Determination of Iodopropynyl Butylcarbamate and Zinc Pyrithione in Water-Borne Coating by High Performance Liquid Chromatography

The coating sample (about 2 g) was taken, ultrasonically extracted with 10 mL of N,N-dimethylformamide (DMF) for 10 min, cooled to room temperature, and centrifuged for 5 min. The supernatant was taken to a 50 mL-volumetric flask. The residue was ultrasonically extracted with 10 mL of acetonitrile for 10 min, and centrifuged for 5 min. After repeated twice, the supernatants were combined, and made its volume up to 50 mL with acetonitrile. The obtained solution was passed through 0.22 μm hydrophilic polytetrafluoroethylene (PTFE) filtration membrane, and separated on Agilent ZORBAX Eclipse Plus C₁₈ column, using a mixture of acetonitrile and 10 mmol·L^-1 potassium dihydrogen phosphate-1.0 mmol·L^-1 Na₂EDTA solution (pH 4.0) at a volume ratio of 7:3 as the mobile phase for isocratic elution. Iodopropynyl butylcarbamate (IPBC) and zinc pyrithione (ZPT) were determined by high performance liquid chromatography (HPLC), with detection wavelength of 235 nm. As shown by the results, linear ranges of the IPBC and ZPT standard curves were 20-2 000 mg·L^-1 and 50-800 mg·L^-1, with detection limits (3S/N) of 106, 298 mg·kg^-1, respectively. Test for recovery was made by the standard addition method, giving the results in the range of 92.4%-103%, with RSDs (n=6) of the determined values less than 3.0%. This method was used for the analysis of 4 actual samples, and ZPT was detected in only one indoor water-borne coating, with detection amount of 920 mg·kg^-1.