The determination of isomers of dihydroxybenzenes by high performance liquid chromatography with chemiluminescent detection

Based on the inhibition by hydroquinone, catechol and resorcinol of chemilu minescence from luminol-potassium hexacyanoferrate(III) system, a high perf ormance liquid chromatographic procedure with chemiluminescent detection wa s developed for simultaneous determination of hydroquinone, catechol and re sorcinol. The separation was carried out on RP-C-18 column at 37 degrees C by using a step gradient elution made by the mobile phases of methanol(A) a nd 0. 05% H3PO4 (B), The gradient elution condition was 95% B, 5 min; 95%B- 50%B, 1 min; 50% B, 6 min, This method has the merits of high senstivity an d good selectivity. The detection limits for hydroquinone, catechol and res orcinol are 2. 0 x 10(-9), 3. 2 x 10(-9) and 6. 8 x 10(-7) g/mL, respective ly, The relative standard deviation(n = 5) is 1. 9% for 2. 5 x 10(-7) g/mL hydroquinone, 1. 0% for 7. 5 x 10(-7) g/mL catechol, 4. 0% for 5. 0 x 10(-5 ) g/mL resorcinol, respectively. The recovery is in the range of 94%-104%.