engleski

Densitometric determination of metals in alloys

Alloys are designed to optimize certain technical properties, such as mechanical strength, workability, wear and corrosion. If the metal objects involved are unique in nature (e.g., statues, utility objects of different shapes and sizes in alloy), it is often necessary to sample with minor or even without destruction. There are only few methods of chemical analysis known to satisfy these conditions. External beam proton induced X-ray emission spectrometry (PIXE) and X-ray fluorescent (XRF) analysis are nondestructive methods for in situ measurements, but they require sophisticated and expensive equipment. [1] The advantage of nondestructive methods is the possibility to measure a larger number of surface samples taken at various positions on the object. In this work anodic sampling hyphenated with thin-layer chromatography was used with videoimaging system for archiving and processing of chromatograms. Hence, the influence of instrumental settings of a video-imaging system on quality of captured images has been studied. Performances of the CAMAG Video Documentation System were evaluated by the measurements of absorption quenching for model standard solutions of metal ions of copper, tin and nickel in visible (VIS) spectral region. The effects of different camera settings (aperture and number of accumulated frames) on the background response, baseline noise and reproducibility of detection were studied on commercial cellulose TLC plates. [2] The results showed that as the number of frames, the image brightness and background response increased, the sensitivity increased too. Plates captured and illuminated from up and both modes gave more repeatable results. Repeatability of determination (RSD) was ranged from 9, 2-32, 3% for copper ions, 10, 9-52, 2% for tin ions and 8, 8-56, 4% for nickel ions.

thin-layer chromatography; video-densitometry; copper; tin; nickel

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