Analysis Of Microcontaminants Research Articles

Analysis of Micro-Contaminants in Solid Particles from Direct Injection Gasoline Vehicles

Exhaust emissions from vehicles are the subject of numerous studies and legal acts. In the European Union, exhaust emissions are regulated by “Euro” emission standards, which limit emissions of gaseous pollutants such as CO, CO2, HC, and NOx, as well as the particulate matter (PM) and particle number (PN). Solid particles consist of a number of micro-contaminants, inter alia polycyclic aromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives. Despite their highly mutagenic and carcinogenic character, these micro-contaminants are not regulated in Euro emissions standards. This paper presents both a general discussion of the phenomenon of particulate formation in and emission from direct injection gasoline engines, as well as a wide range of results on the subject. The subject of the micro-contaminants in solid particles from modern gasoline vehicles is explored. The samples of solid particles were collected from 11 groups of vehicles according to the WLTP test methodology. Solid particles from gasoline vehicles were analyzed via various analytical techniques, including ion chromatography (IC) to measure selected anion concentrations, gas chromatography with mass spectroscopy (GC-MS) to study 16 PAHs and selected PAH derivatives, scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) for images and elemental composition, and microwave plasma atomic emission spectroscopy (MP-AES) for qualitative screening analysis of 19 elements. The study of non-regulated compounds is crucial in efforts to establish the influence of solid particles on health and the environment. Furthermore, extended studies can provide a basis for further research on vehicle emissions or other fields, such as medicine or material engineering.

Application of a voltammetric enzymatic biosensor based on crude extract of Marasmiellus colocasiae for the detection of phenolic compounds in drinking water

The chemical and pharmaceutical industries are the main generators of residues, such as phenolic microcontaminants, including catechol, resorcinol, p-nitrophenol and 4-chlorophenol. Therefore, this work aims to identify these microcontaminants through an emerging contaminant biosensor by means of an enzymatic biosensor constructed with an enzymatic extract from the fungus Marasmiellus colocasiae. Based on the differential pulse voltammetry electrochemical technique, the biosensor was used to analyze the patterns of catechol, resorcinol, p-nitrophenol and 4-chlorophenol. The analysis of a sample prepared with these standards in water from the public supply network was also carried out. As a result, it was possible to verify that the biosensor developed in this study is more sensitive than conventional methods and has a greater affinity for catechol. In the sample prepared with the standards, it was possible to qualitatively identify the presence of 4-chlorophenol, resorcinol and catechol. The proposed biosensor was sensitive and has potential for application in the analysis of microcontaminants in the environment with the detection limit = 0.17 µmol L-1, and the quantification limit = 0.52 µmol L-1.

Analysis of microcontaminants in aqueous samples by fully automated on-line solid-phase extraction-gas chromatography-mass selective detection

The trace-level analysis of unknown organic pollutants in water requires the use of fast and sensitive methods which also provide structural information. In the present study, an on-line technique was used which combines sample preparation by means of solid-phase extraction (SPE) on a small precolumn packed with a hydrophobic phase, and capillary gas chromatography (GC) with mass spectrometric (MS) detection. Sample preparation was carried out in a fully automated SPE module which was connected to the GC system via an on-column interface. The on-column interface was selected because of its wide application range. The mass spectrometer was preferably used in the full-scan acquisition mode because of the intended identification. The total system including the SPE module, was controlled by the MS software which allowed unattended analysis of a series of samples. The feasibility of on-line SPE-GC-MS was demonstrated by analysing a variety of surface water samples in order to detect and identify non-target compounds. With a sample volume of only 10 ml various micropollutants could be identified, and also quantified, at levels below 0.1 μg/l. The system proved to be flexible, and the sample preparation could easily be adapted to analyse organochlorine pesticides by adding 30 vol.% of methanol to the raw sample. Samples were taken from several European (Axios, Greece; Ebro, Spain; Meuse, Netherlands; Nitra, Slovakia; Rhine, Germany; Thames, UK; Varta, Poland) and American (Sacramento, USA; Amazon, Brazil) rivers. An example of the identification of unknown microcontaminants in waste water is also presented, which is further evidence of the robustness and flexibility of the SPE-GC-MS analyzer.

Comparison of on-line SPE-HPLC and SPME-GC for the analysis of microcontaminants in water

Comparison of on-line SPE-HPLC and SPME-GC for the analysis of microcontaminants in water

Characterisation and analysis of micro-contaminants in industrial polymers

Analysis of very small particles can present problems. This paper describes the application of temperature programmed solid insertion probe mass spectrometry (TP-SIP-MS), scanning electron microscopy and SEM X-ray microanalysis to the identification of foreign particles present in an industrial product. The relative advantages and limitations of the techniques are discussed. It is shown that TP-SIP-MS is a powerful tool for such work and complements the use of more conventional microanalytical methods.

The role of immunoassay in the analysis of microcontaminants in water samples

Concentrations of natural and synthetic steroids and an anticancer drug (methotrexate) have been determined in water by adapting established immunoassay procedures. The limits of detection for the assays used were 10 ng/liter for norethisterone, 5 ng/liter for ethinyl estradiol and progesterone, and 6.25 ng/liter for methotrexate. Results below the level of detection were obtained in all the samples examined (8 river samples and 6 potable supply samples) except for 2 river samples (17 ng/liter) for norethisterone, and 1 river sample and 1 potable water sample for progesterone (6 ng/liter). A concentration of 1 μg/liter of methotrexate was found in a sample of hospital effluent. There appears to be no evidence of adverse effects from reused water resources which may be contaminated from the normal use of such highly active therapeutic agents.