFCs and their precursors. In many countries and regions, such as the European Union, Canada, Denmark, and the United States, directives and regulations have been issued to restrict the use of PFCs and their precursors; the number of these compounds in such lists is increasing continuously. Studies have shown that PFCs are hepatotoxic, embryotoxic, reproductive-toxic, neurotoxic, and carcinogenic, and can interfere with the endocrine system, change animal instinct behavior, and potentially induce developmental neurotoxicity in humans, especially in young children. However, there are few established methods for the simultaneous detection of multiple PFC precursors, necessitating the same particularly for textiles. In this study, a method was developed for the simultaneous determination of 11 volatile PFC precursors in textiles using gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). The target compounds included four fluorotelomer alcohols (FTOHs), three fluorotelomer acrylates (FTAs), two fluorooctane sulfonamides (FOSAs), and two fluorooctane sulfonamide-ethanols (FOSEs). Studies have shown that FTOHs and FTAs are precursors of perfluorocarboxylic acid, and FOSAs are precursors of perfluorooctanesulfonic acid. Some PFC precursors are converted into perfluorocarboxylic acid and perfluoroalkyl sulfonic acid, which threaten human health and ecological security. In this study, an effective ultrasonic-assisted extraction method for the 11 target compounds was established. The effects of the extraction solvent, extraction temperature, and extraction time on the extraction efficiency were investigated. The optimum extraction conditions for the developed method were carrying out ultrasonic extraction at 70 ℃ for 60 min with methanol as the extraction solvent. Separation was performed on a VF-WAXms capillary column (30 m×0.25 mm×0.25 µm) with temperature programming, following which the target compounds were detected by GC-MS/MS in the multiple reaction monitoring (MRM) mode and quantified using the external standard method. The matrix effects of three textile matrices were also investigated. The calibration curves of the 11 volatile PFC precursors showed good linearity in the concentration range of 10-500 µg/L with correlation coefficients not less than 0.9984. The limits of detection were 0.002-0.04 mg/kg (S/N=3), and limits of quantification were 0.006-0.1 mg/kg (S/N=10). The recoveries for the 11 analytes in different textile matrix samples at three spiked levels ranged from 73.2% to 117.2% with relative standard deviations (RSDs) of 0.1%-9.4% (n=6). Through actual sample analysis, four PFC precursors were detected in the textile product samples. The method has the advantages of simple pretreatment, accurate qualitative and quantitative analysis, high sensitivity, and good reproducibility. It can be effectively used for the simultaneous determination of 11 volatile PFC precursors in textiles. The establishment of this method has theoretical and practical significance for controlling PFC precursor levels in textiles. This study offers a new testing method for mitigating risk to safety and controlling textile products. It also provides a reference for establishing testing standards for PFC precursors in textiles and other similar consumer goods.

Enhanced photocatalysis using metal-organic framework MIL-101(Fe) for organophosphate degradation in water.

Metal-organic frameworks (MOFs) are attractive novel classes of porous materials with diverse potentiality and easily tailored structures. It is desirable to evaluate the performance of MOFs as photocatalysts for organic contaminant removal in aqueous matrixes. In this study, iron-based MIL-101(Fe) was synthesized and a photo-Fenton reaction system (multiple wavelength light + MIL-101(Fe) + H2O2) was developed for elimination of tris(2-chloroethyl) phosphate (TCEP). Degradation pattern of TCEP followed an S-shape curve, which included a slow induction period and a rapid radical oxidation process. Transport of reactants into MIL-101(Fe) and the activation of electron transport within Fe-O clusters of MIL-101(Fe) may be the dominant mechanisms in the induction period, while a pseudo-first-order kinetics was observed in the hydroxyl radical oxidation process. Removal efficiencies in these two stages highly depended on the reaction conditions. Irradiation at 420 nm and acid condition were conductive, while high temperature and high [H2O2]:[MIL-101(Fe)] mass ratio accelerated the reaction. Before complete mineralization, eleven degradation products were generated, and the dominant degradation pathways included cleavage, hydroxylation, carbonylation, and carboxylation. Under acid condition (pH = 3), only 1% mass loss was observed after 60-min reaction, but the iron leakage was aggravated when pH increased. Furthermore, this MOF-photo-Fenton system demonstrated a robust performance on TCEP degradation in actual wastewater matrixes under acid condition. Generally, the MOF-photo-Fenton system is a potential technology for elimination of organic pollutants in aqueous solution.

Determination of ADH in textiles using the HPLC-MS/MS method and the study of its adsorption behaviour towards formaldehyde.

In the textile industry, formaldehyde-based resins are used as finishers to make the fabrics crease-resistant, which are the main source of formaldehyde in textiles. In our practical study, there are cases that prove that textile products containing adipic dihydrazide (ADH) will continuously adsorb formaldehyde from the surrounding environment during storage. In this study, a high performance liquid chromatography-tandem mass spectrometry method was established for the precise determination of ADH in textiles. The method was optimized in terms of instrument conditions, extraction temperature, extraction time, and extraction mode. Under optimum test conditions, ADH was determined precisely with the linearity range of 0.05-2 mg L-1 and correlation coefficient (R 2) of 0.9993. Recovery rate and repeatability were tested; the data showed that the recovery rate of ADH in textiles was in the range of 85-100%, and the RSD (relative standard deviation) was less than 10%. The ADH-positive textile samples were placed in designed environments for some time to adsorb formaldehyde. The adsorbed amounts of formaldehyde in the textile samples first increase and then decrease with time. The maximum amount of formaldehyde a sample can adsorb increases with an increase in its ADH content and will stop increasing once its ADH content exceeds 1700 mg kg-1. The placement environment has a little effect on the maximum adsorption capacity of the samples towards formaldehyde, but can significantly affect the adsorption rate and equilibrium adsorption capacity.

Inactivation and degradation of Microcystis aeruginosa by UV-C irradiation.

In this study, the mechanisms and factors affecting the inactivation and degradation efficiency during UV-C irradiation of Microcystis aeruginosa, a harmful cyanobacteria strain, were investigated. Under different experimental conditions, the concentrations of three bioactivity materials, including protein, phycocyanin and chl-a, were measured, and fluorescence regional integration (FRI) was used to quantify the results of excitation emission matrix fluorescence spectroscopy. Furthermore, any alternation occurring in cell ultrastructure was determined using transmission electron microscopy. Results showed that UV-C could effectively damage the M.aeruginosa cells, most likely via a 3-step procedure, including impairment of photosynthesis system, decomposition of cytoplasmic inclusions, and cell cytoclasis. Comparison of FRI values and biochemical parameters in the presence of H(2)O(2) and HCO(3)(-) under the UV-C irradiation revealed the importance of photolysis and reactive oxygen species (ROS)-induced oxidation. UV-C/H(2)O(2) treatment was more efficient due to enhanced ROS generation, while adding HCO(3)(-) inhibited the ROS-induced oxidation, resulting in suppression on reaction. Humic acid and NO(3)(-), two common water solutes, somewhat inhibited the inactivation and degradation processes, due to the ROS scavenging and "inner filter" effect.

pH sensitive alginate-chitosan hydrogel beads for carvedilol delivery.

Alginate-chitosan hydrogel beads for carvedilol delivery were prepared to be used as a controlled pH-sensitive drug delivery system. The beads were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The swelling ability and in vitro release of carvedilol in solutions of different pH value were investigated. They exhibited significant swelling rates when exposed to the slightly alkaline environment. The results suggest that the system has potential to be used as an effective pH-controlled delivery system for carvedilol. The release of carvedilol at various pH values was analyzed by a semi-empirical equation.