• Analytical Science and Technology
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• v.7 no.2
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• pp.173-179
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• 1994

The point of present study was focused on developing the method for the determination of dissociation constant by means of FIA conjunction with Diode Array Spectrphotometry or spectrophotometry along with small amount of Bromocresol Green(mg order) within short time. On the calculation with computer, the indicator with pK=7 has been shown the most sensitive reaction when little amount of base or acid has been added. The pKa of Bromothymol Blue and Bromocresol Green were measured as 7.31 and 4.82 respectively with spectrophotometry after activity correction by Kielland method (Reported value by Bishop, 7.30 and 4.79). The pKa of Bromocresol Green by FIA was obtained as 4.78 and was comparable with other values determined by other methods.