2011 Volume 97 Issue 2 Pages 65-69
The size of the blank value is enumerated in one of the factor that influence the detection limit in the fluorescence determination method. The blank value in this case is brought about by excess reagent. Therefore, the some methods for removing the excess reagent were studied under the conditions of the stability of boron-complex. To remove the influence of excess reagent, the solvent–extraction method etc. is used beside a method of changing the pH. This study attempted a fluorescence determination of boron by flow injection analysis using the methanol as a carrier liquid. As a result, the amount of reagent decreased down to 1/15 compared to that of conventional method, because of decreasing the amount of water in the sample solution.
The water in the sample solution suppressed the reaction between boron and 2,3-dihydroxynaphthalene (2,3-DHN). Therefore, the decrease of water tolerates the low concentration of 2,3-DHN. Under the optimum conditions, a calibration curve was drawn, which was linear over the range of 0 to 120 ppb. The relative standard deviation at 20 ppb B was 0.9% (n=6). For the determination of a trace amount of boron in steels, the on-line separation/preconcentration of boron from iron matrix (500 ppm) was performed by using resin (Amberlite IRA 743). The limit of B determination was 0.8 ppb (1.5 ppm in steels). The determination results for boron in standard steel materials showed good agreement with the certified values.
