[The use of feed medications in swine and poultry facilities in the Weser-Ems region]. / Zum Einsatz von Fütterungsarzneimitteln in Schweine- und Geflügelbeständen in der Region Weser-Ems.

The use of medicated feed notably in large pig and poultry holdings is a major aspect of veterinary treatment against infectious diseases. Every single production of a medicated feed requires a specified written authorization by the veterinary practitioner and a carbon copy of this document must be sent to the responsible veterinary public health office. These documents-in the Weser-Ems region up to ca. 30,000 per annum-were entered into a computer database and analysed. The results are presented as diagrams and graphs. Information on the quantities of the various administered drug constituents is also included. With regard to current risks concerning residues and resistances the data gives qualified information on the per os treatment with antibiotics of food producing animals.

[Ion chromatographic analysis of cations and anions in mineral water]. / Ionen-chromatographische Analyse von Kationen und Anionen in Mineralwässern.

For the simultaneous analysis of the cations Li, Na, K, Ca, and Mg as well as Mn and the anions hydrogen carbonate, chloride, sulfate and nitrate, silica gel- and polymer-based ion exchange materials with conductivity and spectrophotometric detection combined with a post-column derivatization system (PAR-Zn-EDTA for Ca, Mg, Mn) and also an ion-pair system with RP-18 phase were compared with a view to their application to mineral water samples. It is possible to determine Li, Na, and K in such samples with or without the suppressor technique using polymer columns. A polybutadiene maleic acid silica gel cation exchanger material makes feasible simultaneous analysis of alkaline and earth alkaline metals. Ca, Mg, and hydrogen carbonate, chloride, sulfate and nitrate are analyzed in less than 16 min using a silica gel anion exchanger with EDTA as the eluent. To stay within the linear range of the calibration function it is necessary to perform two injections in different dilutions (between 1:4 and 1:500) due to the different concentration ratios. For the analysis of manganese above 100 micrograms/L a system with the cation exchanger Partisil SCX and the eluent ethylenediamine/oxalate with post-column derivatization is used. The sample pretreatment is done by reduction with thiosulfate. A total of 15 different mineral waters were analyzed with all the systems and the results were compared with those of reference methods (AAS, potentiometry), showing good conformity.