A spectrophotometric method for the determination of boron using azomethine H was studied and applied to the analysis of sea water, brine and bittern samples. Boron reacts with azomethine H at pH 4.5-5.8 to form a colored complex having absption maximum at 412 nm, which canb e used for the determination of boron. Beer's law is obeyed up to the concentration of 30μg/25 ml of boron. The apparent molar absorptivity of the complex is 8,300lmol^-1cm^-1 at 412 nm. Some metal ions interfering determination of boron with azomethine H can be effectively masked by EDTA and can be tolerated without further separation. When known amounts of boron wasadded to the sea water samples, the boron was recovered satisfactorily.
Boron content in sea water samples was estimated to be 4.15-4.76mg/liter, and that in brine and bittern samples produced by the ion-exchange membrane method to be respectively 2.67-3.13mg/liter and 53.9-64.1mg/liter. Boron content in those samples produced by the salt-field method was much greater.