Analytical and Bioanalytical Chemistry (v.333, #3)

The combination of SIMS, electrical resistance measurements and TEM was used for investigation of “high concentration effects” of Sb and P in silicon. For antimony implantation and annealing combined with and without preannealing were studied. The distributions and the precipitated fraction were determined by SIMS. TEM investigations showed that by preannealing at a temperature of 1150°C no dislocations but only precipitates are formed. Thus the precipitation kinetics for an isothermal case (1000°C) could be studied. The size distributions of precipitates were determined by image processing of plan view TEM micrographs. The kinetics of the precipitation process was simulated for the distribution function by a computer model and compared with experiments. A good agreement between experiment and simulation was obtained.For phosphorus, specimens implanted with medium and high doses were investigated. With medium doses small extrinsic dislocation loops (size 20–40 nm) were observed near the amorphous/cristalline boundary. The dislocation loops are formed by agglomeration of interstitial silicon atoms which are supersatured in the long range of the implantation profile.The coupled diffusion of high doses of P and low doses of Sb and B was studied. In the SIMS distributions enrichments of boron were observed. TEM measurements showed that they were correlating to a severe band of defects.SiP precipitates and large perfect dislocation half loops [mean radius (195±112) nm] were observed after annealing at 900°C for 120 min of implants with a dose of 5×1016 cm−2 P. Because precipitation is occurring, simulation of phosphorus diffusion is at present not possible.

The concentration of some additional elements like Ag, Au, B, Ba, Be, Co, Li, Mo, Na, P, Pt, and S in some standard reference materials (SRM's) were determined by using high resolution ICP (Inductively Coupled Plasma)-emission spectrometry. The materials used were three soils and three sludges from the BCR (Community Bureau of Reference, European Communities) and one sediment from NBS (National Bureau of Standards, USA). The aqua regia soluble and the total content using HF-treatment were shown. The given results are the mean values of 6 independent measurements for each material and for each decomposition method (certification conditions). The quantitative determination of Au and Pt was not possible due to severe spectroscopic interferences, which could not be eliminated. Beside the concentration values also the measured detection limits and the limits of determination for each element in the matrices under investigation are given. For comparison and for testing the validity of the decomposition procedures, also certified elements like Cd, Cu, Ni and Zn have been analysed in all the samples.

High resolution gas chromatography with electron capture- and mass selective detection was used for the characterization of the constituents of the technical cyclodiene pesticide chlordane. Degradation reactions were used for confirmation of tentatively identified chlordane components in environmental samples. The pattern of chlordane congeners in cod liver from Norway is described. Compared to the technical product the nonachloro congeners are unchanged in their relative occurrence. Among the octachloro congeners, trans-chlordane is diminished relative to the cis-chlordane.

The electrochemical behaviour of the herbicide 4-amino-3-methyl-6-phenyl-1,2,4 triazine-5(4H)-on (Metamitron) is studied in aqueous medium using voltammetric techniques, with the ionic strength adjusted to 0.1 mol/l in sodium perchlorate and using a Britton-Robinson buffer. Two reduction waves on the mercury drop electrode appear, at −0.49 V the first and the second folded at −0.95 V and −1.05 V. The system is identified as irreversible and fundamentally controlled by diffusion. Using differential pulse polarography the detection limit reached was 0.02 mg · l−1 for the first wave with an error of less than 2%. Thus a method is proposed for the determination of Metamitron in soil, with a detection limit of up to 0.02 μg/g.

A gas-chromatographic method for the determination of the total organic fraction (TOF) present in the total particulate matter (TPM) of mine aerosols and the analysis of this fraction by gas chromatography — mass spectrometry is presented. The method is statistically evaluated and the standard deviation is calculated. The method for the determination of TOF was checked by a series of analyses of TPM in an iron-ore mine and in a deep mine for magnesite.

A tubular solid-state lead(II)-selective electrode was prepared and constructed as a compact tubular sensor (volume 8.8 μl) from a lead tube and Tygon tubing. The lead/ lead sulphide membrane was activated by anodic deposition and conditioned in lead nitrate medium at pH 3. The incorporation, behaviour and suitability of the coated tubular electrode into the conduits of a continuous flow system and a flow-injection system was evaluated and is described. The performance of the tubular lead sensor in the FIA system is satisfactory. With 30-μl samples injected into the FIA system, the flow-through electrode responded quite well for lead(II) concentrations of 250 mg/l upwards at a sample rate of about 40 per hour. Interferences in aqueous solutions are described.

New books by Cz. (231-233).

2.6 Foods (263-265).