The Effect Of Assuming The Hold-up Time On The Prediction Of Retention Time Under The Vatiation Of Capillary Column Film Thickness In GC

Retention time is an important qualitative index for determining the effect of temperature programmed gas chromatography separation.It can quickly determine the best separation conditions,thus it can improve the separation efficiency.In the process of predicting the retention time,the hold-up time is essential.Traditional measurement methods for obtaining the hold-up time must be based on the experimental measurements,which will increase the complexity of the study and reduce the efficiency.When predicting the retention time,all the factors including length of the column,flow,pressure,temperature change,researchers need to re-determine the basic data.It increase the workload of the study.So this paper propose a novel method assuming the arbitrary hold-up time,defined as less than the minimum of the real retention time,was described to predict retention times in capillary gas chromatography.And it introduce the concept of the correcting hold-up time.In this paper,the study compared the average absolute relative errors of six arbitrary hold-up times(1.85 min,1.5 min,1 min,0.5 min,0.1 min and 0.01 min)to predict retention time across 20 analytes during chromatographic separations with temperature programs(three single-ramp and three multi-ramp).The average absolute error of the time under six arbitrary values is no more than 0.1%.Then we use the method of dynamic coating to coat the two capillary chromatographic column,and observed by scanning electron microscope(SEM).At last,determinating the retention times of 16 compounds under the 6 constant temperature conditions,the 3 single-temperature programmed conditions and the 3 multi-temperature programmed conditions,then we use those basic data to predict the retention time reciprocal.The results show that the prediction of the retention time of the column 1 and column 2 can be predicted by the correcting hold-up time,which can greatly reduce the experimental data and using this method simplify the prediction of the retention time.