What should I pay attention to when I use the gas chromatography instruments?

Gas chromatography instruments gas chromatography vials are like instruments from nurses in manual hospitals. Some can allow patients to complete an instruments without knowing it, while others can cause pain to the patient. The quality of the gas chromatographic instruments directly affects the results of the analysis. This article, Clecker, will come to analyze some of the problems that should be noted in gas chromatography instruments.

(1) Instruments speed. When the instruments speed is slow, the vaporization process of the sample is long, which causes the sample to enter the column to broaden the initial band. Therefore, it should be noted that the time taken to inject the sample and the time the syringe stays in the vaporization chamber should be properly controlled, and the more reproducible the process of each instruments, the better.

(2) Sampling is accurate and reproducible. That is, the sampling amount should be accurate, and the speed of sample extraction should be reproduced to ensure the reproducibility of the instruments. Especially for samples with high viscosity, avoid forming bubbles in the syringe.gas chromatography vials

(3) Avoid mutual interference between samples. If there is a residual component of the previous sample in the syringe during the instruments, it will interfere with the analysis of the next sample, resulting in a quantitative error. In the chromatogram, this is called the memory effect and must be eliminated. The usual practice is to wash the needle and wash the needle repeatedly with the sample solvent and sample.

Gas chromatograph autosampler

(4) Select the appropriate syringe. The most commonly used GC analysis is a 10 ul microsyringe, which is generally not less than 1 ul. If the instruments volume is to be controlled below 1 ul, a syringe of 5 ul or less should be used.gas chromatography vials

(5) Reduce instruments discrimination. The so-called instruments discrimination means that when the instruments needle is inserted into the GC inlet, the solvent in the needle tip and the volatile component in the sample first begin to vaporize. Regardless of the instruments speed, the components of different boiling points always have a difference in vaporization speed. If you can guarantee that the speed of each instruments is strictly the same (such as the autosampler), this discrimination can be ignored after standard calibration.