TY - JOUR A1 - Willms, Thomas A1 - Kryk, Holger A1 - Hampel, Uwe T1 - An improved method for the analysis of the reaction products of the partial isobutane oxidation by gas chromatography using a green solvent N2 - In the present work, an improved GC/MS method for the analysis of the reaction products of the non-catalytic partial oxidation of isobutane at a starting temperature of 25°C has been developed and compared to a previously published method. Two green GC-solvents (dimethyl carbonate (DMC), diethyl carbonate (DEC)) and several internal standards (hexane, benzene, toluene, DEC) have been tested. The separation of the products at low retention times (methanol, isobutane, isobutene) could be significantly improved. For the liquid main products t-butyl hydroperoxide (TBHP), di-t-butyl peroxide (DTBP), t-butanol (TBA), propanone and most trace products (isopropanol, isobutanal, methyl formate, isopropyl formate, t-butyl formate and some acetates – 24 compounds in total), a coefficient of determination CoD > 0.999 has been achieved. For all weighing and GC/MS measurements uncertainties have been calculated. The peaks of the peak pair t-butyl formate (CoD >0.999) and isobutanol (CoD >0.99), have been simulated and used for calibrations. DEC gave a decomposition of TBHP on the column. With DMC, a problem of peak purity of TBHP appeared but could be resolved. The use of the green solvent DMC, compared to also studied traditional solvents like heptane and toluene, proved to be very beneficial, since it also permitted to determine polar compounds, e. g. carbon dioxide and formic acid. KW - GC/MS KW - Green solvent KW - Method development KW - Peroxide KW - Measurement uncertainties KW - Oxidation products KW - Simulation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632026 DO - https://doi.org/10.1016/j.chroma.2025.465892 SN - 0021-9673 VL - 1753 SP - 1 EP - 16 PB - Elsevier CY - Amsterdam AN - OPUS4-63202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wilke, Olaf A1 - Poelke, Birte A1 - Klein, Luise A1 - Rohloff, Alexander A1 - Hoffmann, Holger T1 - Initial VOC Emissions from Consumer Products Determined in Micro-Scale Test Chambers: Results of a Round Robin Test N2 - Emissions of volatile organic compounds (VOCs) from consumer products may have a negative impact on indoor air quality, potentially also affecting human wellbeing. Since consumers may be exposed to these VOCs immediately after e.g. unwrapping of newly purchased products, reliable analytical methods are needed to determine air concentration profiles in the early phase of VOC emissions. Concerning typical sample sizes of consumer products, micro-scale test chambers (μ-chambers) were considered suitable for this purpose. In addition, compared to medium- or large-scale test chambers, μ-chambers require lower initial investment and operational costs, and offer options for emissions screenings where higher sample throughput is essential. For these reasons, a μ-chamber-based method to determine initial concentrations of VOCs emitting within the first hours of simulated product use was developed. The chamber air was frequently sampled on desorption tubes loaded with Tenax® TA, followed by quantification of emitted VOCs via thermal desorption gas chromatography mass spectrometry (TD-GC-MS). The method was assessed in a round robin test involving eight participating laboratories from 2 countries. Pieces of a rain poncho (sample area A: 2.01·10-4 m2) emitting cyclohexanone, phenol, 2-ethylhexanol, naphthalene and isophorone in significant concentrations were distributed as sample material. Each laboratory conducted triplicate emission tests over a period of 48 h in μ-chambers with volumes of 44 or 114 mL. The loading factors L of 4.57 m2·m-3 (44 mL) or 1.76 m2·m-3 (114 mL) and air flow rates of 24 mL·min-1 resulted in area-specific air flow rates q of 7.17 m3·m-2·h-1 in both chamber types. The temperature was set to 23°C and, if possible, relative humidity was set to approx. 50%. The chamber air was sampled after 0.5, 1, 2, 4, 24 and 48 hours. In addition, to assess the analytical performance, each participating laboratory received two analyte-spiked Tenax® TA-loaded desorption tubes for quality control (QC). Very low relative standard deviations (11–17%) were obtained for the QC test. The results of the emissions tests in the early phase (0.5–4 h) were also adequate, with acceptable z scores (|z|≤2.00) received by six to seven participating laboratories. All eight laboratories obtained acceptable z scores after the longer sampling periods (24 and 48 h). Hence, the inter-laboratory comparability of the results obtained with the developed μ-chamber method was successfully confirmed. T2 - Healthy Buildings Europe 2025 CY - Reykjavik, Iceland DA - 08.06.2025 KW - VOC Emissions KW - Consumer Product KW - Test Chamber KW - Round Robin Test PY - 2025 AN - OPUS4-63706 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tang, Chi-Long A1 - Seeger, Stefan A1 - Röllig, Mathias T1 - Improving the comparability of FFF-3D printing emission data by adjustment of the set extruder temperature N2 - Fused filament fabrication (FFF) is a material extrusion-based technique often used in desktop 3D printers. Polymeric filaments are melted and are extruded through a heated nozzle to form a 3D object in layers. The extruder temperature is therefore a key parameter for a successful print job but also one of the main emission driving factors as harmful pollutants (e.g., ultrafine particles) are formed by thermal polymer degradation. The awareness of potential health risks has increased the number of emission studies in the past years. However, studies usually refer their calculated emission data to the printer set extruder temperature for comparison purposes. In this study, we used a thermocouple and an infrared camera to measure the actual extruder temperature and found significant temperature deviations to the displayed set temperature among printer models. Our result shows that printing the same filament feedstocks with three different printer models and with identical printer set temperature resulted in a variation in particle emission of around two orders of magnitude. A temperature adjustment has reduced the variation to approx. one order of magnitude. Thus, it is necessary to refer the measured emission data to the actual extruder temperature as it poses a more accurate comparison parameter for evaluation of the indoor air quality in user scenarios or for health risk assessments. KW - Ultrafine particles KW - Infrared thermography KW - Thermocouple KW - Indoor air quality KW - FFF-3D printer PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572842 DO - https://doi.org/10.1016/j.aeaoa.2023.100217 VL - 18 SP - 100217 PB - Elsevier Ltd. CY - Amsterdam, Niederlande AN - OPUS4-57284 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tang, Chi-Long A1 - Seeger, Stefan T1 - Measurement of sub-4 nm particle emission from FFF-3D printing with the TSI Nano Enhancer and the Airmodus Particle Size Magnifier N2 - The emission of ultrafine particles from small desktop Fused Filament Fabrication (FFF) 3D printers has been frequently investigated in the past years. However, the vast majority of FFF emission and exposure studies have not considered the possible occurrence of particles below the typical detection limit of Condensation Particle Counters and could have systematically underestimated the total particle emission as well as the related exposure risks. Therefore, we comparatively measured particle number concentrations and size distributions of sub-4 nm particles with two commercially available diethylene glycol-based instruments – the TSI 3757 Nano Enhancer and the Airmodus A10 Particle Size Magnifier. Both instruments were evaluated for their suitability of measuring FFF-3D printing emissions in the sub-4 nm size range while operated as a particle counter or as a particle size spectrometer. For particle counting, both instruments match best when the Airmodus system was adjusted to a cut-off of 1.5 nm. For size spectroscopy, both instruments show limitations due to either the fast dynamics or rather low levels of particle emissions from FFF-3D printing in this range. The effects are discussed in detail in this article. The findings could be used to implement sub-4 nm particle measurement in future emission or exposure studies, but also for the development of standard test protocols for FFF-3D printing emissions. KW - Air pollution KW - Ultrafine particles KW - Sub-4nm particles KW - FFF-3D printing KW - Emission testing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595952 DO - https://doi.org/10.1080/02786826.2024.2320430 SN - 0278-6826 VL - 58 IS - 6 SP - 644 EP - 656 PB - Taylor & Francis CY - London AN - OPUS4-59595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tang, Chi-Long T1 - Sub-4 nm particles from FFF-3D printing measured with the TSI 1 nm CPC and the Airmodus A11 nCNC N2 - Concerns have been raised as Fused Filament Fabrication (FFF) desktop 3D printer emits harmful ultrafine particles (dP < 100 nm) during operation in indoor spaces. However, the vast majority of previous emission studies have neglected the possible occurrence of sub-4 nm particles by using conventional condensation particle counter (CPC) for detection. Thus, the total particle emission could be systematically underestimated. This study has compared two diethylene glycol (DEG) based instruments to evaluate their suitability for measuring organic FFF particles in the sub-4 nm size range either as particle counter or as a particle size spectrometer. T2 - European Aerosol Conference 2024 CY - Tampere, Finland DA - 25.08.2024 KW - Air pollution KW - Emission testing KW - FFF-3D printing KW - Sub-4nm particles KW - Ultrafine particles PY - 2024 AN - OPUS4-60930 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tang, Chi-Long T1 - Minimizing the FFF-3D printer hardware bias on particle emission by adjustment of the set extruder temperature N2 - Fused filament fabrication (FFF) on desktop 3D printers is a material extrusion-based technique often used by educational institutions, small enterprises and private households. Polymeric filaments are melted and extruded through a heated nozzle to form a 3D object in layers. The extrusion temperature is therefore a key parameter for a successful print job, but also one of the main driving factors for the emission of harmful air pollutants, namely ultrafine particles and volatile organic gases, which are formed by thermal stress on the polymeric feedstock. The awareness of potential health risks has increased the number of emission studies in the past years. However, the multiplicity of study designs makes an objective comparison of emission data challenging because printer hardware factors such as the actual extruder temperature (TE) and also feedstockspecific emissions are not considered. We assume that across the market of commercial low- and mid-price FFF printers substantial deviations between actual and set extruder temperatures exist, which have a strong effect on the emissions and hence may bias the findings of exposure studies. In our last publication, we presented a standardized feedstock-specific emission test method and showed that for each investigated feedstock an increase in actual extruder temperature was accompanied by an increase in particle emissions (Tang and Seeger, 2022). Therefore, any systematic discrepancy between set and actual extruder temperature matters. In this study, we used a thermocouple and an infrared camera to measure the actual extruder temperatures at different heights. We found significant under- and overestimation of the actual extruder temperatures by the respective set temperatures in three commercial printers. This caused a broad variation of the measured total numbers of emitted particles (TP), even when the same feedstock was operated. For the determination of TP, we followed the DE-UZ 219 test guideline. In a second round we repeated the tests with all printers adjusted to exactly the same extruder temperatures, i.e., to TE=230°C for ABS and TE=210°C for PLA. All measurements were conducted in a 1 m³ emission test chamber. Particle emissions in the size range between 4 nm and 20 μm were detected. Printing on three different printer models without temperature adjustment resulted for each of the investigated feedstocks in a variation in TP of around two orders of magnitude. After temperature adjustment, this was substantially reduced to approx. one order of magnitude and hence minimizes the bias of printer hardware on the emissions. Our findings suggest that adjustment of the extruder temperature should be mandatory in emission testing standards. It also poses a more accurate benchmark and provides more reliable emission data for evaluation of indoor air quality or for health risk assessments. In addition, a proper temperature setting is in the interest of the user. Some commercial FFF printers may have a higher actual extruder temperature than displayed and unintended overheating may not only impair the print quality but may cause unnecessarily increased exposure to particle emissions. T2 - European Aerosol Conference 2023 CY - Málaga, Spain DA - 03.09.2023 KW - Ultrafine particles KW - Thermal imaging KW - 3D printing KW - Indoor air quality KW - Emission testing PY - 2023 AN - OPUS4-58258 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Taghavi Kalajahi, Sara A1 - Misra, Archismita A1 - Koerdt, Andrea T1 - Nanotechnology to mitigate microbiologically influenced corrosion (MIC) N2 - Microbiologically influenced corrosion (MIC) is a crucial issue for industry and infrastructure. Biofilms are known to form on different kinds of surfaces such as metal, concrete, and medical equipment. However, in some cases the effect of microorganisms on the material can be negative for the consistency and integrity of the material. Thus, to overcome the issues raised by MIC on a system, different physical, chemical, and biological strategies have been considered; all having their own advantages, limitations, and sometimes even unwanted disadvantages. Among all the methods, biocide treatments and antifouling coatings are more common for controlling MIC, though they face some challenges. They lack specificity for MIC microorganisms, leading to cross-resistance and requiring higher concentrations. Moreover, they pose environmental risks and harm non-target organisms. Hence, the demand for eco-friendly, long-term solutions is increasing as regulations tighten. Recently, attentions have been directed to the application of nanomaterials to mitigate or control MIC due to their significant antimicrobial efficiency and their potential for lower environmental risk compared to the conventional biocides or coatings. Use of nanomaterials to inhibit MIC is very new and there is a lack of literature review on this topic. To address this issue, we present a review of the nanomaterials examined as a biocide or in a form of a coating on a surface to mitigate MIC. This review will help consolidate the existing knowledge and research on the use of nanomaterials for MIC mitigation. It will further contribute to a better understanding of the potential applications and challenges associated with using nanomaterials for MIC prevention and control. KW - Microbiologically influenced corrosion (MIC) KW - Biofilm KW - Biofouling KW - Nanobiocide KW - Nanocoating PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599335 DO - https://doi.org/10.3389/fnano.2024.1340352 SN - 2673-3013 VL - 6 SP - 1 EP - 25 PB - Frontiers Media CY - Lausanne AN - OPUS4-59933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Strzelczyk, Rebecca T1 - Zeolites loaded with VOCs as reference for material emissions testing N2 - Nowadays, people spend most of their time indoors. Thus, a good indoor air quality is important. Emissions of volatile organic compounds (VOCs) from furniture and building materials can cause health complaints1. Quantitative VOC-emission testing is carried out under standardized conditions in emission test chambers. In the presented project an emission reference material (ERM) is developed that emits a defined mixture of VOCs which is required for quality assurance and -control (QA/QC) measures. Porous materials (e.g zeolites, activated carbons, MOFs or aerogels) are used as reservoir materials and impregnated with VOC. The porous materials are selected, among others, by their pore size, pore size distribution, polarity and availability. Due to their regular pore structure zeolites are tested at first. For a prediction of the emission profile, the ERM is supposed to exhibit a constant emission rate over time. The aim is a stability of ≤ 10 % change in the emission rate over a minimum of 14 days. Method For impregnation, the material is placed into an autoclave inside a rotatable basket. The VOC is added and the autoclave is closed. Afterwards, CO2 is inserted. The closed system is then heated to the supercritical point of CO2 (31 °C, 73.75 bar). In this state, the CO2 acts as solvent for the VOC. By rotating the basket, the distribution of the VOC is ensured. After a few minutes, the pressure is decreased slowly and the CO2 is released. For the determination of the emission profile, the impregnated sample is placed into an emission test chamber. These chambers can be operated either with dry or humid air (50 ± 5 % rel. humidity). Every second to third day, air samples are taken and analyzed by gas chromatography. For an ideal impregnation, several different pressures and temperatures as well as impregnation times are tested. Results Two zeolite materials tested in dry air conditions reach emission profiles with a decrease of less than 10 % over 14 days (heptane and toluene, respectively). Further it was discovered that smaller pellets of the same zeolite show better results than bigger particles. When the pore size of a zeolite is too small, e.g. 0.3 nm, the VOC cannot be absorbed sufficiently. The main disadvantage of zeolites is their hygroscopicity because it has a large impact on the release of VOC when they are used in emission test chambers under standardized test conditions (23 °C, 50 % rel. humidity). Activated carbons have emission profiles with a larger change over 14 days. However, the high hydrophobicity allows measurements in humid air conditions which was not possible with the before mentioned hygroscopic zeolites. It is possible to impregnate powdered materials as well, and thus powdered non-hygroscopic (n.h.) zeolites were impregnated. Their emission profiles are comparable to those of the activated carbons. The use of methylated hygroscopic zeolites with a decrease in hygroscopicity did not yield successful emission measurements. The change over 14 days is calculated only for the stable phase (~250–300 h). The desired stability of ≤ 10 % change of the emission rate over 14 days could already be reached under dry testing conditions. Further investigations under humid conditions show that zeolites with high Si/Al-ratios are non-hygroscopic and comparable to activated carbons (20–30 % change). The next step is to reduce the change in the emission rate of these materials to the aimed ≤ 10 % over 14 days. T2 - Deutsche Zeolithtagung CY - Jena, Germany DA - 28.02.2024 KW - VOC KW - Emission KW - Quality assurance KW - Reference material KW - Zeolite PY - 2024 AN - OPUS4-59843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Steger, Simon A1 - Stege, H. A1 - Bretz, S. A1 - Hahn, Oliver ED - Tomasin, P. T1 - Disclosing glittering and sparkling effects in 20th-century reverse glass paintings: a study of metallic pigments and metal foils by means of in situ XRF and DRIFTS analysis N2 - This work presents a spectroscopic study of metallic pigments and metal foils used in reverse glass paintings that were created between 1912 and 1954. Metallic pigments induce a notable sparkling effect by means of the lateral incidence of light, whereas metal foils enhance the gloss and create a glittering effect when the painting is viewed in reflected light. Both effects were desired features especially in modern reverse paintings on glass and applied by artists in manifold creative manner. The paper gives an overview on the composition of the metalfoils and metal pigments in 14 works as determined in situ by X-ray spectrometry. Metal foils made of tin, brass, aluminium and silver were found in nine paintings. Gold imitating Cu-Zn pigments in different hues and with various Cu/Zn net intensity ratios were recorded for six paintings. Silvery pigments were identified mainly as Al pigments, but also as Cu-Zn-Ni alloy in one case. Other uncommon metallic pigments were detected in Arlequin vindicatif (c. 1925) by Floris Jespers, who used not only Cu-Zn and Al pigments, but also brownish Cu and Cu-Zn-Sn pigments. Non-invasive diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) was used to classify the binding media of the metallic pigments. Drying oil and natural resin probably mixed with oil were the most common binding media. A polysaccharide-based binder was found in the silvery Cu-Zn-Ni pigment of Ohne Titel (1954) by Marianne Uhlenhuth. KW - Archaeometry KW - Non-invasive analysis KW - Reverse paintings on glass PY - 2020 DO - https://doi.org/10.1016/j.culher.2020.11.008 SN - 1296-2074 VL - 48 SP - 196 EP - 204 PB - Elsevier Masson SAS CY - Amsterdam AN - OPUS4-54428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steger, Simon T1 - Spectroscopic analysis of colourants and binders of Chinese reverse glass paintings tracing a cultural dialogue N2 - Scientific analysis based on spectroscopic methods provide essential information on the composition of colourants and binders in paintings. These results can be set in a historical context and help to confirm art historical interpretations. Proofs of certain pigments can be used for dating purposes and may reveal if the artist used not only local but also imported materials. A pilot study of two Chinese reverse glass paintings from the late 19th (Yingying and Hongniang) and early 20th centuries (The Archer) was performed using a multi-analytical approach including X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and Raman spectroscopy. This approach allowed the identification of the pigments and the classification of the binding media. The results reveal a combined use of traditional Chinese and imported European materials. Several pigments like cinnabar, lead white, orpiment, carbon black and copper-arsenic green (probably emerald green) were found in both paintings; red lead, artificial ultramarine blue, Prussian blue and ochre appear in at least one of the paintings. The proof of limewash (calcite and small amounts of portlandite) as a backing layer in “Yingying and Hongniang” indicates that clamshell white was also used for reverse glass paintings. Drying oil was classified as a binding media in most areas of both paintings. However, the orange background of The Archer yielded prominent bands of both proteinaceous and fatty binder. T2 - China and the West Reconsidering Chinese Reverse Glass Painting CY - Romont, Switzerland DA - 14.02.2020 KW - Reverse glass painting KW - DRIFTS KW - Raman spectroscopy PY - 2020 AN - OPUS4-50445 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -