Dear All,

The only experience I have in urine analysis is the assay of Urine Catacholamine, and we put in boric acid for preservative. However, I would need to collect samples for a drug (antibiotic) levofloxacin. The method has been established, but do I have to put in preservative(to avoid drug degradation) for the urine collection (i.e. boric acid, etc.)? Or do I just collect the urine and store it at -70 degrees before analysis?

I have been looking at literatures and could not find any information. Please give me some insight.

Thank you all for your help!

We are analysing drugs in urine for years. We never used any preservatives for that purpose, and it is generally not recommended, too.

For validation purposes you should spike some urine-samples and watch degradation.
Boric acid itself is definitely useless for other substances, because it forms a complex with catecholamines, thus keeping them stable. Try HCl instead.