Congener group patterns of chloroparaffins in marine sediments obtained by chloride attachment chemical ionization and electron capture negative ionization

Congener group patterns of technical short chain and medium chain chloroparaffins (SCCP and MCCP) were determined by electron capture negative ionization (ECNI) and chloride attachment chemical ionization (CACI) mass spectrometry (MS). In contrast to CACI-MS, congener patterns obtained by ECNI showed always a shift to the next higher chlorinated congener and carbon chain length group. Consequently, the calculated molecular masses and chlorine contents were higher for ECNI (factor 1.10+/-0.03 and 1.09+/-0.03, respectively). ECNI/CACI ratios in sediment samples from the North and Baltic Sea were also slightly higher. However, a more pronounced shift of the congener pattern for a given carbon chain length to congeners with 2-3 more chlorine atoms was observed. SCCP and MCCP concentrations obtained by ECNI-MS were in the range of 8-63ngg(-1) (North Sea) and 22-149ngg(-1) dry weight (Baltic Sea). MCCP levels were highest in all samples (MCCP/SCCP factor 1.1-3.2).     

Synthesis, isolation and purification of C10-C13 polychloro-n-alkanes for use as standards in environmental analysis

Short chain (C10-C13) polychloro-n-alkanes (sPCAs) mixtures were synthesized by refluxing pure n-alkane (> 99%) with sulfuryl chloride (SO2Cl2) in the presence of UV-light (550 W). The free radical initiated reactions produced analogs containing approximately 4-9 chlorine atoms on each carbon chain. Purification of reaction products was achieved by adsorption chromatography on Florisil. The products were characterized by high-resolution gas chromatography/mass spectrometry (HRGC/MS) operated in the electron capture negative ionization (ECNI) and in electron ionization (EI) modes. Individual standards can now be combined to create standards whose profiles resemble that of environmental samples. Quantification of a known amount of the newly synthesized sPCAs mixture, using an industrial formulation as an external standard, resulted in an overestimation (approximately 28%) in its true value.     

Congener-specific analysis of toxaphene in eggs of seabirds from Germany by HRGC-NCI-MS using a carborane-siloxane copolymer phase (HT-8)

A method for the congener-specific analysis of toxaphene in eggs of seabirds from a monitoring program from the northern part of Germany was carried out. The method was optimized in most steps of the procedure: injection temperature, HRGC with an HT-8 column, ion source temperature and the MS detection mode NCI/SIM measuring the isotope clusters of [M] , [M-Cl]-, [M-HCl]- and [M-2Cl]-. The suitability of 1,4-exo, 7,8,9,10,10-heptachloro-5-methoxytricyclo [5,2,1,0(2,6)]dec-3,8-diene as internal standard was demonstrated. 14 toxaphenes with Parlar numbers and more than 60 unknown toxaphenes could be identified. Spatial and temporal trends of toxaphene contamination are presented by using the Parlar 22 components standard for quantification.     

First study of congener group patterns and concentrations of short- and medium-chain chlorinated paraffins in fish from the North and Baltic Sea

This study presents the first investigation of concentrations and congener group patterns of short- (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in fish from the North and Baltic Sea. North Sea dab, cod and flounder were studied. High resolution gas chromatography (HRGC) coupled to low resolution mass spectrometry (LRMS) in the electron capture negative ionization mode (ECNI) was employed. Good linearity (R2>0.993, 7 measuring points) was achieved between 1 and 100 ng/g of CP mixtures for SCCPs and MCCPs. The limits of detection were 0.5-1 ng/microl of CP mixture for the major congener groups of SCCPs and MCCPs. A clean-up comprising fat extraction, adsorption chromatography on silicagel impregnated with concentrated sulphuric acid and adsorption chromatography on Florisil was employed to avoid interferences from other polychlorinated compounds. Recoveries of CPs in spiked samples ranged between 80% and 100%. Accuracy was controlled with spiked samples and deviated not more than 10% from the expected values. Quantification was performed with standards of an average chlorine content as close as possible to that of the samples (SCCPs: 59-62%, MCCPs: 53-58%). SCCP concentrations ranged between 19 and 286 ng/g liver wet weight (ww), MCCP concentrations were comparable with a range of 25-260 ng/gww. Congener group patterns were also determined and discussed. In samples from the Baltic Sea the SCCP congener pattern was similar to that of commercial SCCP mixtures or C13 congeners were most abundant. In samples from the North Sea a higher relative abundance of C10 congeners was observed.     

Comparing electron ionization high-resolution and electron capture low-resolution mass spectrometric determination of polybrominated diphenyl ethers in plasma, serum and milk

Gas chromatography coupled to low-resolution mass spectrometry with electron capture negative ionization as detection mode (GC-LRMS (ECNI)) has been compared to gas chromatography coupled to high-resolution mass spectrometry using electron ionization as detection mode (GC-HRMS (EI)) for determination of polybrominated diphenyl ethers (PBDEs) in biological samples. Extracts of 5.0 g plasma, serum and milk samples were analyzed using both methods. The GC-LRMS (ECNI) and GC-HRMS (EI) systems were found to be equally well suited for determination of PBDEs in the biological samples, as well as in standard solutions, with respect to response, detection limits and repeatability at the pg-level. The estimated limits of detection (LOD) in milk extracts ranged from 0.3-0.6 pg PBDE/g milk and 0.4-0.7 pg PBDE/g milk, for the GC-LRMS (ECNI) and GC-HRMS (EI) systems, respectively. The method repeatability including sample preparation was in the range 4.7-8.4% and 0.6-10% relative standard deviation (RSD) for the GC-LRMS (ECNI) and GC-HRMS (EI) systems, respectively.     

Analysis of polychlorinated naphthalenes in environmental samples

A method for the analysis of polychlorinated naphthalenes (PCN) has been developed. It is based on a simple clean-up procedure using activated carbon and a mass fragmentographic analysis using the negative ions formed during chemical ionization (NCI). Unlike the technical PCN products we have analyzed, a few isomerides containing four to six chlorine atoms dominate the PCN pattern in the environmental samples. The levels found in samples of biota from fresh water and marine environments in Sweden were between 3 and 62 ng PCN per gram lipid.     

Experimental octanol/water partition coefficients of chlorinated paraffins

Octanol/water partition coefficients (K_OW) of chlorinated paraffins (CPs) from a commercial mixture (‘Cereclor 60L’) were determined using a “slow-stirring” method. Log K_OW values for the different congener groups ranged from 5.85 to 7.14. Equilibrium was reached within a few days, and K_OW values were the same at two CP-concentrations. A clear relationship is found between the total number of chlorine and carbon atoms and log K_OW for the CP-congener groups and a series of smaller chlorinated alkanes from the literature.     

Structure elucidation of four possible biogenic organohalogens using isotope exchange mass spectrometry

The molecular structures of four unknown bioaccumulating halogenated compounds, C10H6N2Br3Cl3, C10H6N2Br4Cl2, C10H6N2Br5Cl, and C10H6N2Br6 were characterized using isotope exchange positive chemical ionization (IE-PCI) mass spectrometry (MS) and identified by comparison to synthesized standards. NH3 and ND3 were used as reagent gases for the IE-PCI-MS experiment. The shift in mass of the quasimolecular ion between the NH3 and ND3 PCI obtained spectra indicated the number of exchangeable hydrogens attached to the two nitrogen atoms in C10H6N2Br4Cl2, and thus the type of amines present (primary, secondary, or tertiary). 19 compounds (13 amines of varying degree of substitution; six containing no nitrogen) were used as reference compounds and controls in the experiment to validate the IE-PCI technique. The results of the IE-PCI-MS indicated the presence of two tertiary amine functional groups. The molecular structures of the four hexahalogenated compounds were then proposed to be 1,1'-dimethyl-3,3',4,-tribromo-4',5,5'-trichloro-2,2'-bipyrrole, 1,1'-dimethyl-3,3',4,4'-tetrabromo-5,5'-dichloro-2,2'-bipyrrole, 1,1'-dimethyl-3,3',4,4',5-pentabromo-5'-chloro-2,2'-bipyrrole, and 1,1'-dimethyl-3,3',4,4',5,5'-hexabromo-2,2'-bipyrrole and subsequently synthesized. Comparison of retention times and electron capture negative ionization (ECNI) full scans on various gas chromatography (GC) columns between the synthesized bipyrroles and the corresponding unknown compounds in biota indicated that three of the unknown compounds--possible marine natural products--were the proposed halogenated dimethyl bipyrroles. The placement of the halogen atoms on the fourth compound, C10H6N2Br3Cl3 could not be unequivocally determined since the synthesized standard could not be fully characterized.     

Studies on the coupling product between oxidation products derived from pentachlorophenol and cyclodextrins

The coupling products (CPs), which were formed via the peroxosulfate catalyzed oxidation of pentachlorophenol (PCP) with iron(III)-tetrakis(sulfonatophenyl)porphyrin (Fe(III)-TPPS) in the presence of hydroxypropyl-beta -cyclodextrin (HP-beta -CD) or HP-gamma -CD, were separated by ultrafiltration from the reaction mixture. When the percentages of chlorine species in the reaction mixture were calculated from the concentrations of organic chlorine in the reaction mixture and CPs, 10-25% of chlorine species in the reaction mixture was organic chlorine that was incorporated into CDs. Analyses of the CPs by pyrolysis-GC/MS (Py-GC/MS) and 13C NMR showed that the PCP-derived products were covalently incorporated into the CDs. To evaluate the acute toxicity of the CPs, a Microtox test was examined. Toxicities of the CPs were reduced slightly, compared to the controls (PCP alone and PCP + reaction blanks). In the reaction blanks, mesaconic acid (MA) moieties were detected as a result of the oxidation of CDs in the absence of PCP. Thus, factors in the toxicities, detected in the CPs, can be attributed to the oxidation products derived from CDs, such as MA, as well as the PCP-derived products incorporated into the CDs.     

Altitude profiles of total chlorinated paraffins in humus and spruce needles from the Alps (MONARPOP)

Chlorinated paraffins (CPs) are toxic, bioaccumulative, persistent, and ubiquitously present in the environment. CPs were analyzed in humus and needle samples, which were taken within the Monitoring Network in the Alpine Region for Persistent and other Organic Pollutants (MONARPOP) at sampling sites of 7 different altitude profiles in the Alps. Gas chromatography combined with electron ionization tandem mass spectrometry (EI-MS/MS) was used for the determination of total CPs (sum of short, medium and long chain CPs). CPs were found in all samples; the concentrations varied between 7 and 199 ng g⁻¹ dry weight (dw) and within 26 and 460 ng g⁻¹ dw in humus and needle samples, respectively. A clear vertical tendency within the individual altitude profiles could not be ascertained. Within all altitude profiles, elevated concentrations were observed in humus samples taken between 700 and 900 m and between 1300 and 1500 m. In the needle samples no similar correlation could be observed due to higher variation of the data.     

Studies on the Coupling Product between Oxidation Products Derived from Pentachlorophenol and Cyclodextrins

The coupling products (CPs), which were formed via the peroxosulfate catalyzed oxidation of pentachlorophenol (PCP) with iron(III)-tetrakis(sulfonatophenyl)porphyrin (Fe(III)-TPPS) in the presence of hydroxypropyl-β -cyclodextrin (HP-β -CD) or HP-γ -CD, were separated by ultrafiltration from the reaction mixture. When the percentages of chlorine species in the reaction mixture were calculated from the concentrations of organic chlorine in the reaction mixture and CPs, 10–25% of chlorine species in the reaction mixture was organic chlorine that was incorporated into CDs. Analyses of the CPs by pyrolysis-GC/MS (Py-GC/MS) and ¹³C NMR showed that the PCP-derived products were covalently incorporated into the CDs. To evaluate the acute toxicity of the CPs, a Microtox® test was examined. Toxicities of the CPs were reduced slightly, compared to the controls (PCP alone and PCP + reaction blanks). In the reaction blanks, mesaconic acid (MA) moieties were detected as a result of the oxidation of CDs in the absence of PCP. Thus, factors in the toxicities, detected in the CPs, can be attributed to the oxidation products derived from CDs, such as MA, as well as the PCP-derived products incorporated into the CDs.     

纳米Pd／Fe双金属颗粒对单氯酚及二氯酚的还原脱氯

采用改进液相化学还原法制备纳米Pd／Fe双金属颗粒，研究其钯化率为0．045％和0．135％的条件下分别对3种单氯酚（2-CP、3-CP和4-CP）和3种二氯酚（2，3-DCP、2，4-DCP和2，6-DCP）的脱氯反应。结果表明，合成的纳米Pd／Fe颗粒分散性良好，粒径分布介于25～40nm。纳米Pd／Fe双金属颗粒对单氯酚及二氯酚具有良好的去除效果，3种单氯酚和3种二氯酚的脱氯难易程度分别为2-CP〉4-CP〉3-CP和2，6-DCP〉2，4-DCP〉2，3-DCP，脱氯反应均符合拟一级反应动力学方程。通过还原脱氯实验揭示了分子中氯原子的化学环境对还原脱氯过程具有明显影响。     

Contribution of free radicals to chlorophenols decomposition by several advanced oxidation processes

The chemical decomposition of aqueous solutions of various chlorophenols (4-chlorophenol (4-CP), 2,4-dichlorophenol (2-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP)), which are environmental priority pollutants, is studied by means of single oxidants (hydrogen peroxide, UV radiation, Fenton's reagent and ozone at pH 2 and 9), and by the Advanced Oxidation Processes (AOPs) constituted by combinations of these oxidants (UV/H2O2 UV/Fenton's reagent and O3/UV). For all these reactions the degradation rates are evaluated by determining their first-order rate constants and the half-life times. Ozone is more reactive with higher substituted CPs while OH* radicals react faster with those chlorophenols having lower number of chlorine atoms. The improvement in the decomposition levels reached by the combined processes, due to the generation of the very reactive hydroxyl radicals. in relation to the single oxidants is clearly demonstrated and evaluated by kinetic modeling.     

Chlorinated and polycyclic aromatic hydrocarbons in riverine and estuarine sediments from Pearl River Delta, China

Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the estuarine sediment samples are in the range 6-1658 ng/g, while concentrations of PCBs are in the range 10-339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine sediment samples, whereas the PAH concentration ranges from 323 to 14,812 ng/g in the sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.     

Development of a comprehensive analytical method for the determination of chlorinated paraffins in spruce needles applied in passive air sampling

Conifer needles are used for the monitoring of atmospheric persistent organic pollutants. The objective of the present study was to develop a method for the detection of airborne chlorinated paraffins (CPs) using spruce needles as a passive sampler. The method is based on liquid extraction of the cuticular wax layer followed by chromatographic fractionation and detection of CPs using two different GCMS techniques. Total CP concentrations (sum of short (SCCP), medium (MCCP) and long chain CPs (LCCP)) were determined by EI-MS/MS. SCCP and MCCP levels as well as congener group patterns (n-alkane chain length, chlorine content) could be evaluated using ECNI-LRMS. For the first time, data on environmental airborne CPs on spruce needles taken within the Monitoring Network in the Alpine Region for Persistent and other Organic Pollutants (MONARPOP) are presented providing evidence that spruce needles are a suitable passive sampling system for the monitoring of atmospheric CPs.     

Plant metabolites of polychlorinated biphenyls in hairy root culture of black nightshade Solanum nigrum SNC-9O

The present study is intended to determine metabolites of 12 dichlorinated, seven trichlorinated, five tetrachlorinated and one pentachlorinated PCB congener transformed by black nightshade (Solanum nigrum) hairy root culture SNC-9O. Free hydroxylated PCB metabolites were identified based on the mass spectra characteristics after gas chromatography separation. The number of metabolites decreases with an increasing number of chlorine atoms per molecule of PCB. Dichlorinated PCBs lead always to at least two metabolites. In the case of PCB 9 some metabolites could be identified by comparing their RF values due to available standards. The 2',5'-dichloro-2-biphenylol, 2',5'-dichloro-3-biphenylol and 2',5'-dichloro-4-biphenylol, present as the main metabolite, were found in biomass of SNC-9O hairy root culture. Two monochlorinated biphenylols were found in biomass of SNC-9O degrading PCB 9 congener. It was the only case when metabolites with decreased number of chlorine atoms compared to parent PCB were found. Trichlorinated PCBs mostly lead to a lower number of metabolites but tetrachlorinated and pentachlorinated PCBs mostly did not give any metabolites. In the media, only traces of metabolites were found in sporadic cases, so exudation of unbound biphenylols from the cells is not expected.     

Mechanochemical removal of organo-chlorinated compounds by inorganic components of soil

The purpose of this work is to evaluate the catalytic efficiency of two metal oxides, ferrihydrite and birnessite and of a ferruginous smectite, towards organic molecules such as 4-chloroaniline (4-CA), pentachlorophenol (PCP), and five polychlorinated biphenyls (PCBs) characterised by different number and position of chlorine atoms. Mechanochemical dry contacts with light grinding between catalytic surfaces and pollutants have been carried out.

The efficiency of the mechanochemical removal was compared with batch experiments for the soluble compounds (PCP and 4-CA). The removal of 4-CA and PCP by the mechanochemical procedure resulted more effective than by batch contact in the presence of birnessite and ferrihydrite, particularly at higher pH (100% removal of 4-CA by birnessite in 30 min at pH 8.6 after the mechanochemical contact compared to 20% removal using the batch interaction at the same pH).

The mechanochemical contact of PCBs and birnessite produced a removal of pollutant that was a function of the number of chlorine atoms (complete removal of 2,2^′-dichlorobiphenyl in 10 days and a removal of 30% and 20% of 2^′,3,4-trichlorobiphenyl and 3,3^′,4,4^′-tetrachlorobiphenyl, respectively in 90 days) and of the position of chlorine atoms about the biphenyl rings (100% of 2,2^′-dichlorobiphenyl in 10 days, 84% of 3,3^′-dichlorobiphenyl in 15 days and 40% of 4,4^′-dichlorobiphenyl in 27 days).