Formamide, dimethylformamide – Determination of formamide in urine by gas chromatography mass spectrometry : Biomonitoring Methods, 2018

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area verified the presented biomonitoring method. The method described herein allows the determination of formamide in urine by gas chromatography mass spectrometry (GC‐MS). Due to its sensitivity, this method is suitable for the detection of occupational and environmental exposure to formamide. For the analytical determination 1 mL of urine is lyophilised after being spiked with 13C,15N‐formamide as the internal standard. The lyophilisate is extracted with 200 µL methanol. After centrifugation, 1 µL of the extract is injected into a GC‐MS system. The method was extensively validated and the reliability data were confirmed by an independent laboratory, which has established and cross‐checked the whole procedure

Tabakspezifische Nitrosamine – Bestimmung von N‐Nitrosoanabasin, N‐Nitrosoanatabin, N‐Nitrosonornikotin und 4‐(Methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol in Urin mittels LC‐MS/MS : Biomonitoring methods in German language, 2019

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and validated the presented biomonitoring method. This analytical method permits the determination of tobacco‐specific nitrosamines (TSNA) in urine using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). The parameters in question are N‐nitrosoanabasine (NAB), N‐nitrosoanatabine (NAT), N‐nitrosonornicotine (NNN) and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol (NNAL). NNAL is a metabolite of 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK). Due to its sensitivity, this method is suitable for the detection of the aforementioned analytes in the urine of smokers. NNAL can also be quantified in the urine of passive smokers. The analytes NAB, NAT, NNN and NNAL are present in urine in both free and glucuronidated forms. For the determination of the total TSNA level in urine, the glucuronides are cleaved by enzymatic hydrolysis and then the analytes are isolated and concentrated using solid phase extraction (SPE). Two sorbent materials are used for sample preparation via SPE, first a material based on molecularly imprinted polymers and then a mixed‐mode cation exchange polymer. Analysis is performed by LC‐MS/MS. Deuterated internal standards are used for calibration. Calibration standards are prepared in pooled urine obtained from non‐smokers and are processed in the same way as the samples to be analysed

Tobacco‐specific nitrosamines – Determination of N‐nitrosoanabasine, N‐nitrosoanatabine, N‐nitrosonornicotine and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol in urine by LC‐MS/MS : Biomonitoring methods, 2019

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and validated the presented biomonitoring method. This analytical method permits the determination of tobacco‐specific nitrosamines (TSNA) in urine using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). The parameters in question are N‐nitrosoanabasine (NAB), N‐nitrosoanatabine (NAT), N‐nitrosonornicotine (NNN) and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol (NNAL). NNAL is a metabolite of 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK). Due to its sensitivity, this method is suitable for the detection of the aforementioned analytes in the urine of smokers. NNAL can also be quantified in the urine of passive smokers. The analytes NAB, NAT, NNN and NNAL are present in urine in both free and glucuronidated forms. For the determination of the total TSNA level in urine, the glucuronides are cleaved by enzymatic hydrolysis and then the analytes are isolated and concentrated using solid phase extraction (SPE). Two sorbent materials are used for sample preparation via SPE, first a material based on molecularly imprinted polymers and then a mixed‐mode cation exchange polymer. Analysis is performed by LC‐MS/MS. Deuterated internal standards are used for calibration. Calibration standards are prepared in pooled urine obtained from non‐smokers and are processed in the same way as the samples to be analysed

Formamid, Dimethylformamid – Bestimmung von Formamid in Urin mittels Gaschromatographie‐Massenspektrometrie : Biomonitoring Methods in German language, 2018

The working group „Analyses in Biological Materials“ of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area verified the presented biomonitoring method. The method described herein allows the determination of formamide in urine by gas chromatography mass spectrometry (GC‐MS). Due to its sensitivity, this method is suitable for the detection of occupational and environmental exposure to formamide. For the analytical determination 1 mL of urine is lyophilized after being spiked with 13C,15N‐formamide as the internal standard. The lyophilisate is extracted with 200 µL methanol. After centrifugation, 1 µL of the extract is injected into a GC‐MS system. The method was extensively validated and the reliability data were confirmed by an independent laboratory, which has established and cross‐checked the whole procedure

Grain Size Influence on the Magnetic Property Deterioration of Blanked Non-Oriented Electrical Steels

Non-oriented electrical steel sheets are applied as a core material in rotors and stators of electric machines in order to guide and magnify their magnetic flux density. Their contouring is often realized in a blanking process step, which results in plastic deformation of the cut edges and thus deteriorates the magnetic properties of the base material. This work evaluates the influence of the material’s grain size on its iron losses after the blanking process. Samples for the single sheet test were blanked at different cutting clearances (15 µm–70 µm) from sheets with identical chemical composition (3.2 wt.% Si) but varying average grain size (28 µm–210 µm) and thickness (0.25 mm and 0.5 mm). Additionally, in situ measurements of blanking force and punch travel were carried out. Results show that blanking-related iron losses either increase for 0.25 mm thick sheets or decrease for 0.5 mm thick sheets with increasing grain size. Although this is partly in contradiction to previous research, it can be explained by the interplay of dislocation annihilation and transgranular fracturing. The paper thus contributes to a deeper understanding of the blanking process of coarse-grained, thin electrical steel sheets