Table 3.

Comparison of MAD with other methods for determining VPA in human plasma.

Derivatizing agent	Reaction time	Heating conditiona	Linearb (μg/mL)	Recovery (%)	references
Non-derivatization	–	–	10–150	94.3c	[38]
Conventional method derivatization
4-brophenacyl bromide	15 min	70 °C,	274–372d	95–100	[47]
O-p-Nitrobenzyl-N, N′ diisopropylisourea	1.5 h	80 °C,	50–100	97.7c	[23]
para-bromophenacyl bromide	1 h	70 °C	10–150	25.02 ± 1.5c	[24]
2,4′-dibromoacetophenone	45 min	55 °C	1.0–200.7	91.6–97.4	[27]
Microwave-assisted derivatization (MAD)
Phenylhydrazine hydrochloride	50 s	450 W	30–150	86.7–107	This work

^aThe water bath's heating was indicated by temperature, whereas the microwave's heating was indicated by power.

^bThe valproic acid concentration in the plasma/serum.

^cThe value was calculated from average percent recovery.

^dThe unit was μmol/L.