Mid-polarity SP columns are rarely used to analyze UDMH transformation products, but midpolar columns (DB-1701) were used to analyze N-nitrosodimethylamine . There are also very few data on RIs for mid-polarity SP, which makes columns with this phase an interesting object for such studies. Based on our results, we can conclude that the mid-polar column (DB-1701) has the best separating ability in relation to a complex mixture of UDMH transformation products. Thus, substances such as 3-amino-1,2,4-triazole and 4-amino-4H-1,2,4-triazole, which had blurred chromatographic profiles on HP-INNOWax and RTx-5MS, came out with good chromatographic peaks on DB-1701 (Figure ). Figure shows the chromatogram of one of the selected mixtures of the target analytes with a mixture of alkanes. In Table , the results of calculation and prediction of retention indices for the studied compounds are shown. shows that the predicted RIs for the selected analytes correlated well with the experimental data, which we did not predict. The better convergence for the RIs for the mid-polar SP compared to the polar stationary phase can probably be explained by the fact that for this SP there are fewer RIs values and therefore fewer erroneous values. Also, for 4-amino-4H-1,2,4-triazole, the largest discrepancy between the RI and the experimental one is observed for the nonpolar and polar phases as well.