This International Standard specifies an HPLC (high-performance liquid chromatography) method for determining the concentrations of cyclic oligomers of caprolactam, from 0,01 % by mass upwards, and linear oligomers of caprolactam, from 5 mg/kg upwards, both up to and including the hexamer of caprolactam (n = 6), in samples of polyamide 6, caprolactam and mixtures of rearrangement products in water. However, if there is a large excess of caprolactam (n = 1) relative to the cyclic dimer (n = 2), the latter cannot be determined quantitatively. For these cases, an alternative method is specified. This method uses HPLC to determine the concentrations of caprolactam and the cyclic dimer of caprolactam at concentrations of 0,01 % by mass and higher in samples of polyamide 6, caprolactam and mixtures of rearrangement products in water.
ISO 15033:2000 history
2018ISO 15033:2018 Plastics - Determination of caprolactam and its cyclic and linear oligomers by HPLC
2007ISO 15033:2007 Plastics - Determination of caprolactam and its cyclic and linear oligomers by HPLC
2000ISO 15033:2000 Plastics - Determination of caprolactam and its cyclic and linear oligomers by HPLC