WEBVTT

00:00:01.149 --> 00:00:04.150
Interactive numerical educational resources <br>for the analysis of complex media

00:00:05.759 --> 00:00:08.259
General information about gas chromatography

00:00:09.039 --> 00:00:09.990
In this video

00:00:10.410 --> 00:00:12.801
I will present a gas chromatography device

00:00:13.073 --> 00:00:14.563
In this device

00:00:14.583 --> 00:00:18.053
the different chemical constituents of a sample will flow in a gas stream

00:00:18.074 --> 00:00:21.623
which is the mobile phase and will be separated

00:00:21.654 --> 00:00:23.693
in the chromatographic system

00:00:23.740 --> 00:00:25.361
In gas chromatography

00:00:25.431 --> 00:00:27.451
one important component in the injector

00:00:27.460 --> 00:00:30.361
It allows to introduce the sample in the chromatographic column

00:00:30.478 --> 00:00:32.569
The samples could be gaseous or more

00:00:33.348 --> 00:00:35.918
generally they could be volatilized

00:00:36.192 --> 00:00:38.504
by reaching a high temperature

00:00:38.753 --> 00:00:43.084
In that case, the injector is warmed around 250°C

00:00:43.432 --> 00:00:46.582
so, obviously, for safety it is recommended to avoid touching it

00:00:46.603 --> 00:00:48.702
The liquid sample is introduced in the injector

00:00:48.756 --> 00:00:53.326
using a syringe equipped with a needle, which is here

00:00:53.646 --> 00:00:56.146
In the injector, the compounds are volatilized

00:00:56.156 --> 00:00:57.796
due to the high temperature

00:00:57.846 --> 00:01:00.369
Then, they are swept by the carrier gas

00:01:01.230 --> 00:01:03.920
through the chromatographic column

00:01:04.046 --> 00:01:06.465
The compounds are separated in this narrow tube

00:01:06.596 --> 00:01:11.204
The column is placed in an oven

00:01:12.378 --> 00:01:16.325
in order to separate the components

00:01:16.367 --> 00:01:19.665
according to their boiling point

00:01:20.189 --> 00:01:23.664
but also according to their interaction with the stationary phase

00:01:23.878 --> 00:01:28.808
the separated compounds will enter in the detector

00:01:29.490 --> 00:01:32.710
This device will record a signal proportional

00:01:32.721 --> 00:01:35.721
to the quantity of each separated molecule

00:01:36.012 --> 00:01:40.376
Then, you get a chromatogram on the computer

00:01:46.751 --> 00:01:51.453
which has been separated by the chromatographic system

00:01:40.653 --> 00:01:44.063
which is easy to recognize due to its chromatographic peaks

00:01:44.453 --> 00:01:46.383
The surface of one peak

00:01:51.653 --> 00:01:53.652
The analysis of this chromatogram

00:01:53.692 --> 00:01:55.852
will give information

00:01:56.822 --> 00:02:01.350
of each component of the sample by using the area of the different peaks

00:02:01.629 --> 00:02:04.490
Then, thanks to a more informative detector

00:02:04.698 --> 00:02:06.517
it is possible to get a spectrum

00:02:06.527 --> 00:02:08.633
which allows to identify the separated molecules

00:02:09.628 --> 00:02:12.903
General information about gas chromatography

00:02:14.900 --> 00:02:17.962
Interactive numerical educational resources <br>for the analysis of complex media