Investigations on adsorption potentiometry: Part IX. Determination of ultratrace boron by derivative adsorption chronopotentiometry

✍ Scribed by Wenrui Jin; Li Xiao; Yan Wu

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 442 KB
• Volume: 280
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(93)80243-e

✦ Synopsis

A derivative chronopotentiometric method for the determination of ultratrace boron, based on adsorptive accumulation of a boron complex on the surface of a hanging mercury drop electrode, was developed. In order to form the boron(liD complex with 4-[(4-diethylamino-2-hydroxyphenyl)azo]-5-hydroxynaphthalene-2,7-disulphonic acid (Beryllon III), it is necessary to boil the solution for 1 h and to leave it at room temperature for 20 h. The dependences of the peak value of the dr~dE vs. E curve for the reduction of the adsorbed boron(liD complex with Beryllon III on the preconcentration time, the preconcentration potential and the concentration of Beryllon Ill are discussed. The optimum supporting electrolyte is 0.05 tool 1-1 NaOAc+0.025 mol 1-1 HOAc, the optimum preconeentration potential is -0.30 V (vs. SCE) and the optimum concentration of Beryllon Ill is 500-5000 times the concentration of 13(II1). Under these optimum conditions, the detection limit is 8 × 10-12 mol 1-1 for a preconcentration time of 30 s. The relative standard error of the method is 2.4% for 4 × 10 -9 mol 1-1 B(III). The method was applied to food samples and the recovery was 98-103%.