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Analytical and Bioanalytical Chemistry (v.359, #3)
Discovery of utmost inner time precision in chromatography by R. E. Kaiser (pp. 208-212).
An up to now unknown high “inner time precision” in isocratic gas chromatography (GC) and high pressure column liquid chromatography (HPLC) has been realized using quartz clock driven A/D converters and special statistically evaluating integration software. This millisecond level inner time precision is detectable by two very linear data correlations: a) the log of adjusted retention times (log(t R′)) versus the molecular weight of separated members of homologues and b) the peak width at half height versus correct k-values of the homologues. The inner time precision at the millisecond level is not lost by slight errors (up to seconds) in the starting times of GC or HPLC determinations. The correlation coefficient of the two linear data correlations allows a thorough analysis of instrument quality. The highly linear correlation of peak width and k in a wide range of mobile phase speeds is in disagreement with theoretical models of chromatography. Especially the rule of variance additivity is not valid in isocratic elution chromatography.
The potential of gas chromatography with microwave-induced plasma atomic emission detection (GC-MIP-AED) as a complementary analytical technique in environmental screening analysis of aqueous samples by H. Frischenschlager; C. Mittermayr; M. Peck; E. Rosenberg; M. Grasserbauer (pp. 213-221).
With GC-MIP-AED as a complementary analytical technique to GC-MS, the reliable identification of many organic pollutants in water samples of the Nitra river has been made possible due to the additional information on the elemental composition of organic pollutants it provides. Some compounds, which have been identified by GC-MS in the scan mode after a MS-library search, can be confirmed by their element responses. Even where the identification of substances cannot be confirmed by their empirical formulas calculated by GC-MIP-AED due to insufficient peak intensities, integration problems or chromatographic interferences, it can be facilitated by the presence of one or more heteroatoms. Quantitative data of selected organic pollutants from GC-MIP-AED screening analysis after compound independent calibration can be obtained more easily than, and in good agreement with, quantitative results provided by target analysis (e.g. GC-MS in the SIM-mode). New self-developed macros are helpful tools for acquiring information on the elemental composition and concentration of organic pollutants analyzed by GC-MIP-AED.
Certification of the contents of five polychlorodibenzo-p-dioxins and six polychlorodibenzo furans in milk powder by L. G. M. T. Tuinstra; J. R. Startin; E. A. Maier; G. N. Kramer (pp. 222-229).
Preparation, homogeneity and stability studies of a natural milk powder material and subsequent certification of the mass fraction of five polychlorodi-benzo-p-dioxins (D48, D54, D66, D67, D70) and six polychlorodibenzo furans (F83, F94, F114, F118, F121, F130) are described. The material, CRM 607, is intended for use in the method validation and quality control of the complete analytical procedure for congener-specific determination of dioxins in milk powder and similar dairy products and was certified in an interlaboratory study for: 2,3,7,8-TCDD, 0.25 ng/kg; 1,2,3,7,8-PeCDD, 0.79 ng/kg; 1,2,3,4,7,8-HxCDD 0.42 ng/kg; 1,2,3,6,7,8-HxCDD, 0.98 ng/kg; 1,2,3,7,8,9-HxCDD, 0.34 ng/kg; 2,3,7,8-TCDF, 0.05 ng/kg; 1,2,3, 7,8-PeCDF, 0.054 ng/kg; 2,3,4,7,8-PeCDF, 1.81 ng/kg; 1,2,3,4,7, 8-HxCDF, 0.94 ng/kg; 1,2,3,6,7,8-HxCDF, 1.01 ng/kg and 2,3,4,6,7,8-HxCDF, 1.07 ng/kg. An indicative (non-certified) value was assigned to the mass fraction of the hepta- and octachlorinated congeners D73, D75, F131, F134, F135 and the HxCDF F124.
Multi-element characterization of high-purity titanium dioxide by neutron activation analysis by D. Wildhagen; V. Krivan (pp. 230-238).
A radiochemical neutron activation analysis method for the determination of 34 elements in titanium dioxide has been developed. For the assay of indicator radionuclides with short and with long half-lives, the radiochemical separation was performed by anion exchange on a Dowex 1 × 8 column and by combination of cation and anion exchange on a Dowex 50W × 8 and a Dowex 1 × 8 column from HF- and HF/NH4F-medium, respectively. With both separation modes, a selective removal of the matrix-produced radionuclides 46Sc, 47Sc and 48Sc was achieved. A selective extraction of copper with dithizone from 15 mol/L HF enabled counting the intensive but unspecific 511-keV rays of 64Cu for the determination of Cu. The limits of detection achieved were between 0.004 ng/g for Sm and 0.8 μg/g for Sn (via 125Sb). The elements La, Mn and Th were determined by instrumental neutron activation analysis only. These techniques were applied to the analysis of two titanium dioxide samples of different purity grade. The results and limits of detection are compared with those of other methods.
Screening-method for organotins by elimination of the inorganic tin matrix using a coupling of hydride generation (HG) and transversely heated graphite atomizer-atomic absorption spectrometry (THGA-AAS) by H. G. Riepe; D. Erber; J. Bettmer; K. Cammann (pp. 239-243).
A selective detection method for organotin compounds by elimination of the inorganic tin matrix has been worked out using a coupling of the hydride generation technique (HG) with transversely heated graphite atomizer-atomic absorption spectrometry (THGA-AAS). The suppression of the inorganic tin matrix bases on the utilization of kinetic interferences during the hydride generation step avoiding expensive chromatographic separation techniques. For the different organotins this method delivers detection limits in the range 0.9–1.2 μg/L using a 500 μL sample loop. In comparison with the fully automated determination system this modification represents an efficient screening-method for the determination of organotin in environmental samples allowing fast and inexpensive monitoring.
Contamination by butyltin compounds in harbour porpoise (Phocoena phocoena) from the Black Sea by Bathini Madhusree; S. Tanabe; Ayaka Amaha Öztürk; Ryo Tatsukawa; Nobuyuki Miyazaki; Emin Özdamar; Orhan Aral; Osman Samsun; Bayram Öztürk (pp. 244-248).
Concentrations of butyltin compounds (BTs) were determined in harbour porpoise (Phocoena phocoena) collected from the Turkish coastal waters of the Black Sea. Total butyltin compounds (∑ BTs) in the liver were in the range of 89–219 ng/g on a wet weight basis. The dibutyltin (DBT) residues were higher than those of tributyltin (TBT), suggesting the degradation of TBT to DBT in the liver and the metabolic capacity comparable to other marine mammals. Any sex difference and age-dependent accumulation of BTs residues were not found in harbour porpoises, but residue levels increased until maturity and then remained constant. When compared with other marine mammals, the present results indicate that the Black Sea is also contaminated with butyltin compounds, but to a lesser degree than coastal waters of developed nations. The biomagnification factor in harbour porpoises was 0.8, which was comparable with pinnipeds and lower than cetaceans.
Liquid chromatographic isolation of coplanar PCB congeners on an activated carbon stationary phase by Astrid Trost; W. Kleiböhmer; Karl Cammann (pp. 249-253).
A rapid and uncomplicated method for the fractionation of PCBs leading to an isolation of the highly toxic non-ortho substituted PCBs is described. The liquid chromatographic separation was achieved on a stationary phase consisting of activated carbon and Celite 545. Using eluents with different polarity, isolation of the non-ortho substituted PCBs in a single fraction was achieved. The fractions were analysed by GC/MS. The method was tested by the determination of non-ortho substituted PCBs in technical mixtures (Aroclor 1254 and Aroclor 1242). The results were compared with those obtained by using an HPLC fractionation on a porous graphitic carbon column. Finally, the micro-column fractionation was used for the determination of non-ortho substituted PCBs in native soil samples.
Levels and patterns of polychlorinated biphenyls in water collected from the San Francisco Bay and Estuary, 1993–95 by W. M. Jarman; Glenn W. Johnson; Corinne E. Bacon; Jay A. Davis; Robert W. Risebrough; Robert Ramer (pp. 254-260).
Levels of polychlorinated biphenyls (PCBs) were measured in water (particulate and dissolved fractions) from various locations in the San Francisco Estuary over the years 1993–1995 during six cruises. Geometric mean levels of ΣPCBs (sum of 58 congeners) in the combined dissolved and particulate fractions for the six cruises ranged from 340 ng/L to 1600 ng/L. Comparing this data to previous data from 1975 and 1980 does not reveal any significant temporal trends. The partitioning of PCBs into the dissolved/particulate fraction were correlated with total suspended solids. Using the novel chemometric technique of polytopic vector analysis (PVA) on the data from cruise 8 (April 1995), five separate PCB congener fingerprints were identified in the data. Fingerprint 1 (or end-member 1) represents a slightly degraded source of Aroclor® 1260 in the northern part of the South Bay; the end-member (EM) 2 fingerprint is related to a predominantly Aroclor® 1260 source that has been moderately-severely degraded present in the highest proportions in the Pacific Ocean sample; EM-3 is interpreted as a slightly degraded Aroclor® 1242:1254:1260 mixture in southern San Pablo Bay; end-member 4 is interpreted as a moderately degraded source of multiple Aroclors® and is present in the river samples; EM-5 is interpreted as a slightly degraded Aroclor® 1254/1260 mixture present in northern San Pablo Bay and the South Bay.
Separation of polychlorinated dibenzothiophenes from polychlorinated dibenzodioxins and -furans by Klaus Sielex; J. T. Andersson (pp. 261-266).
Polychlorinated dibenzothiophenes (PCDT) have recently been identified in a series of environmental samples. Since their masses are very close to those of the polychlorinated dibenzodioxins (PCDD), low resolution mass selective detection cannot be used to distinguish between these two classes of compounds. A method is presented which may allow this, involving the oxidation of the PCDTs to the corresponding sulfones which have a higher mass than the PCDDs. If needed, the PCDTO2s can easily be separated from the PCDDs and the polychlorinated dibenzofurans (PCDFs) by simple chromatographic techniques. The PCDDs/Fs are apparently stable under the oxidative conditions so that now a determination of PCDDs and PCDFs becomes possible without interference from PCDTs.
Comparison of liquid chromatography-mass spectrometry interfaces for the analysis of polar metabolites of benz[a]pyrene by Robert Koeber; R. Niessner; Josep Maria Bayona (pp. 267-273).
The performance of two liquid chromatography-mass spectrometry (LC/MS) interfacing techniques, thermospray (TSP) and atmospheric pressure chemical ionization (APCI), for the analysis of benzo[a]pyrene (BaP) metabolites (hydroxy, epoxy and quinone derivatives) was compared. Interface and detection parameters such as source temperature, eluent composition or flow rate were optimized using negative ion mode. In TSP, the main ions are mostly [M]-, [M−H2O]- or [M+CH3COO]-, whereas APCI gives mainly the [M]- and [M−H]- ions. Quantification was carried out by flow injection. Calibration graphs were linear in the range of 10 ng to 1000 ng in TSP and 0.1 ng to 10 ng in APCI. Detection limits were in the range of 1 ng to 20 ng in TSP and 0.002 ng to 0.2 ng in APCI. The presence of BaP-1,6-dione, BaP-3,6-dione, and BaP-6,12-dione was confirmed in environmental samples of air particulate matter.
Ozonation of pyrene and benzo[a]pyrene in silica and soil –14C-mass balances and chemical analysis of oxidation products as a first step to ecotoxicological evaluation by M. Eberius; Anne Berns; Ingolf Schuphan (pp. 274-279).
Ozonation of polycyclic aromatic hydrocarbons (PAHs) in soil is a process that can be used for in-situ soil remediation or in combination with bioremediation techniques. First steps to a comprehensive ecotoxicological evaluation of this method is done by ozonation of radioactively labeled (14C) pyrene and benzo[a]pyrene in a silty soil (LUFA 2.2) under mass-balancing conditions and GC-MS analysis of aromatic ozonation products. 14C-Mass-balances for pyrene and benzo[a]pyrene (b[a]p) in soil showed that, apart from 14CO2 formation, considerable percentages of both PAHs are oxidized to water soluble substances (20–30%) or to non-extractable or bound residues (10% for pyrene, 30% for b[a]p). TLC and GC-MS analysis of ozonation products extractable from artificially contaminated silica and soil by organic solvents revealed a large number of aromatic substances. PAH-quinones and ten ring fission products with formyl- and carboxy-groups of both pyrene and b[a]p could be identified.
Polycyclic aromatic hydrocarbons in Ya-Er Lake (Hubei, China): sources and distribution by G. S. Chen; K.-W. Schramm; C. Klimm; Y. Xu; Y. Y. Zhang; A. Kettrup (pp. 280-284).
Sources and distribution of polycyclic aromatic hydrocarbons (PAH) in the Ya-Er Lake area (Hubei, China) sediment cores of 3 ponds in the shallow Ya-Er Lake were investigated for 16 PAH. Analytical procedure included extraction by ultrasonication, clean-up by gel-permeation and quantification by HPLC with fluorescence detection. The total PAH amount in sediment samples of the Ya-Er Lake ranged from 68 to 2242 μg/kg. Concentrations decreased from pond 1 to pond 3 and from upper to lower sediment layers. In addition a soil sample from Ya-Er Lake area showed a total PAH amount of 58 μg/kg. The PAH pattern in lower sediment layers were similar to that of the soil sample which indicates an atmospheric deposition into the sediments prior to 1970 only. The PAH profile of upper sediment samples, which differs completely from that of lower layers, may be explained by a gradually increasing input of mixed combustion and raw fuel sources since 1970. Therefore the origin of increased PAH contamination in Ya-Er Lake during the last 3 decades has been probably an industrial waste effluent in pond 1.
Trace analysis of epichlorohydrin in water samples by H.-J. Neu; R. Sprenger (pp. 285-287).
According to a recent proposal of a new council directive of the Commission of the European Community concerning the quality of water intended for human consumption, the maximum concentration of epichlorohydrin allowed in potable water is intended to be limited to 0.5 μg/L. To our knowledge no practical analytical technique for routine analysis purposes of aqueous samples is available at present. In this paper an analytical method is described using solid phase extraction (SPE) for the enrichment of epichlorohydrin from water samples with subsequent determination by gas-liquid chromatography with electron capture detection. Quantitative recovery was achieved. Using a sample volume of 100 mL a detection limit of 0.1 μg/L can be reached. The method has successfully been applied to the analysis of epichlorohydrin in tap water, surface water and waste water.
Particle beam LC/MS screening of polar compounds of contaminated ground water samples from a former gas plant by B. Edler; C. Zwiener; F. H. Frimmel (pp. 288-292).
A commercial particle beam interface coupled to a single quadrupole mass spectrometer has been used for a nontarget screening of highly contaminated water samples from a former gas plant. A liquid chromatographic system has been used to separate hydrophilic compounds with a high percentage water gradient without any loss of efficiency in the MS interface. The ground water showed a high pollution burden in the total ion current chromatogram. Full scan EI mass spectra have been obtained for identification of unknown compounds which could be assigned to oxidation products of heterocyclic aromatic compounds, some known constituents of coal tar. The identification of 6(5H)-phenanthridinone has been confirmed by comparison with a corresponding standard. The difficulties of an unequivocal identification of isoquinolinone and methyl derivatives of quinolinone based on their EI mass spectra are discussed.
Improvement of GC-MS analysis of organochlorine pesticides in sediments by use of a computer-optimized temperature program by H. Pichler; O. Gans; R. Krska; M. Grasserbauer (pp. 293-297).
A simulation and optimization software program (Pro ezGC® by Analytical Innovations, Inc., Kettering, OH, USA) for GC temperature programs was applied to the analysis of organochlorine pesticides in sediments. By means of this software, the run time of a conventional temperature program derived from trial and error experiments could be reduced to less than a third, achieving at the same time an increased separation efficiency. Finally, 17 organochlorine pesticides could be baseline-resolved on a capillary column in less than 12 min. In addition, a two-fold sensitivity enhancement was achieved.
Biogenic volatile organoiodine and organobromine hydrocarbons in the Atlantic Ocean from 42°N to 72°S by C. Schall; K. G. Heumann; G. O. Kirst (pp. 298-305).
During the cruise ANT X/1 and 2 of the research vessel Polarstern from November 1991 to March 1992, 39 surface water samples of the Atlantic Ocean from 42°N to 72.5°S were collected and analysed for their concentration of volatile iodinated and brominated hydrocarbons. The concentration of chlorophyll-a was used as an indicator for phytoplankton, which is one of the main producers of iodinated and brominated compounds in the ocean. For determination of chlorophyll-a, fluorescence spectroscopy was applied, whereas the measurement of halogenated volatile hydrocarbons was carried out by a purge and trap system with subsequent gas chromatographic separation and detection by an electron capture detector. With this technique the brominated substances CHBr3, CH2Br2, CHBr2Cl and CHBrCl2 have been detected in the range of <0.03 ng/L to 15 ng/L. For these volatile bromomethanes a distinct concentration profile was found. CHBr3 was always found to be the substance with the highest concentration followed by CH2Br2, CHBr2Cl and CHBrCl2. It could also be shown that in addition to CH3I, which for a long time was believed to be the only volatile iodinated substance in the marine environment, other iodinated substances like CH2ClI, CH2I2 and CH3CH2CH2I exist in the range of <0.01 ng/L to 2.2 ng/L in surface water of the Atlantic Ocean.Although it is improbable that chlorophyll-a is directly involved in the marine production of halogenated hydrocarbons, it was found that it could be used as an indicator for the biogenic formation of brominated compounds, whereas the correlation between chlorophyll-a and the iodinated substances was not of the same quality. The positive correlation between bromoform and dibromomethane proves the same biogenic origin and mechanism of formation, which could not be found for the different iodinated compounds.