Determination of extractable organohalogens in the atmosphere by instrumental neutron activation analysis

Summary Air samples were collected at a downtown site in Beijing from January to July 2004 and analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction method for the concentrations and distributions of extractable organohalogens (EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and organoiodinated compounds (EOI). The concentrations of EOX were increasing in the order of EOCl >> EOBr ~ EOI in both gaseous and particulate phase. EOCl accounted for 75.8-100% and 83.7-100% of EOX in particulate and gaseous phase, respectively, suggesting that EOCl was the major component of the organohalogens in the atmosphere. In the plots of the logarithm of the EOX concentrations versus the reciprocal temperature, their linear relations were observed for EOCl (R = -0.9), for EOBr (R = -0.6) and EOI (R = -0.7) in gaseous phase, which indicated that the concentrations of EOCl, EOBr and EOI in gaseous phase exhibited a strong temperature dependence, i.e., their concentrations increased with increasing of temperature.     

Recent trends of plutonium fallout observed in Japan: Comparison with natural lithogenic radionuclides, thorium isotopes

PM_2.5 and PM₁₀ samples were simultaneously collected monthly at a downtown site in Beijing from May 2002 to April 2003 and analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction method for the concentrations and distributions of extractable organohalogens (EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and organoiodinated compounds (EOI). The concentrations of EOCl, EOBr and EOI were 10.5–79.2 ng/m³, ND-8.2 ng/m³ and 1.6–8.2 ng/m³ in PM_2.5, respectively, and 37.0–73.3 ng/m³, 1.6–12.8 ng/m³ and 1.6–8.5 ng/m³ in PM₁₀, respectively, which were increasing in the order of EOCl≫EOBr∼EOI. EOCl accounted for 73–88% and 69–91% of EOX in PM_2.5 and PM₁₀, respectively, which showed that EOCl was the major component of the organohalogens. There was a significant difference of EOCl concentrations in PM_2.5 and PM₁₀ in different seasons, which suggested that the concentrations of EOCl in the atmosphere were significantly affected by the meteorologic conditions and anthropogenic activities.     

Instrumental Neutron Activation Analysis of Extractable

Instrumental neutron activation analysis was performed to measure the levels of extractable organohalogens (EOX) in the organisms from the Antarctic marine ecosystem. The results show that EOX (EOCl, EOBr and EOI) were found in all the samples analyzed. The highest concentration was determined in the ascidian sample. The concentration order of EOX was mainly EOCl>EOBr>EOI with the exception of nemertine, ascidian, fish and adelie penguin samples. The concentrations of man-made organochlorines (DDTs and CHLs) were analyzed by GC-MS, and the results were compared with the concentrations of EOX determined in the same samples. The results show that the contribution of known man-made organochlorines in EOCl was less than 3%. This means that a large amount of unknown organochlorine compounds is present in Antarctic marine organisms.     

Instrumental neutron activation analysis of extractable organohalogens in the Antarctic Weddell seal (<Emphasis Type="Italic">Leptonychotes weddelli</Emphasis>)

Instrumental neutron activation analysis (INAA) was performed for measurement of extractable organohalogens (EOX) in blubber samples of Weddell seals (Leptonychotes weddelli) from Antarctica. EOX were detected in all the analyzed samples. The concentration order of EOX was: extractable organochlorine (EOCl)>extractable organobromine (EOBr)>extractable organoiodine (EOI). Their levels increased gradually with aging as with other man-made persistent organic pollutants (POPs) such as PCBs and DDTs.     

Instrumental neutron activation analysis of extractable organohalogens in marine mammal,harbour porpoise (<Emphasis Type="Italic">Phocoena phocoena</Emphasis>) and its feed,Atlantic herring (<Emphasis Type="Italic">Clupea harengus</Emphasis>), from the Baltic Sea

Instrumental neutron activation analysis (INAA) was conducted for the analysis of extractable organohalogens (EOX) in the blubber samples of harbour porpoise (Phocoena phocoena) and whole body samples of Atlantic herring (Clupea harengus) from the Baltic Sea. The concentration order of EOX was: extractable organochlorine (EOCl) > extractable organobromine (EOBr) > extractable organoiodine (EOI). As the results of investigation into the biomagnification properties of EOX, EOBr in low molecular weight fraction was the highest among the organic halogens investigated, suggesting the presence of high persistent organic bromine compounds in the marine environment, and accumulation through food chains.     

Study of organohalogen contaminants in yogurt by NAA and GC-ECD

The concentrations and distributions of total halogen (TX), extractable organohalogen (EOX) and extractable persistent organohalogen (EPOX) were determined in 20 kinds of yogurt specimens collected from Chinese supermarkets using neutron activation analysis (NAA) and gas chromatography equipped with a ⁶³Ni electron capture detector (GC-ECD). The results indicated that the halogens in yogurt mainly existed as non-extractable organohalogen compounds. About 25–30% of EOX was EPOX. EOCl and EPOCl were the main organohalogen species in yogurt. The average concentration of the identified organochlorine, such as organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), was below 4% of EPOCl.     

INAA for the determination of extractable organohalogens in precipitation in Shanghai, China

The paper presents the results of determination of extractable organohalogens (EOX) by instrumental neutron activation analysis (INAA), and polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) by gas chromatography (GC), in atmospheric precipitation in Shanghai, China, from January to August 2005. The results showed that EOCI was the major component of organohalogens in precipitation. A significant correlation between the concentrations of EOBr and EOI was observed (r ² = 0.75), which suggested that EOBr and EOI in precipitation might mainly come from the same sources. There were no clear seasonal trends for the concentrations of EOX. The concentrations of ΣPCBs ranged from 0.2–2.8 ng/l, with the dominant PCBs containing 3 to 5 chlorine atoms. HCH was the predominant pesticide in precipitation, accounting for over 80% of total OCPs, in which β-HCH took 28%–72% of total HCH. Also, there may be an evidence for significantly historical usage of DDT.     

Hybrid NAA method for assessment of the levels of organic halogen compounds in the atmosphere in China

Abstract Passive air samplers (polyurethane foam disks) were deployed at 25 urban sites and 66 rural sites over the period of July to October 2005, partly between October 2005 and January 2006 for about 120 days across China, and analyzed for extractable organo-chlorine /-bromine /-iodine (EOCl/EOBr/EOI) and polychlorinated biphenyls (PCBs) using hybrid neutron activation analysis (NAA) combined with gas chromatographymass spectrometry (GC-MS). The average concentration of EOCl, EOBr, EOI and ΣPCBs among all the sites were 173.7, 3.5, 1.0 and 0.74 ng/d, respectively. Higher values of EOCl/Br/I and PCBs were detected in the areas of high usage and high emission, which were linked to relatively high-income areas in China, while lower in the west ill-developed region of China, which indicated that these pollutants mainly came from industrial pollution. Higher EOCl contents in traffic areas stated that the exhaust emission from vehicle was another main source of organochlorines in the air. The relative proportions of the known organochlorines (84 PCB congeners) to total EOCl were 0.02–3.0%, which implied that most of EOCl measured in air were unknown.     

Maternal body burden of organochlorine pesticides and dioxins.

To investigate the body burden of organochlorine pesticides and dioxins in Japanese women, 125 milk samples were collected from 41 mothers in 1994, 42 in 1995, and 42 in 1996. Of the 125 samples, 82 were from primipara mothers (first delivery) and 43 were from multipara mothers (second or later delivery). By using capillary gas chromatography with electron capture detection, beta-HCH and p,p'-DDE were detected as the major chlorine pesticides in human milk. Average levels of beta-HCH and p,p'-DDE were 475 and 368 ng/g lipid, respectively, in primipara breast milk, 314 and 259 ng/g lipid in multipara breast milk, and 420 and 330 ng/g lipid in total breast milk. Dieldrin, heptachor epoxide, oxychlordane, trans-chlordane, and cis-chlordane were detected at lower average levels of 3, 4, 34, 41, and 5 ng/g lipid, respectively. By using high-resolution gas chromatography with mass spectrometric detection, dioxins were detected in all samples. Average levels of total polychlorinated dibenzo-p-dioxin (PCDD), total polychlorinated dibenzofuran (PCDF), total PCDD + PCDF, total coplanar polychlorinatedbiphenyl (CoPCB), and total dioxin were 10.0, 7.8, 17.7, 9.9, and 27.5 TEQ (toxic equivalent) pg/g lipid, respectively, in primipara breast milk; 7.0, 5.8, 12.8, 7.3, and 20.1 TEQ pg/g lipid in multipara breast milk; and 8.9, 7.1, 16.1, 8.9, and 25.0 TEQ pg/g lipid in total breast milk. In primipara breast milk, significant correlations were found among levels of beta-HCH, p,p'-DDE, total PCDD-TEQ, total PCDF-TEQ, total CoPCB-TEQ, and total TEQ except for less correlation between p,p'-DDE and total PCDF-TEQ. Levels of these analytes also significantly increased depending on mother's age, except for total Co-PCB-TEQ. For the correlation with food habit, the only positive correlation was between total PCDF-TEQs and fish intake.     

Neutron activation analysis of organohalogens in Chinese human hair

To effectively extract organohalogens from human hair, two factors, the extracting time and hair length on the extraction efficiency of organohalogens were studied by neutron activation analysis (NAA) and gas chromatograph-electron capture detector (GC-ECD), respectively. Furthermore, the concentrations of extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX) in hair samples from angioma and control babies were also measured by the established method. The results indicated that the optimal Soxhlet-extraction time for EOX and EPOX in hair was from 8 to 11 hours, and the extraction efficiencies for organochlorine pesticides in hair were in the order of powder >2 mm>5 mm. Also, the mean levels of EOC1 and EPOC1 in hair of the angioma babies were significantly higher than those in the control babies (P _EOC1<0.01; P _EPOC1<0.05), which implied the possible relationship between the environmental pollution and angioma.     

Determination of chloramphenicol in milk by a fluorescence polarization immunoassay

A procedure for the determination of the drug chloramphenicol using a fluorescence polarization immunoassay (FPIA) was proposed. The optimum pairs of antibodies and antigens labeled with fluorescein were chosen, and the analytical characteristics of the procedure were determined. A rapid procedure for milk sample preparation with the use of a saturated solution of ammonium sulfate was optimized. The total time of sample preparation and determination of chloramphenicol in milk was no longer than 10 min. The detection limits of chloramphenicol in water and milk were 10 ng/mL and 20 μg/kg, respectively. The procedure developed for the determination of chloramphenicol was tested in the analysis of model and real milk samples. It was found that some milk samples contained chloramphenicol in concentrations of 38–41 μg/kg, which are several times higher than the maximum permissible concentration (MPC) (10 μg/kg).     

Determination of pesticides and some metabolites in different kinds of milk by solid-phase microextraction and low-pressure gas chromatography-tandem mass spectrometry

A new analytical method is proposed to determine more than 40 multiclass pesticides in different kinds of processed (whole, skimmed and powdered) and unprocessed (goat and human) milk samples using solid-phase microextraction (SPME). A comparative study between headspace (HS) and direct immersion (DI) was carried out. The effect of milk dilution and the use of acid to reduce the influence of the matrix in DI-SPME mode were also evaluated. DI of the SPME fiber into previously diluted and acidified milk samples achieved the best sensitivity results. Pesticides were determined using low-pressure gas chromatography-tandem mass spectrometry (LP-GC-MS/MS). Both of the selected techniques have been shown to be effective at reduce fat interference and can determine analytes present at very low concentrations (limits of quantification between 0.02 and 1.00 g L^–1). Performance characteristics such as linearity, recovery, precision, and lower limits, together with an estimation of the measurement uncertainty using validation data, are presented for each pesticide. All of the pesticides presented recovery rates of between 81 and 110% and precision values lower than 12% (expressed as the relative standard deviation). The overall uncertainty of the method was estimated at three different concentrations (10, 25 and 50 g L^–1) and was lower than 25.5% in all cases. The proposed analytical methodology was applied to the analysis of target pesticides in 35 samples: 15 commercial, 3 human and 17 goat milk samples. The metabolite p,p-DDE was the compound most frequently found in both the breast and goat milk samples, at concentration levels <20 g L^–1. However, pesticide residues were not found in any of the other 15 commercial milk samples (skimmed, powdered and whole milk) analyzed.     

Method validation,residue analysis and dietary risk assessment of trifloxystrobin and trifloxystrobin acid in milk,eggs and pork

Trifloxystrobin (TFS) is a widely used strobilurin fungicide and its residues accumulating in animal-derived food could result in potential harm to consumers. By optimization of extraction solvents and cleanup sorbents, a residue analysis method for TFS and its metabolite trifloxystrobin acid (TFSA) was established in milk, eggs and pork based on QuEChERS sample preparation and LC–MS/MS. The calibration curves exhibited good linearity with determination coefficients (R²) >0.9930 over the range of 0.5–250 ng/ml for both TFS and TFSA. The recoveries of the two analytes were 81–100% with RSD 3–10% and 76–96% with RSD 2–13%, respectively. The limit of quantification (LOQ) was 1 ng/g for both analytes. The milk, egg and pork samples, 30 each, were collected from the 30 main producing regions in China, and residues of TFS and TFSA were analyzed. The concentrations of both analytes were lower than the corresponding LOQs and maximum residue limits. Long-term dietary risk assessment showed that the hazard quotients were 0.001–0.003%, indicating an absence of unacceptable risks in milk, eggs and pork to the health of common consumers in China.     

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78?% to 121?%. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145?ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2?ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045?±?0.023?ng/g. Mean concentrations of PFOA were not significantly different (p?>?0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032?ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.     

Residues of 165 pesticides in citrus fruits using LC-MS/MS: a study of the pesticides distribution from the peel to the pulp

Abstract

A sensitive LC–ESI-MS/MS method was developed for the determination of 165 pesticides in 50 citrus fruit samples collected in Sicily. Moreover, an evaluation of pesticides levels in the citrus layers (peel, albedo, and pulp) was carried out. The method presented acceptable trueness, precision, and linearity with LOQ of 5?μg/kg. The results obtained showed a high frequency of fungicides class pesticides in all the citrus samples examined (>95%) with the highest concentrations in the peel (4468?µg/Kg). A significant difference of concentrations was found between the layers of the citrus fruits analysed (p?<?0.05). In particular, the peel and albedo present higher pesticides significantly higher than the pulp. Our findings confirming the widespread use of these substances in citrus cultivation and suggesting the importance of pesticides analysis in all the citrus fruit layers separately, considering the different interactions between the physicochemical characteristics of the matrices and the pesticides.     

Analyzing multiple pesticides in tobacco leaf using gas chromatography with quadrupole time‐of‐flight mass spectrometry

A method combining gas chromatography with quadrupole time‐of‐flight mass spectrometry has been developed for the simultaneous analysis of multiple pesticide residues in tobacco leaf. The retention index and high accurate masses of ions from the first‐stage and the second‐stage mass spectra of each pesticide were collected for qualitation and quantification. A total of 115 pesticides were evaluated. The extract from organic tobacco leaf was used as a model matrix. The limit of detection was <10 ng/mL, and the limit of quantification was in the range of 1–20 ng/mL for 95% of the tested pesticides. The correlation coefficients were >0.9900 for all tested pesticides. At three concentrations (10, 50, and 100 ng/mL), most compounds presented satisfactory recoveries ranging from 70 to 120% and good precision <20%. Finally, three tobacco leaf samples collected from a local market were analyzed. A total of three pesticides were found, including dimethachlon, triadimenol, and flumetralin. Each pesticide was confirmed by the presence of three ions at the expected retention index and mass. In conclusion, gas chromatography with quadrupole time‐of‐flight mass spectrometry appears to be one of the most efficient tools for the analysis of pesticide residues in tobacco leaf.     

Salt‐assisted acetonitrile extraction and HPLC‐QTOF‐MS/MS detection for residues of multiple classes of pesticides in human serum samples

Detecting pesticide residues in human serum is a challenging process. In this study we developed and validated a method for the extraction and recovery of residues of multiple classes of pesticides from serum using one reagent. Salt‐assisted acetonitrile extraction and high‐performance liquid chromatography with quadrupole time of flight tandem mass spectrometry were used to quantitate 34 pesticides classified in nine groups of chemicals in human serum samples, which are frequently detected in food. The recoveries for 33 of analyzed pesticides ranged from 86 to 112% with relative standard deviations below 15%. The limits of quantitation and linearity of 31 of the pesticides were 1 µg/L and >0.990, respectively. The lower limit of quantitation has been reported in the literature particularly for multi‐classes pesticide mixtures in human serum. The salt–acetonitrile reagent was allowed to achieve good recoveries and detection limits, which could be attributed to salt altering the solvent polarity, preferentially collecting the organic phase in the solution, and promoting the extraction. The developed method was applied for two organophosphate pesticide metabolites, diethylphosphate and 3,5,6‐trichloro‐2‐pyridinol, in serum from rats that were fed a nonlethal quantity of chlorpyrifos. The concentrations of these two were 252.18 ± 15.47 and 0.63 ± 0.23 µg/L, respectively.     

母乳中多种含卤持久性有机污染物的联合检测方法

建立了母乳中多种含卤持久性有机污染物(POPs)的联合检测方法,目标化合物主要包括六溴环十二烷(HBCDs)、多溴联苯醚(PBDEs)、多氯联苯(PCBs)和有机氯农药(OCPs)等.样品的前处理采用液液萃取、凝胶渗透色谱(GPC)净化和固相萃取(SPE)等技术,目标化合物经气相色谱-质谱联用仪(GC-MS)、液相色谱-三重四极杆串联质谱联用仪(LC-MS/MS)和气相色谱-三重四极杆串联质谱联用仪(GC-MS/MS)等进行检测.样品通过GPC除去脂肪,然后经SPE柱进一步净化并进行多组分分离,极大程度地减小了生物样品中复杂基质的干扰,适合样品量相对较小的人体样本中多种超痕量POPs的分析.应用灵敏度高、选择性更好的GC-MS/MS对样品中的PCBs和OCPs等进行分析,进一步降低基质的干扰.方法经过小牛血清加标实验验证,稳定可靠.POPs的加标回收率分别为88.7％～98.8％(PBDEs), 88.5％～92.5％(HBCDs), 67.9％～82.3％(PCBs)和81.7％～116.1％(OCPs),方法检出限分别为0.13～1.8 pg/mL(PBDEs), 0.31～1.2 pg/mL(HBCDs), 0.22～1.4 pg/mL(PCBs)和0.20～1.5 pg/mL(OCPs).采用本方法对潍坊地区20例母乳样品进行分析,结果显示,潍坊市母乳中HBCDs, PBDEs, PCBs、HCHs和DDTs的中值浓度分别为2.86, 7.76, 8.84、140和503 ng/g 脂重,此浓度水平与国内其它地区人群相当.     

Determination of melamine and cyanuric acid in powdered milk using injection-port derivatization and gas chromatography–tandem mass spectrometry with furan chemical ionization

A reliable, sensitive and eco-friendly injection-port trimethylsilylated (TMS) derivatization and gas chromatography–tandem mass spectrometry (GC–MS/MS) with furan chemical ionization (furan-CI) method was developed to determine melamine and cyanuric acid in powdered milk samples. The effects of several parameters related to the TMS-derivatization process (i.e., injection-port temperature, residence time and volume of silylating agent) and of various CI agents were investigated. Addition of a solution (3 μL) of bis(trimethyl)silyltrifluoroacetamide (BSTFA) containing 1% trimethylchlorosilane (TMCS) reagent to a 20-μL extract from the powdered milk sample gave an excellent yield of the tris-TMS-derivatives of melamine and cyanuric acid at an injection-port temperature of 90 °C. Furthermore, using furan as the CI agent in conjunction with tandem mass spectrometry provided the greatest sensitivity and selectivity of detection. The limits of quantitation (LOQs) for melamine and cyanuric acid were 0.5 and 1.0 ng/g in 0.5-g of powdered milk samples, respectively. The recoveries from spiked samples – after simple ultra-sonication with 5% dimethyl sulfoxide in acetonitrile coupled with n-hexane liquid–liquid extraction – ranged from 72% to 93% with relative standard deviations of lower than or equal to 18%. In three of four real powdered milk samples, melamine was detected at concentrations ranging from 36 to 1460 ng/g; and cyanuric acid was detected in two of these samples at concentrations of 17 and 180 ng/g.