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3. Dicarbonsäuren, kurzkettige – Bestimmung von Oxalsäure, Malonsäure, Bernsteinsäure, Glutarsäure und Adipinsäure in der Luft am Arbeitsplatz mittels Ionenchromatographie (IC)

Author

Prott, Ulrich, Hebisch, Ralph, Breuer, Dietmar, Hartwig, Andrea, and MAK Commission

Subjects
Ethandisäure, 1,5-Pentandisäure, 1,4-Butandicarbonsäure, Succinylsäure, n-Pyrotartaric acid, E355, Messbereich, Propanedioic acid, Hexandisäure, Oxalic acid dihydrate, Malonsäure, Luftanalysen, hazardous substance, Ethandicarbonsäure, Oxalic acid, Wiederfindung, Leitfähigkeitsdetektor, Propandisäure, air analyses, 1,3-Propanedicarboxylic acid, ion chromatography, 10-point calibration, Kleesäure, E363, Ethandisäuredihydrat, Präzision, workplace measurement, analytical method, Selektivität, GSP-Probenahmekopf, Gefahrstoff, glass fiber filter, Hexane-1,6-dioic acid, Bestimmungsgrenze, external calibration, Malonic acid, Ionenchromatographie mit Leitfähigkeitsdetektion, Luft, Ethanedioic acid dihydrate, GSP sampling head, Butan-1,4-dicarbonsäure, Butanedioic acid, kurzkettig, 10-Punkt-Kalibrierung, conductivity detector, Pentandisäure, Externe Kalibrierung, sampling, Oxalsäuredihydrat, ion chromatography with conductivity detection, measurement range, Acifloctin, air, short chained, Succinic acid, recovery, Ionenchromatographie, Ethanedioic acid, Glasfaserfilter, Arbeitsplatzmessung, Ethanedicarbonic acid, Probenahme, IC, selectivity, Glutarsäure, 1,6-Hexandisäure, Adipic acid, Kleesäuredihydrat, Propan-1,3-dicarbonsäure, 1,4-Butanedicarboxylic acid, Pentanedioic acid, Methanedicarbonic acid, Propane-1,3-dicarboxylic acid, Adipinsäure, Glutaric acid, Hexanedioic acid, Analysenmethode, 1,4-Dicarboxylbutan, Butane-1,4-dicarboxylic acid, Methandicarbonsäure, Butandisäure, precision, 1,3-Propandicarbonsäure, Bernsteinsäure, limit of quantification, Oxalsäure
Abstract

The analytical method described here permits the determination of five linear chain aliphatic dicarboxylic acids with 2 to 6 carbon atoms and terminal carboxy groups occurring as inhalable particles in workplace air. The concentration range covers one tenth up to twice the currently valid Occupational Exposure Limit Value (OELV) in Germany, which is 1 mg/m3 for oxalic acid and 2 mg/m3 for succinic, glutaric and adipic acid (inhalable fraction). The peak limitation with an excursion factor of 2 can also be checked. At the moment, there is no OELV for malonic acid, so the same concentration range has been considered as for oxalic acid. Sampling is performed using a flow-regulated pump to draw a defined volume of air through a glass fibre filter, which is alkaline-impregnated with sodium carbonate and inserted in a GSP sampling system. The volumetric flow rate is 10 l/min. For sampling, 2 hours or 15 minutes can be used. The collected dicarboxylic acid deposited on the filter is extracted by means of an aqueous sodium carbonate/sodium hydroxide solution and analysed by means of ion chromatography using a conductivity detector. Quantitative determination is based on multiple-point calibrations with external standards. For an air sample volume of 1200 litres, the relative limit of quantification (LOQ) is in the range from 0.0002 mg/m3 for oxalic acid and 0.0009 mg/m3 for succinic acid. With LOQs less than 0.0076 mg/m3, the measurement of the short-term exposure limit (STEL) is also enabled with an air sample volume of 150 litres. The recoveries of the five dicarboxylic acids range from 96% to 110% and the expanded uncertainty is less than 29%.

Published
2022
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7. Multiplexed Workplace Measurements in Biogas Plants Reveal Compositional Changes in Aerosol Properties

Author

Pöther, Dierk-Christoph, Schneider, Daniela, Prott, Ulrich, Karmann, Jörg, Klug, Kerstin, Heubach, Nancy, Hebisch, Ralph, and Jäckel, Udo

Abstract

Anaerobic digestion is an emerging technology producing energy from renewable resources or food waste. Exposure screenings, comprising hazardous substances and biological agents, at different workplaces are necessary for a comprehensive overview of potential hazards in order to assess the risk of employees in biogas plants. In order to analyse these parameters, workplace measurements were conducted in seven full-scale anaerobic digesters. Personal and stationary sampling was performed for inhalable and respirable particles, volatile organic compounds, ammonia, hydrogen sulphide, carbon monoxide, and carbon dioxide. Furthermore, concentrations of the total cell count, endotoxins, and fungi—down to species level—were determined in comparison to windward air. Sequencing of the 16S rRNA genes was utilized for the determination of the bacterial composition inside the biogas plants. Measurements of hazardous substances show hardly values reaching the specific occupational exposure limit value, except ammonia. An approximate 5-fold increase in the median of the total cell count, 15-fold in endotoxins, and 4-fold in fungi was monitored in the biogas plants compared with windward air. Specifying the comparison to selected workplaces showed the highest concentrations of these parameters for workplaces related to delivery and cleaning. Strikingly, the fungal composition drastically changed between windward air and burdened workplaces with an increase of Aspergillusspecies up to 250-fold and Penicilliumspecies up to 400-fold. Sequence analyses of 16S rRNA genes revealed that many workplaces are dominated by the order of Bacillales or Lactobacillales, but many sequences were not assignable to known bacteria. Although significant changes inside the biogas plant compared with windward air were identified, that increase does not suggest stricter occupational safety measures at least when applying German policies. However, exposure to biological agents revealed wide ranges and specific workplace measurements should be conducted for risk assessment.

Published
2021
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