Analytical HPLC methods are highly sensitive and play an important role in the laboratories of the pharmaceutical industry, in contract laboratories specializing in environmental analytics, in purity checking and monitoring of industrial products and fine chemicals and also in university laboratories. They make it possible to identify and quantify even small amounts of trace substances. This occurs, for example, in the determination of the purity of drugs and their active agents during quality control.
With the aid of high pressure liquid chromatography, or HPLC for short, it is possible to chromatographically separate substances in solution. To protect the chromatography columns, manufacturers recommend the filtration of samples and mobile phases to prevent particles from entering the packed columns and thus changing their separation properties. In order to preserve the integrity of the sample, the filter material being used must not give up extractable components to the sample and must not adsorb constituents of the sample.
Aluminum oxide ceramic membranes are free from organic "Extractables and Leachables". The fragile membranes have two different sides. The upper side of the membrane possesses large-diameter pores whose diameter remains constant along their length. The effective filtration barrier is created on the underside of the membrane by the smaller diameter of the pore openings. The relationship between the different pore sizes increases the reliability of the results, particularly in the trace substance analysis of unknown substances and in quality control by pharmaceutical, chemical and food companies.