A DETERMINATION OF BORON BY SPECTROPHOTOMETRY

1 Borate ions form a red coloured compound with Azomethine-H at pH 4-5. The absorbance of the complex is measured at a wavelength of 430 nm. 

2 This determination may be earned out on digest 2.8 (digestion by dry-ashing in the presence of CaO). 

1 This procedure yields a standard cunre that is linear up to approximately 2 mg/L B. 

2 The detection limit is approximately 0.1 mg/L in the digest. The determination limit is approximately 0.3 mg/L (3 mg/kg dried plant material). 

1 The reproducibility of determinations by this procedure should give, at reasonable control and thorough sample preparation, a coefficient of variation within 10 %. 

---