Peter Sundin

Enrichment of chlorinated fatty acids in fish lipids prior to analysis by capillary gas chromatography with electrolytic conductivity detection and mass spectrometry

Abstract Chlorinated carboxylic acids of fatty acid character have been shown to account for up to 90% of the extractable, organically bound chlorine (EOCl) in fish. To facilitate the detection of chlorinated fatty acid methyl esters (FAMEs) released from fish lipids, an enrichment was performed by removing the polyunsaturated FAMEs and saturated, straightchain FAMEs through their complexation with silver ions and urea, respectively. The resulting about 30-fold increase in the concentration of chlorinated FAMEs allowed for their analysis, by gas chromatography (GC) with halogen-selective electrolytic conductivity detection, in lipids containing only 30 ppm (m/m) of EOCl. Following additional purification by thin-layer chromatography, methyl esters of dichlorotetradecanoic, dichlorohexadecanoic and dichlorooctadecanoic acids were indicated by GC-ammonia positive ion chemical ionisation mass spectrometry in a fish sample containing 1200 ppm (m/m) of EOCl.

Supported Liquid Membranes for the Extraction of Phenolic Acids from Circulating Nutrient Solutions

Abstract A supported liquid membrane system has been developed for the extraction of phenolic acids for circulating nutrient solutions for tomato culture. A porous PTFE membrane is impregnated with an organic solvent, which thus forms a barrier between two aqueous phases. The analytes are extracted from an aqueous donor solution into the hydrophobic membrane and then back extracted into a second aqueous solution, the acceptor, were the analytes are irreversible trapped. By pumping the donor and keeping the acceptor stagnant, an enrichment of analytes in the acceptor is achieved. The final determination is performed with liquid chromatography and UV-detection utilised with a PRP-1 packed precolumn replacing the injection loop. The stability of five phenolic acids (p-hydroxy benzoic acid, vanillic acid, caffeic acid, p-coumaric acid and ferulic acid) in the nutrient solutions during various storage conditions is reported. High flow rates (up to 6.5 mL/min) are for the first time reported with the SLM-techni...

Gas Chromatographic and Mass Spectrometric Identification of Tetrachloroalkanoic and Dichloroalkenoic Acids in Eel Lipids

Chlorinated fatty acid methyl esters, transesterified from the lipids of eel (Anguilla anguilla ; obtained from the receiving waters of a chlorine bleaching pulp mill), were studied by gas chromatography (GC) using electrolytic conductivity detection and mass spectrometry (MS) with electron impact and ammonia positive-ion chemical ionization. GC retention indices and column difference values in combination with GC/MS demonstrated the presence of isomers of methyl dichlorotetradecenoate, methyl dichlorohexadecenoate, methyl dichlorooctadecenoate and methyl tetrachlorotetradecanoate. Isomers of methyl threo, threo-tetrachlorooctadecanoate were identified by co-injection of the eel sample and synthesized reference compounds. The results were confirmed by ammonia positive-ion chemical ionization high-resolution selective-ion monitoring of the ammonium adduct molecular ions.

HALOGENATED FATTY ACIDS : I. FORMATION AND OCCURRENCE IN LIPIDS

Abstract Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also, chlorinated lipids have been found in meat exposed to hypochlorite disinfected water, and in chlorine-treated flour and in products made from such flour. Following exposure to chlorine bleached pulp mill effluents, aquatic organisms may have elevated concentrations of chlorinated fatty acids in their lipids. However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their determination.

Interactive effects of lettuce (Lactuca sativa L.), irradiance, and ferulic acid in axenic, hydroponic culture

Ferulic acid (FA) is released by living roots and by decaying plant material and is involved in chemical interactions between plants. Effects of FA on plant growth and root development of lettuce (Lactuca sativa L. cv. Grand Rapids) cultivated in axenic nutrient solution were studied in two factorial experiments. Root and shoot growth was impeded when 200 μM trans-FA was added to the nutrient solution and the light intensity was in the range of 250–380 μmol m-2 s-1. Root growth showed a stronger response to FA than did shoot growth. At 200 μM, FA strongly inhibited root hair formation and reduced mean lengths of primary, secondary and tertiary roots, but stimulated primary and secondary root branching. Both isomerization to the cis isomer and the presence of the plant reduced the concentration of trans-FA in the nutrient solution during the two weeks exposure period. A third experiment was conducted to assess the influence of irradiance on the phytotoxicity of FA. At a light intensity of 489 μmol m-2 s-1, or in the presence of microorganisms, the concentration of FA in the nutrient solution was lowered and the phytotoxic effects were reduced.

Distribution of 14C from ingested, radiolabelled dichlorostearic, stearic and oleic acids in body and in lipids of perch, Perca fluviatilis

Distribution of C-14 from ingested, radiolabelled dichlorostearic, stearic and oleic acids in body and in lipids of perch, Perca fluviatilis

Bacterial amelioration of ferulic acid toxicity to hydroponically grown lettuce (Lactuca sativa L.)

Ferulic acid (FA) is released from plant roots and by decomposition of plant residues and may be involved in allelopathic interactions. We isolated bacteria from the recirculating nutrient solution of a closed, hydroponic lettuce culture using nutrient media supplemented with 1.0 mM FA. The isolates were tested for their capacity to degrade FA in concentrations up to 200 μM. Isolates p208, p210 and p307 showed the highest degradation rates and were therefore used for single- and multiple-strain inoculation in two factorial experiments where lettuce (Lactuca sativa L. cv. Grand Rapids) plants were grown gnotobiotically for 2 weeks in nutrient solution with or without 200 μM FA. When isolate p208 or multiple strains were added, no FA was detectable at the end of the experiments. In the absence of FA, no significant effects of the bacterial treatments could be found with respect to plant dry weight. However, in the presence of FA, isolate p210 increased shoot dry weight and the multiple-strain treatment increased root and shoot dry weights in the first experiment. In the second experiment, isolate p210 neither affected the concentration of FA nor plant dry weights. Isolate p208 and the multiple-strain treatment reduced the negative effect of FA on lateral root lengths and root hair formation in both experiments. Finally, we conclude that bacteria with the capacity to degrade FA and to ameliorate phytotoxic effects of FA were present in the nutrient solution of a commercial hydroponic lettuce culture.

Halogenated fatty acids: II. Methods of determination in lipids

Abstract Halogenated fatty acids are the major contributors to organohalogen compounds in lipids of marine mammals, fish, and bivalves. For the initial characterization of these recently noticed compounds, a determination of the halogen concentration has usually been combined with some lipid isolation and separation method. This review covers separation by solid phase chromatography, gel permeation chromatography, and liquid-liquid extraction, followed by halogen determination. All studies performed according to this outline have indicated that the major organohalogen compounds are chlorinated fatty acids bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD), atomic emission spectrometry, and mass spectrometry. For most environmental samples, chlorinated FAMEs must be enriched prior to GC. ELCD is a useful detection method for indicating halogenated FAMEs in the chromatograms, and tentative identification of the halogenated species can be obtained by calculation of retention indices. For closer identification of halogenated FAMEs, mass spectrometry (MS) is very useful, in particular when employing the chemical ionisation mode. MS identification, however, is highly facilitated if halogenated species are first indicated by element-selective methods.

Occurrence of halogenated fatty acids in bivalve lipids

Environmental pollutants account for 1–3% of the extractable, organically bound chlorine (EOCl) found in bivalve lipids. In this work, bivalve lipids were converted to fatty acid methyl esters (FAMEs). The EOCl in the FAMEs and in acidic compounds was examined after liquid-liquid extraction using neutron activation analysis for chlorine determination. Gas chromatography with halogen selective, electrolytic conductivity detection (GC/ELCD) was employed to study the occurrence of halogenated FAMEs. Following esterification, most of the EOCl was recovered in the FAME-containing fraction. However, silica gel chromatography showed that more than 50% of the EOCl consisted of compounds of higher polarity than the chlorinated FAMEs normally found in fish extracts. By using GC/ELCD, up to 25% of the EOCl was detected as halogenated fatty acids. A complex pattern of halogenated fatty acids was found in bivalves from the Baltic Sea. This pattern was simplified to one consisting of only a few halogenated fatty acids in bivalves from West Scandinavian waters. These acids seem to persist in the ecosystem. It is possible that up to 40% of the EOCl remained in a brown, organic material of polar character that was coextracted with the FAMEs.

Evaluation of chromatographic methods for the detection of bacterial contamination in biotechnical processes

Abstract Chromatographic methods were evaluated concerning their effectiveness in the detection of bacterial contaminations of cultures of Leuconostoc mesenteroides , a Gram-positive bacterium used for industrial production of dextran. Three classes of cellular components were studied: fatty acids, amino acids and carbohydrates. Proportions of Staphylococcus and Bacillus as small as 0.25% (w/w), and 0.5% Streptococcus , could be detected in L. mesenteroides cell suspensions by determination of fatty acid chemical markers. In addition, the effect of bacterial contamination on chromatographic profiles was studied by comparing the profiles of non-contaminated L. mesenteroides with those of L. mesenteroides contaminated with a strain of Enterobacter cloacae isolated at a dextran-producing industry. The noted differences in the profiles were evaluated using a multivariate classification program (SIMCA). The results indicate that sensitive chromatographic methods for the determination of cellular components may be versatile tools for the early detection of bacterial contamination in biotechnical processes.