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of penicillin G [160,161] in dairy products such as milk, cheese and yogurt, and cloxacillin [162] in
bovine tissues followed by separation with reversed-phase HPLC and detection at UV 325 nm after
SPE (Bond Elute C18) clean-up. The detection limit of this method was 3-5 ppb. The precolumn
method with formaldehyde/trichloroacetic acid was another fluorescence derivatization and applied for
the analysis of amoxicillin [163] in catfish and salmon (Fig. 1.2.9) and ampicillin [164] in bovine milk.
Fluorescent derivatives with this reagent were assumed to be 2-hydroxy-3-phenol-6-methylpyrazine for
amoxicillin (Fig. 1.2.10) and 2-hydroxy-3-phenyl-6-methylpyrazine for ampicillin. These detection
limits were 0.31-0.8 ppb, and this method has achieved enhanced sensitivity and detectability compared
with 1,2,4-triazole/mercuric chloride in UV detection.

Aminoglycoside Antibiotics

Streptomycin (SM) and dihydrostreptomycin (DSM), representative aminoglycoside antibiotics, form
the streptamine group of aminoglycoside antibiotics that consist of a disaccharide molecule with a
streptidine (diguano derivative)

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