DOOB reagent

Note The reagent can be employed for qualitative and quantitative analysis on silica gel and RP layers. Ammonia, amine and acid-containing mobile phases should be completely removed beforehand. Amino phases cannot be employed. The NBD-chloride reagent is not as sensitive as the DOOB reagent (qv.) on RP phases. 

DBA solutions should only be stored for a short time even in the refrigerator. On the other hand, DOOB reagent solution in bottles with ground-glass stoppers may be stored in the refrigerator for at least 2 weeks. 

The DOOB reagent, which is formed by reaction of diphenylboric anhydride with salicylaldehyde, yields fluorescent reaction products with primary amines [1]. 

Note If netilmicin is to be chromatographed alone it is recommended that the methanol content of the mobile phase be increased (e.g. to 23 -I- 7), in order to increase the value of the hRf. The detection limit for the substances in the application tested was more sensitive using DOOB reagent on RP layers than when NBD chloride, fluorescamine or o-phthalaldehyde were employed. The derivatives so formed were stable and still fluoresced after several weeks if they were stored in the dark. 

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