The problem of detecting gentamicin is one in which pharma has struggled with. Gentamicin does not absorb in the UV or visible region of the spectrum. In addition, derivatisation of the sample to enhance detection eliminates the subtle chemical differences between the four analogs making chromatographic separation impractical.
The MIC-9 Advanced IC system combines two important electrochemical detection methods: conductivity measurement and amperometric determination.
Conductivity measurement is accomplished when used with the 819 High-Performance Detector. Analyses of cations with electronic suppression or anions with chemical suppression down to the lower ppb range can be achieved.
For amperometric determination, the MIC-9 Advanced system incorporates a pulsed amperometric detector and isocratic elution on a polystyrene column. This does away with the quaternary gradient and derivatisation process prior to injection. This is a flexible system, with two channels, either in parallel or independently easily configured.
Thus the sample is injected directly into the chromatography system incorporating Metrohm Inline Sample Preparation technique (MISP) methods. Inline Filtration or Inline Dialysis is used for high loaded matrix samples.
MISP itself is a series of automated inline sample preparation methods especially developed for laboratory and online applications. These methods provide a means for rationalisation of time-consuming and cost-intensive manual sample preparation steps.
Sample preparation in IC includes all steps, which a sample has to undergo before injection into the ion chromatograph. This can be as easy as a dilution step or as complex as a clean-up using several types of solid phase extraction cartridges. This is usually expensive increasing analysis time and material cost.
Chemically, gentamicin is exceptionally stable, and is used extensively in animal husbandry. It can be stored at elevated temperatures for extended periods-of-time without loss of biological activity. Gentamicin occurs in four optically active analogs
The MIC-9 Advanced IC system is available now from Metrohm's website