气相色谱-负化学离子源质谱法测定聚氯乙烯塑料中的短链氯化石蜡

建立了用于聚氯乙烯(PVC)塑料中短链氯化石蜡(SCCPs)含量测定的气相色谱-负化学离子源质谱法。采用超声萃取法对PVC塑料中的SCCPs进行萃取,萃取时间为1.5 h;然后用浓硫酸法对萃取溶液进行净化处理;最后用气相色谱-质谱法在负化学电离模式、离子源温度为160 ℃、甲烷反应气流速为1.5 mL/min等条件下对样品中的SCCPs进行定性定量分析。该方法不受样品中中链氯化石蜡(MCCPs)的干扰,可对样品中的SCCPs进行准确的定量分析。分析的12批次样品均检出SCCPs,含量在0.3×10²~3.5×10⁴mg/kg范围内。依据欧盟对SCCP的限值(1%)要求,4批次样品不符合法规要求,不符合率为33.3%。可见,PVC塑料具有较高的SCCPs污染风险。     

Waste poly(vinyl chloride) pyrolysis with hydrogen chloride abatement by steelmaking dust

Experimental study on PVC-based materials (PVC = poly(vinyl chloride)) pyrolysis; in the presence of various amounts of steelmaking dust was performed. Dust from steel manufacture employing zinc plated scrap contains a considerable amount of zinc oxide (ZnO) and its utilization in metallurgy is quite complicated. However, the dust can react with hydrogen chloride (HCl) released from heated PVC in the temperature range of 200–400°C. Material balance of the pyrolysis process was studied by thermogravimetry, and the data obtained were compared with the results of larger laboratory oven experiments. In excess of PVC, the amount of captured HCl stoichiometrically corresponds to the content of ZnO; additional HCl is probably captured by FeCl₂, while FeCl₃ is not formed at elevated temperatures. In excess of the dust, the captured amount of HCl is approximately 100%. The suggested co-pyrolysis seems to be a promising method to prevent the formation of dangerous chlorinated organic compounds during the thermal treatment of waste PVC. Furthermore, the obtained ZnCl₂ is a valuable material and the zinc depleted dust can be reused in metallurgy instead of its disposal.     

Analytical method development for 18 pesticides in house dust and settled residues using SEC, SPE, TMS methylation, and GC-MS

An analytical method is developed to analyze eighteen pesticides in carpet dust and also dust that has settled on surfaces in order to determine the potential exposure of children to pesticide residues. For nonacid pesticides, the extract after centrifugation and filtration is cleaned up using size-exclusion chromatography (SEC) and then analyzed by gas chromatography (GC) coupled with a mass spectrometer (MS). The best solvent for extraction is ethyl acetate-cyclohexane (3:1). The recoveries of spiked nonacid pesticides from 2 g of dust are between 72% and 110% with a variation between 4.2% and 25.6%, and the detection limit is 10 to 50 ng/g dust, depending on the pesticide. For acid pesticides, the dust is extracted with a saturated Ca(OH)2 solution, centrifuged, cleaned up by polyvinylbenzene/polystyrene-type solid-phase extraction cartridges, and methylated with trimethylsilyldiazomethane (TMS). Acid pesticides on filter paper samples are extracted with acidified acetone (3 mM H3PO4) and methylated with TMS. Methylation with TMS is fast and easy to perform. Methyl esters of the pesticides are completely separated and detected at low levels by GC-MS in the selective ion monitoring mode. The average recoveries of pesticides from 2 g of dust are between 81% and 104%. The average recoveries of pesticides spiked on filter paper are between 88% and 113%. A capillary column with a stationary phase of trifluoropropylmethyl polysiloxane gives the best separation and sensitivity for most pesticides on the GC-MS.     

The use of chemical modifiers in the determination of cadmium in sewage sludge and tin in PVC by solid sampling-graphite furnace atomic absorption spectrometry

The effects of NH₄H₂PO₄ and Pd as chemical modifiers in SS-GFAAS are studied in the determination of Cd in sewage sludge and of Sn in PVC samples. Whereas for Cd both modifiers act equally well whether Cd is in solution or in the solid sample, the effect of Pd on tin is different. To make the Pd modifier as effective on Sn in PVC as on Sn in solution a two-step pyrolysis must be introduced into the temperature programme. It is also shown that the contribution of the application of chemical modifiers to the final imprecision of the determination is negligible compared to that introduced by the sample inhomogeneity.     

Broad line NMR investigation of compatibility using powdered and milled samples of PVC and EVA, and the effects of heat-treatment

The limited miscibility of poly(vinyl chloride) (PVC) and ethylene-vinyl acetate copolymer (EVA) observed for milled samples has now been demonstrated for samples in powdered form by means of broad line NMR. The changes in the phase relations are mainly dependent on two processes, viz. the phase separation and the development of the interactions between PVC and EVA chains. The stable level of the phase relations is dependent upon the thermal history. We assume this to be an effect of the varying degrees of entanglement between PVC and EVA chains. It has also been demonstrated that the fraction of EVA staying in the free phase increases both for the milled and powdered samples when the degree of grafting between PVC and EVA decreases. A method for the quantitative investigation of the solubility conditions of polymer two-phase systems in bulk is also presented.     

Quantitative analysis of polycyclic aromatic hydrocarbons in sewage sludge from wastewater treatment plants.

Polycyclic aromatic hydrocarbons (PAHs) are an important group of organic contaminants present in sewage sludge. Due to their persistence and toxic potential, information about their presence in sewage sludge is needed in order to assess applicability on agricultural land. A method for the gas chromatographic-mass spectrometric (GC-MS) determination was developed and applied to the trace determination of PAHs present in sewage sludge samples from six wastewater treatment plants (WWTPs) differing in the type of treatment and the origin of wastewater. PAHs were extracted from freeze-dried samples by a dichloromethane-methanol (2:1) mixture in a sonication bath. The sludge extracts were cleaned-up by an alumina column. The method showed recovery values varying from 60 to 98%. Four surrogate standards ([2H8]naphthalene, [2H10]anthracene, [2H12]benzo[a]anthracene, and [2H12]benzo[ghi]perylene) were used for quantitation by GC-MS. A reference sludge sample was analysed in order to validate the method. The sum of the 16 US Environmental Protection Agency PAHs analysed in the sewage sludge samples varied from 1.13 to 5.52 mg/kg. No significant difference between the different WWTPs was found.     

Comparison of two extraction methods for the analysis of per- and polyfluorinated chemicals in digested sewage sludge

A rapid and reliable analytical method, based on ion-pair extraction, clean-up on Envicarb cartridge and detection by liquid chromatography–tandem mass spectrometry (LC–MS/MS), was developed for determination of 17 per- and polyfluorinated chemicals (PFCs) in digested sewage sludge. Envicarb cartridge and six labeled internal standards were selected for the elimination/reduction and correction of matrix effects, respectively. As a result, the matrix effect for perfluorooctane sulfonamides (FOSAs) and perfluorocarboxylic acids (PFCAs) with carbon chain length from C6 to C14 was lowered to a range of −14% to +28%. However, the matrix effect for other analytes was still great mainly due to the absence of appropriate internal standard. Mean recoveries of the target analytes based on matrix spikes, at different spike levels (10–300 ng/g), ranged from 70% to 169%. Relative standard deviations (RSDs) were in the range of 2–20% at different spike levels. The limit of quantification (LOQ) ranged between 0.6 and 30 ng/g. The method was successfully applied to several sewage sludge samples from wastewater treatment plants nearby Zürich, Switzerland. In addition, by comparing the accuracy and precision of ion-pair extraction method and methanol extraction method, we further demonstrated that the ion-pair extraction method can be used for the analysis of PFCs in sludge samples. To our knowledge, this is the first study to extract the PFCs in sewage sludge with ion-pair method and to find unsaturated fluorotelomer carboxylic acids (FTUCAs) in sewage sludge.     

Simple approach for the determination of brominated flame retardants in environmental solid samples based on solvent extraction and solid-phase microextraction followed by gas chromatography-tandem mass spectrometry

A viable approach for the analysis of polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) in sewage sludge samples is presented in this paper. The proposed method combines ultrasound-assisted extraction (UAE) of the solid sample and headspace solid-phase microextraction (HS-SPME) of the obtained extract, followed by gas chromatography coupled to tandem mass spectrometry (GC-MS-MS) analysis. Different parameters affecting the extraction process are evaluated and optimized. The addition of a small amount of Florisil to the sample during UAE provides a significant improvement of the chromatographic background and, at the same time, a much more efficient HS-SPME. Extensive method validation is performed using real sewage sludge samples. The proposed method exhibits good performance in terms of linearity and precision, with recoveries exceeding 92% and limits of detection in the sub ng g(-1) level. Practical applicability is demonstrated through the analysis of real contaminated sewage sludge and sediment samples in which some of the target PBDEs are detected and quantified. This proposed combined methodology represents a large time-saving when compared to other classic multi-step solvent extraction methods and it constitutes a suitable approach for the analysis of the target compounds in environmental complex solid samples.     

Determination of polybrominated diphenyl ethers in domestic dust by microwave-assisted solvent extraction and gas chromatography-tandem mass spectrometry

In this paper, a rapid and simple method for the analysis of polybrominated diphenyl ethers (PBDEs) in house dust samples based on microwave-assisted solvent extraction (MASE) and gas chromatography-tandem mass spectrometry (GC-MS/MS) is presented. Extraction conditions were optimized using a multifactorial experimental design approach. The use of an aqueous NaOH phase in combination with a non-polar organic phase (hexane) to extract the target analytes from dust allowed an efficient extraction and reduced chromatographic background. The final hexane extracts could be analyzed after a simple one-step cleanup procedure using Florisil. The validation of the method was performed in terms of accuracy, linearity, and repeatability. The limits of detection (LODs) ranged from 0.29 to 0.55 ng/g for all compounds. The target PBDEs were found in several real dust samples collected in urban and rural houses of Northwestern Spain.     

Determination of synthetic musk compounds in indoor house dust by gas chromatography–ion trap mass spectrometry

A new method for the simultaneous determination of 11 synthetic musks and one fragrance compound in house dust was developed. The nitro musks included musk ketone (MK, 4-tert-butyl-3,5-dinitro-2,6-dimethylacetophenone), musk xylene (MX, 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene), musk ambrette (1-tert-butyl-2-methoxy-4-methyl-3,5-dinitrobenzene) and musk moskene (1,1,3,3,5-pentamethyl-4,6-dinitroindane). The polycyclic musk compounds were 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(γ)-2-benzopyran (HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), 4-acetyl-1,1-dimethyl-6-tert-butylindane, 6-acetyl-1,1,2,3,3,5-hexamethylindane, 5-acetyl-1,1,2,6-tetramethyl-3-isopropylindane, 6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)-indanon. The one macrocyclic musk was 1,4-dioxacycloheptadecane-5,17-dione. The bicyclic hydrocarbon fragrance compound (1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethylnaphthalen-2yl)ethan-1-one (OTNE) and HHCB-lactone (4,6,6,7,8,8-hexamethyl-1H,3H,4H,6H,7H, 8H-indeno[5,6-c]pyran-1-one), a degradation product of HHCB, were also analysed. NIST SRM 2781 (domestic sludge) and SRM 2585 (organic contaminants in house dust) were analysed for these target compounds. The method was applied for the analysis of 49 paired samples collected using two vacuum sampling methods: a sample of fresh or "active" dust (FD) collected using a Pullman-Holt vacuum sampler, and a household dust (HD) sample taken from the participants' vacuum cleaners. Method detection limits and recoveries ranged from 12 to 48?ng/g and 54 to 117?%, respectively. AHTN, HHCB, OTNE and HHCB-lactone were detected in all samples, with median concentrations of 552, 676, 252 and 453?ng/g for FD samples, respectively; and 405, 992, 212 and 492?ng/g for HD samples, respectively. MX and MK were detected with high frequencies but with much lower concentrations. The two sampling methods produced comparable results for the target analytes. Widely scattered concentration levels were observed for target analytes from this set of 49 house dust samples, suggesting a wide variability in Canadian household exposure to synthetic musks.     

Bulk and compound-specific isotopic characterisation of illicit heroin and cling film

Comparative analysis involves various but complementary methods and can be used for forensic intelligence purposes to group seizures of heroin into batches. Much forensic analysis now combines expertise in the traditional area of drugs investigation with a detailed understanding of supply, packaging, distribution, and drugs intelligence. It was the intention of this research to determine whether illicit heroin seizures and packaging material can be grouped according to isotopic compositions, and to explore factors that affect the isotopic compositions. In order to achieve these aims, 14 samples of seized heroin, thirteen provided by Avon and Somerset Constabulary (UK), were analysed by elemental analysis/isotope ratio mass spectrometry (EA/IRMS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) for carbon and hydrogen isotopes. These tests elucidated that a combination of the delta13C, delta15N, delta18O and delta2H results from EA/IRMS is able to distinguish between most samples of bulk heroin. We speculate that the delta13C values of the alkaloids, obtained by GC/C/IRMS, give indications of different geographical or temporal origins of some of the heroin samples. GC/C/IRMS of the cutting agent, caffeine, provides a means to link dilution events. Fifteen retail cling film samples and seven cling film samples from heroin seizures were analysed by EA/IRMS. A multivariate comparison of the carbon, hydrogen and oxygen isotope ratios was able to distinguish between most of the samples. This technique enabled the cling films from the heroin to be grouped according to seizure. Three solvents were tested on two samples of cling film of known composition. Methanol and chloroform were both found to extract material from PVC and from non-PVC cling films. Water-treated PVC was indistinguishable from the untreated PVC and thus water was found to be the most suitable solvent when washing cling film prior to IRMS analysis.     

Activity profile of dust mite allergen extract using substrate libraries and functional proteomic microarrays

Enzymatic activity in the fecal droppings from the house dust mite has been postulated to contribute to the elicited allergic response. Screening dust mite extracts through 137,180 tetrapeptide fluorogenic substrates allowed for the characterization of proteolytic substrate specificity from the potential cysteine and serine proteases in the extract. The extract was further screened against a 4000 member peptide nucleic acid (PNA) encoded inhibitor library designed to target cysteine proteases using microarray detection. Affinity chromatography coupled with mass spectrometry identified Der p 1 as one of the proteases targeted by the PNA inhibitors in the dust mite lysate. A phenotypic readout of Der p 1 function in allergy progression was demonstrated by the inhibition of CD25 cleavage from T cells by dust mite extract that had been treated with the Der p 1 inhibitor identified from the PNA-encoded inhibitor library.     

Nanotubes as polymer composite reinforcing additive materials – A comparative study

Nitrogen-doped bamboo-shaped carbon nanotubes (N-BCNTs) and their non-doped conventional counterparts, multiwalled carbon nanotubes (MWCNTs) were compared as polymer reinforcing additives in polyvinyl chloride (PVC) matrix. The nanotubes were synthetized by catalytic chemical vapor deposition (CCVD) method. The purity of both nanotubes was measured by thermogravimetric analysis (TGA) and found to be >91%. Further analysis on the morphology and size of the carbon nanotubes (CNTs) were performed by transmission electron microscopy (TEM). The PVC powder was impregnated with CNTs in ethanol by using tip ultrasonicator. The dispersion media was evaporated, and the CNT/PVC powder was used to produce polymer fibers. The orientation of carbon nanotubes in the PVC matrix was characterized by scanning electron microscopy (SEM), and the presence of nanotubes were confirmed in case of all PVC samples. It can be observed on the SEM images that the nanotubes are fully covered with PVC. The tensile strength of the nanotube containing samples was tested and the N-BCNT/PVC composite was found to be better in this sense, thanks to the extraordinary structure of the nanotube. In case of the N-BCNT/PVC composite the measured young modulus was 39.7% higher, while the elongation at brake decreased by 33.6% compare to the MWCNT/PVC composite. These significant differences in the mechanical properties of the composites can be explained with the stronger interaction between N-BCNTs and PVC.     

Leachability of naturally occurring radioactive materials

Summary Naturally occuring radioactive materials (NORM) are present in the environment and can be concentrated by technical activities, particularly those involving natural resources. These NORM deposits are highly stable and very insoluble under environmental conditions at the earth's surface. However, reducing or oxidant conditions or pH changes may enable a fraction of naturally occurring radionuclides to eventually be released to the environment. In this paper the leachability of²¹⁰Pb and²¹⁰Po was determined in three samples coming from a refractories production plant (dust, sludge, finished product), in one dust sample from a steelwork and in one ash sample coming from an electric power station. A sequential extraction method consisting of five operationally-defined fractions was used. The average leaching potential observed in the samples from the refractory industry is very low (mean values: 5.8% for²¹⁰Pb and 1.7% for²¹⁰Po). The²¹⁰Pb and²¹⁰Po leachability increases for the ash sample coming from an electric power plant using carbon (17.8% for²¹⁰Pb and 10.0% for²¹⁰Po); for the dust sample coming from a steelwork, the percent soluble fraction is 41.1% for²¹⁰Pb and 8.5% for²¹⁰Po. For all samples the results obtained show that²¹⁰Pb is slightly more soluble than²¹⁰Po.     

Determination of perfluorooctanesulfonate and perfluorooctanoic acid in sewage sludge samples using liquid chromatography/quadrupole time-of-flight mass spectrometry

A new method is developed for the determination of perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) in sewage sludge samples. The analytes in sewage sludge samples are extracted by methanol and formic acid, cleaned by C18 solid-phase extraction, then separated, identified and quantitated by liquid chromatography/quadrupole time-of-flight mass spectrometry (LC–QTOF-MS). A C18 column (150 mm × 2.1 mm, 3.5 μm) with gradient elution of MeOH–H₂O (60:40) containing 5 mmol/L ammonium acetate and MeOH–H₂O (80:20) is used for the chromatographic separation. [M−K]⁻ ions at m/z 498.93 for PFOS and [M−COOH]⁻ ion at m/z 368.97 for PFOA are selected for QTOF-MS in the negative electrospray ionization mode. The detection limits for PFOS and PFOA in sewage sludge samples are 0.5 and 0.8 ng/g, respectively. The spiked recoveries are in the range of 85–114 and 71–98% for PFOS and PFOA, respectively. The proposed method is successfully applied to the analysis of PFOS and PFOA in 16 sewage sludge samples from China. PFOS and PFOA are detected in most sewage sludge samples and the concentrations of PFOS and PFOA are up to 5383 and 4780 ng/g (oven dry weight), respectively.     

Copper nanoparticles seeded functionalized‐PVC plastic surface for electroless nickel deposition

A novel and facile activation process for electroless nickel deposition was developed. The semi‐interpenetrating polymer network hydrogel biofilm was used to functionalize the inert poly(vinyl chloride) (PVC) surface, and then Cu nanoparticles, which can initial the subsequent electroless nickel deposition successfully seeded on the functionalized‐PVC surface. The samples were characterized by scanning electron microscopy, X‐ray photoelectron spectroscopy, X‐ray diffraction, and transmission electron microscopy. The results show that the hydrogel film provided the PVC surface with amino groups and Cu nanoparticles of 20–50 nm in size could be functioned as the catalytic nuclei for the subsequent electroless metal deposition on PVC plastic. It can be concluded that the novel Cu activation was effective for the nickel deposition on PVC surface, because of more chemisorption sites for Cu nanoparticles generated on PVC surface. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of PAHs in dust from Shanghai by optimized SFE and GC/MS

EPA 16 priority polycyclic aromatic hydrocarbons (PAHs) were extracted from dust by supercritical fluid extraction (SFE). Parameters (pressure, temperature and time) affecting the collection efficiencies of PAHs were assessed according to the extraction efficiency, and 30 MPa, 80 degrees C and 30 min dynamic extraction time were confirmed to be the best and simplest conditions of SFE to extract 16 priority PAHs from dust. The characterization of the extracts was carried out by gas chromatography with mass detector in selective ion mode (GC/MS/SIM). Ultrasonic extraction (USE) was used as a comparison with SFE. The results showed that the SFE method has a better efficiency than USE for the extraction of PAHs in dust. With the optimized conditions of SFE, the distribution of PAHs in dust samples in urban areas of Shanghai from Mar 10, 2005 to May 28, 2005 was investigated. The results demonstrated that traffic emission, especially from gasoline engines, was the main source of PAHs in dust of Shanghai.     

Simultaneous determination of hexabromocyclododecane, tetrabromobisphenol A, and related compounds in sewage sludge and sediment samples from Ebro River basin (Spain)

This paper describes the development of a methodology for the simultaneous determination and quantification of hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), and related compounds (bisphenol A, monobromobisphenol A, dibromobisphenol A, and tribromobisphenol A) in sludge and sediment samples. The selected method is based on an extraction with dichloromethane: methanol followed by purification via SPE C₁₈ cartridges. Instrumental determination was carried out by liquid chromatography–quadrupole linear ion trap mass spectrometry (LC-QqLIT-MS), with quantification based on isotopic dilution method. Analyte recoveries were in the range of 39–120% and 88–126% for spiked sewage and sediment, respectively. Repeatability of replicate extractions was better than 13% relative standard deviation. Linearity was checked in the range of 0.05 and 25 injected nanograms. Limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.6 and 2.7 ng/g and 1.4 and 66 ng/g for sediment and sludge samples, respectively. The developed method was applied to sewage sludge and sediment samples collected along the Ebro River and Cinca River, one of its tributaries (northeast of Spain). TBBPA levels in sewage sludge ranged from not quantified to 1,329 ng/g dw, whereas levels in sediment samples were lower, between not detected and 15 ng/g dw. As regards HBCD, concentrations were between not detected and 375 ng/g for sludge samples and 0.8 and 1850 ng/g for sediments.     

Detection of the cyclic nitramine explosives hexahydro-1,3,5-trinitro- 1,3,5-triazine (RDX) and octahydro- 1,3,5,7-tetranitro- 1,3,5,7-tetrazine (HMX) and their degradation products in soil environments

The cyclic nitramine explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX) were examined in field and microcosm soil samples to determine their patterns of degradation and environmental fates. A number of analytical techniques, including solid-phase microextraction with on-fiber derivatization, gas chromatography-mass spectrometry, gas chromatography with electron-capture detection, liquid chromatography-mass spectrometry, and micellar electrokinetic chromatography were required for the analyses. Two different classes of intermediates were detected, both of which lead ultimately to the formation of nitrous oxide (N2O) and carbon dioxide (CO2). The first class was identified as the nitroso derivatives formed by the sequential reduction of -NO2 functional groups. The second class of intermediates, which was favored at higher humidities and in the presence of anaerobic sludge amendments, consisted of ring cleavage products including bis-(hydroxymethyl)-nitramine and methylenedinitramine. Rye-grass (Lolium perenne) present in field samples was found to extract and accumulate HMX from soil without further degradation. In all cases (excepting the plant samples), the indigenous microbes or amended domestic anaerobic sludge consortia degraded the cyclic nitramine explosives eventually to produce N2O and CO2.     

聚氯乙烯结构缺陷和热不稳定性之间关系的研究 2.各种结构缺陷含量和热脱氯化氢速率之间的关系

本工作采用溴加成法、酚解法、FTIR法及臭氧裂解法分别测定了五种不饱和蒸气压下聚合的PVC样品(u-PVC)和五种商品PVC样品(s-PVC)的总双键、总不稳定氯、孤立双键和内部双键的含量.通过研究结构缺陷和PVC的平均分子量及脱HCl速率的相互关系,揭示了不饱和总双键值,总不稳定氯和孤立双键含量彼此的相关性是建立在它们分别与1/M_n的相关性基础之上,从而得出了这三种定量值测得的主要都是端基烯丙基氯结构.根据三者对脱HCl速率的良好线性相关性,首次提出了端基烯丙基氯结构在HCl催化作用下异构化成内部烯丙基氯从而成为脱HCl速率主要原因的机理.