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min, then quenched with 4.5 ml water. After the reaction, the mixture was purified by C18 cartridge and
centrifugation at 9000 g, the benzoyl derivatives were subject to RP-HPLC. Gradient elution using
acetonitrile and water was performed and the separation of derivatives was monitored at 230 nm. Using
this method, Dglucose, 1,6-anhydro-L-idose and D-galactosamine were separated within 60 min. The
detection limit was 10 ng (S/N = 2), and the calibration range was 0.05-4.0 µg.

2.4.3—
Isocyanates

Isocyanates are also used for the derivatization of hydroxyl group. They react by nucleophilic addition
to form carbamate derivatives. For ultraviolet detection, phenylisocyanate is widely used and the
resultant phenylcarbamate is a stable, UV absorbing compound (230-240 nm). The reaction is shown in
Fig. 2.33. Indyk et al. [123] reported a simple method to determine myo-inositol in infant formulation,
which is based on cow's milk. Inositol was derivatized with phenylisocyanate and separated by C18

Fig. 2.33.
The reaction of hydroxyl group and phenylisocyanate.

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