Problems and improvements of the regulated analyses method on GC for nonyl phenol isomers

Abstract

We report problems and improvements of a regulated analytical GC method supported by ISO/DIS 24293 for nonyl phenol isomers (NPs). The variations of peak area and recovery of NPs were found on a regulated GC method which 4-n-nonyl phenol-2,3,5,6-d4 (4-np-d) and phenanthrene-d10 (fnt-d) were utilized as surrogate compounds with syringe spiking. Furthermore, we investigated the relative recovery by the continuous injection of NPs, 4-np-d, and fnt-d, then the decrease rate of peak area of each compound was different although all peaks were gradually decreased. Consequently, the decrease rates of NPs and 4-np-d were higher, and the relative recovery of NPs were also decreased. After cutting off the GC column (about 50 cm) and replacement of an injection insert, the peak areas of compounds were completely recovered. Therefore, we anticipate that the problem was caused by adsorption or degradation of NPs in the inlet area. Additionally, a similar decrease of peak area was observed on the pretreated real samples by the effect of matrix.