General Information

We investigate the elemental composition of samples - organic as well as inorganic material, chemically pure substances and technical products - determining their contents of C, H, N, S, O, F, Cl, Br, I and P requiring minimum substance amounts (2 to 10 mg per analysis). We also have methods available to run TOC (Total Organic Carbon content) in solid materials, AOX and POX according to DIN 38.409 H 14. Some methods for ion analysis using CIE (Capillary Ion Electrophoresis) are ready to use and we are able to develop methods for special requests.

We can offer our services to academic institutions as well as firms and private persons.

Our laboratory is primarily dedicated to perform the C/H/N elemental analysis required by the University of Vienna's chemistry and pharmacy institutes and other Austrian academic institutions performing preparative chemistry. Our equipment enables us to run C/H/N/S analysis, to determine the content of halogenes, phophorus and oxygen. All services are offered against charge. Accounts are within Austrian University Law's "Teilrechtsfähigkeit" which besides others means that there is no sales tax included.

All methods are adjusted for sample amounts of 2 to 10 mg and perform with an uncertainty within 0,3 w-% as required by literature for confirmation of assumed chemical composition. The operation range covers the content from 100 to 0,1 w-% and can be extended to 0,01 w-% under certain conditions.

Besides our routine services we are dealing with method development.

During the last few years we could achieve a significant improvement in halogene determination. Since 1996 we are working on the implementation of ion analysis using Capillary Ion Electrophoresis (CIE, web page still in German). Based on this technique we were able to improve the speed and performance of halogene and sulfur determination in the concentration range of 1,0 down to at 0,01 w-% (and probably even lower).

History of the Microanalytical Laboratory of the University Vienna

The Microanalytical Laboratory has come to be a rather ancient institution. Founded within the 1930s to make the techniques of micro elemental analysis in organic chemistry introduced by Pregl accessible to the Viennese chemistry institutes. In 1923 Prof. Fritz Pregl had been granted Nobel prize for his scientific work of developing methods for elemental analysis requiring mimimum sample amounts. His laboratory in Graz/Styria/Austria had been world famous for many years.

First the techniques introduced by Pregl had been used by individual preparatively working chemists to confirm their own results. Hermann Mark as head of the I^st Chemical Institute of the University Vienna (1932 - 1938) assigned some rooms to found a central laboratory for microanalytical chemistry. Ludwig Ebert, head of the institute since 1946, expanded the laboratory. Additional room was dedicated to the laboratory by Hans Nowotny (around 1960). Since the reorganization of the chemistry insitutes at the University Vienna in 1958 the Microanalytical Laboratory belongs to the Institute of Physical Chemistry. The laboratory is still situated around the location where it all had started.

Dr. Kurt Horeischy, who had become famous within the chronics of University Vienna by his death during the last days of World War II was one of the first heads of the "Microchemical Laboratory" (1941 to 1944).

Since 1945 Bühler was head of the laboratory. He emigrated to USA in 1948. He was followed by Wagner who moved to Ciba-Geigy/Basel/Swiss in 1951 and Padowetz who later was also emploeyed by Ciba-Geigy. In 1956 Dr. Josef Zak was charged head of the "Microanalytical Laboratory". He had become a synonym for elemental analysis all over Austria. Since 1989 the laboratory is run by Johannes Theiner.

During the last several years method development has come to be the minor part of duties as the techniques of C/H/N analysis have been well established before.

In 1989/90 the method for Cl/Br determination could be improved by introduction of potentiometric titration replacing the former method of colorimetric titration according to Mohr. The introduction of CIE (Capillary Ione Electrophoresis) as a detection method offered a significant decrease of the determination limit without increase of sample amount investigated. This method is still under investigation and is to be validated in the sence of modern quality insurance.

The Microanalytical Laboratory almost holds a monopoly on organic micro elemental analysis within Austria. As the necessary tools have been available for many years there is not much scientific interest in further development of this branch of analytical chemistry. Statements concluded from the characterization of the main constituents are hardly relevant in the fields of environmental and pharmaceutical chemistry. Nevertheless these data are still an essential criterion to confirm the composition in preparative chemistry prior to a publication in most journals.

Experience confirms the following theoretical considerations:

Each method used to characerize a substance has its value

Chemists use to rely on the patterns found using NMR spectroscopy. As this investigation is done using a solution of the substance under test insoluble contaminations cannot be seen at all. Besides that many compounds do not show a ¹H or ¹³C NMR spectrum at all. Similar restrictions can be concluded for all spectroscopic techniques.

If Mass Spectrometry is used for structure confirmation evaporization and ionization of impure samples=mixtures tend to be affected by fractioning according to volatility. So many possible contaminations cannot be identified in a mass spectrum.

Elemental analysis really is a quantitative method. The concentration of each investigated element can be evaluated with regard to the weighed in sample amount. Experimental techniques provide an uncertainty as low as the 0,3 w-% required by journals. Inorganic impurities and components with high fraction of hetero elements are easily indicated (e.g. halogenated solvents as CH₂Cl₂). By the way it must be concerned that 100 % effective mineralization can fail for a class of compounds.