Analytical and Bioanalytical Chemistry (v.331, #5)

Federation of European Chemical Societies (FECS) Working Party on Analytical Chemistry (WPAC) by Prof. Dr. Lauri Niinistö; Prof. Dr. Robert Kellner (465-466).
Keywords: Physical Chemistry; Analytical Chemistry; Inorganic Chemistry; Chemical Society; Working Party

Methods developed for the analysis of the organic compounds adsorbed on diesel particulate are reviewed with special emphasis on the determination of polycyclic aromatic hydrocarbons (PAH), nitro PAH and oxy PAH.
Keywords: Physical Chemistry; Analytical Chemistry; Inorganic Chemistry; Hydrocarbon; Polycyclic Aromatic Hydrocarbon

In the course of ten measuring events during spring 1985 twenty air samples were collected in Linz, an Austrian city where there is chemical and heavy industry. The collection of the air samples was carried out simultaneously at two measuring sites on both sides of the industrial area. 20 polycyclic aromatic hydrocarbons (PAH), 4 heterocyclic aromatic compounds and two aromatic ketones were determined. It was found that the concentrations of PAHs and heterocyclic aromatic compounds measured downwind of the industrial area were higher than the corresponding background values. On an average, the concentration of the tracer substance benzo[a]pyrene was twice as high (7.1 ng/ Nm3) as the urban background value (3.3 ng/Nm3).The data from Linz have been compared with analytical results from Vienna by using chemometric methods. A cluster analysis of the PAH profiles revealed a clear separation of the samples from Linz and Vienna. Substances have been determined which are characteristic of the PAH profiles in Linz.As the results of this study show, the emissions from industry lead to an additional burden of carcinogenic organic pollutants in the atmosphere of Linz.

The use of volatile halogenated hydrocarbons in manufacturing and industry has turned these substances into a severe problem for our environment. Therefore, industries and environmental protection agencies have become very interested in a rapid and trace-scale analysis of these compounds. Investigations have therefore been undertaken on the separation of such components by means of GC-ECD and GC-MS, respectively. The applicability of the analysis system elaborated is demonstrated for actual water samples and biological materials.
Keywords: Physical Chemistry; Analytical Chemistry; Inorganic Chemistry; Hydrocarbon; Water Sample

The application of a sensitive electroanalytical technique for the analysis of N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) in aerosol was investigated. Cyclic voltammetric studies of the reduction of MNNG in acidic media showed three reduction waves. The first reduction step was assigned to be the reduction of the nitroso group and the second and third steps the reduction of the nitro group. The second peak was selected for the analysis as it was found to give a constant high current at pH below 1 and it was stable up to 40 days under normal daylight exposure and bubbling air at slow flow rate. Optimised parameters for the sensitive differential pulse polarographic technique were determined and the sampling conditions were investigated. The standard addition method was used to reduce the marix interference and the peak current was measured by the difference of current before and after UV irradiation so as to eliminate the interference caused by trace metals and electroactive and UV stable organic compounds present in air. The developed method was used to analyse MNNG aerosol in an animal room. The detection limit was found to be about 3 μg/m3 for a sampling period of 48 h with a flow rate of 100 ml/min for the scrubbing method, whereas for the membrane filter method it was about 0.1 μg/m3 for a sampling period of 8h at a flow rate of 4.9 l/min.
Keywords: Differential Pulse; Nitroso; Standard Addition Method; Slow Flow; Polarography

Three different methods for nitrate determination in environmental samples were comparatively examined. The influences of Cl, NO 2 , Fe2+ and Fe3+ in different concentrations were also investigated. From the data obtained it is concluded that the cadmium reduction method is the most suitable for every type of environmental water samples. On the contrary, the electrode screening method suffers from many interferences and is not suitable for any type of sample. The direct spectrophotometric method has been found to be applicable mostly for fresh water samples.
Keywords: Nitrate; Physical Chemistry; Analytical Chemistry; Cadmium; Inorganic Chemistry

A gel-chromatographic separation system using acetone in combination with cyclohexane and petroleum ether as elution solvent is discussed. The elution patterns of more than 100 pesticides and environmental chemicals are determined with this system.
Keywords: Ether; Physical Chemistry; Analytical Chemistry; Acetone; Petroleum

An analytical procedure is described, which allows the simultaneous determination of 22 pesticides in drinking, ground and surface water.In case of higher-loaded waters the sample has to be submitted to a clean-up step after CH2Cl2 extraction. The following HPLC is carried out on a Hypersil-column, 3 μm ODS by gradient elution using CH3CN-H2O (phosphate buffer, pH 7) as eluent. The detection of the single components is achieved by a diode-array detector according to their absorption maximal at 220, 230, 245 nm, the verification being supported by comparison of the absorption spectra. As the factor of enrichment is about 1000 a detection limit of 50 μg/l for any pesticide can be obtained. The recovery is higher than 90%.

Each analytical method is to be tested for the absence of systematic errors. This is usually done by Youden's regression model, which is limited to precise “given” values. Furthermore, weighted regression allows the detection of systematic errors even if the random error of the “given” values is not to be neglected. This is demonstrated by simulation experiments and by testing a new spectrometric method for the determination of platinum.It must be taken into account that statistical tests can give information only about the presence of systematic errors (and not about their absence). Accuracy must be seen as a qualitative characteristic feature (yes/no); accuracy can never be given as a quantitative measure (more/less).

The paper criticizes the use of standard outlier tests when evaluating interlaboratory data. It is shown that many such tests are not able to detect gross outliers (masking effect). An alternative method of evaluation using tests of estimates based on robust statistics is proposed.
Keywords: Physical Chemistry; Analytical Chemistry; Inorganic Chemistry; Statistical Evaluation; Robust Statistic

A HP-5880A gas Chromatograph equipped with TCD and FID has been used to determine trace amounts of O2+Ar, N2, CO, CH4 and CO2 in pure and ultra pure hydrogen. Utilizing the preconcentration technique, the minimum detectability with a 10-liter sample is around 0.2 ppb (v/v) for O2+Ar, 0.4 ppb (v/v) for N2, 0.05 ppb (v/v) for CO, 0.2 ppb (v/v) for CH4 and 0.3 ppb (v/v) for CO2. Calculation of results in trace gas analysis is discussed and a calculation method is proposed for the concentration of impurities in the sample calculated from the difference of successive sampling volumes and peak areas.
Keywords: Hydrogen; Chromatography; Physical Chemistry; Analytical Chemistry; Inorganic Chemistry

The determinations of phenol is studied by means of a carbon paste electrode modified with 10% sepiolite using DPV. A 10 min preconcentration step was performed at pH 1.5 under open circuit conditions. Measurements were made in another cell by DPV with ΔE=100 mV (sweep rate = 40 mV/s) in 0.02 mol/l KNO3 medium at pH 2. Detection limits (3 σ) of 30 ng/ml were achieved for determinations in orange, lemon and cola drinks.
Keywords: Physical Chemistry; Analytical Chemistry; Phenol; Inorganic Chemistry; Detection Limit

Keywords: Physical Chemistry; Analytical Chemistry; Inorganic Chemistry; Clinical Application

New books (531-532).