Generally, when operators use gas chromatograph first time, they do not know how to configure chromatographic column reasonably. They always want more chromatographic columns because they believe the more columns bring the better. Then, they blindly purchase many columns, stationary liquid or supporters etc., which results in lots of laid-up and waste. Here, we recommended some useful tips as follows:

Based on many years of experience, generally, several columns can meet all kinds of requirements of gas chromatographic analytical work. The preferred columns which stationary liquid are SE-30, OV-101, OV-17, PEG-20M, DEGS and FFAP. For packed column, the supporter could be white supporter, red supporter, GDX series and Porapak series. Aboves may basically satisfy majority of working requirements.

Selection of column length: The resolution is proportional to the square root of column length. The longer column, the better resolution. Generally, 15m short column is used for fast separating simple sample; it is also suitable for composition analysis. 30m chromatographic column is the most common one. Most analysis are carried out on 30m column. 50m, 60m or even longer column is used for separating complicated sample.

Selection of column size: Size of column directly affects the efficiency of column, retention characteristics and sample capacity. The efficiency of small size column is higher than big size column, but the capacity of small size column is less than big size column.

0.25mm column size: Higher column efficiency, lower column capacity. Better performance for analyzing complicated sample.

0.32mm column size: Column efficiency is slightly lower than 0.25mm chromatographic column. But, column capacity is about 60% higher than 0.25mm chromatographic column.

0.53mm column size: Column capacity is similar to the capacity of packed column. It is suitable for both split sampling and splitless sampling. When column capacity is the main consideration factor during analyzing (for instance, trace analysis), it is better to choose big size capillary column. For ordinary user, 30m or 50m length capillary column with 0.32mm size is economical and practical.