Związki manganu, niklu i żelaza. Metoda oznaczania w powietrzu na stanowiskach pracy

The aim of this study was to develop and validate a method for determining of inhalable and respirable fraction of compounds of manganese, nickel and iron in workplace air. The method is based on passing the tested air through a filter from the cellulose ester mixture placed in a specific sampler. The filter mineralizes in concentrated nitric acid (V) and makes a solution for analysis in diluted nitric acid (V). The use of different dilutions of the sample solution after mineralization makes it possible to use the ranges of standard curves for the determination of substances as manganese, nickel and iron. The addition of lanthanum salt (correction buffer) prevents the occurrence of chemical interference, the use of deuterium lamp eliminates background interference. The developed method enables the determination of selected substances in the air of the working environment in the concentration ranges corresponding to the range from 0.1 to 2 MACs values and also enables the determination of nickel and its compounds in the inhalable fraction for the currently proposed new value of the maximum permissible concentration. The developed method has been validated in accordance with the requirements of Standard No. PN-EN 482 and good validation results were obtained. The method can be used for assessing occupational exposure to compounds of manganese, nickel and iron and associated risk to workers’ health. The developed method of determining compounds of manganese, nickel and iron has been recorded as an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Ultraviolet absorption of contaminants in water

Contaminants in water were studied using ultraviolet absorption with light emitting diode and deuterium lamp sources, and a thresholding detector. The absorption spectra of potassium hydrogen pthalate, clothianidin, tryptophan, thiamethoxam, uric acid and metaldehyde were obtained in the range 200–360 nm. Only metaldehyde was not suitable for detection in this range. For the other contaminants, and mixtures of pairs of compounds, the transmitted signal could be approximately described with a simple spectral model of the source–absorption–detector system. Combined measurements at two wavelengths could allow relative concentrations in certain mixtures to be determined, and real-time absorption measurements were demonstrated in a flume.

Minimizing Chloride Interferences Produced by Calcium Chloride in the Determination of Cd by Graphite Furnace Atomic Absorption Spectrometry

Cadmium concentrations in CaCl2 extracting solutions at various concentrations were determined by graphite furnace atomic absorption using two background correctors: the deuterium and the high-speed self-reversal background correction systems. Under- and overestimation of the Cd absorbance signals in CaCl2 solutions were observed for concentrations greater than 0.005 M using the deuterium lamp while no important effect was observed using the other background correction system. The analytical performance of the spectrometer for the determination of Cd was studied in 0.01 M CaCl2 solution and single extractions were performed using reference materials and contaminated soil samples. Cadmium was determined using the two background correction systems and a third method, which consists of the use of the deuterium lamp without any chemical modifier, was added to the study. The results showed that the third method was unable to determine Cd concentrations in the CaCl2 solution due to the presence of extractable arsenic and iron. For solutions without any dilution or diluted with a very low dilution factor, the CaCl2-extractable Cd concentrations measured using the deuterium lamp were systematically below those found using the high-speed self-reversal method. These differences were explained by the presence of chloride ions in the atomization step.

Effects of Iron Concentration Level in Extracting Solutions from Contaminated Soils on the Determination of Zinc by Flame Atomic Absorption Spectrometry with Two Background Correctors

Zinc and iron concentrations were determined after digestion, water, and three-step sequential extractions of contaminated soils. Analyses were carried out using flame absorption spectrometry with two background correctors: a deuterium lamp used as the continuum light source (D2method) and the high-speed self-reversal method (HSSR method). Regarding the preliminary results obtained with synthetic solutions, the D2method often emerged as an unsuitable configuration for compensating iron spectral interferences. In contrast, the HSSR method appeared as a convenient and powerful configuration and was tested for the determination of zinc in contaminated soils containing high amounts of iron. Simple, fast, and interference-free method, the HSSR method allows zinc determination at the ppb level in the presence of large amounts of iron with high stability, sensitivity, and reproducibility of results. Therefore, the HSSR method is described here as a promising approach for monitoring zinc concentrations in various iron-containing samples without any pretreatment.