Analytical method of IPBC by HPLC and leachability in treated wood and bamboo

  Objective  In order to explore the leachability of iodopropynyl butylcarbamate (IPBC) formulations, an analytical method of IPBC by high performance liquid chromatography (HPLC) was established and used for the determination of IPBC leaching rate of treated wood and bamboo, aiming to determine an analytical method of IPBC by HPLC and the leachability of IPBC.

  Method  UV detector and C₁₈ column (150 mm × 4.6 mm (inner diameter), 5 μm) were used for detection. The chromatographic conditions, such as detection wavelength, mobile phase composition and ratio, column temperature and mobile phase flow rate were investigated and discussed, so as to optimize the chromatographic conditions suitable for the analysis of IPBC. The IPBC standard solution was detected by external standard method. The standard curve, precision and accuracy were evaluated. The leaching procedure was adopted according to the Chinese standard method. The IPBC leachability rate was tested in treated wood and bamboo by the established analytical method.

  Result  The chromatographic conditions for the determination of IPBC content by HPLC were as follows: flow phase acetonitrile-water (60∶40), flow rate 1.0 mL/min, UV detection wavelength 200 nm. There was a good linear relationship between IPBC concentration and chromatographic peak area in the range of 5−80 mg/L for IPBC standard solution. The correlation coefficient was r = 0.999 4. The standard deviation and coefficient of variation were 0.05% and 0.50%, respectively. The recovery rates were 99.5%−100.4%. The leaching rate of IPBC in Masson pine and radiation pine decreased with the increase of IPBC concentration, the leaching rate of Masson pine ranged from 0.11% to 1.99%, the leaching rate of radiation pine ranged from 0.10% to 0.48%. In bamboo, the leaching rate of IPBC increased with the increase of IPBC concentration, with the leaching rate ranged from 3.11% to 7.08%. The average leaching rate of IPBC treated bamboo was higher than IPBC/PPZ-TEB. The leaching rate of IPBC micro emulsion in treated wood was higher than that dissolved with ethanol. The leaching rate of IPBC with surface coating of hard wax oil in treated wood was lower than that without surface coating.

  Conclusion  The determination method of IPBC content by HPLC with good correlation, high precision and recovery rate could be used for the analysis of IPBC content. The leaching rates of IPBC treated masson pine, radiant pine and bamboo were very low as less than 7.1%. The leaching rate of IPBC could be decreased by mixing with other agents or surface coating with hard wax oil.