An example of detector adjustment of the hottest g

2022-07-30
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An example of gas chromatograph detector adjustment

our laboratory has a hp5890 gas chromatograph (machine a), equipped with FID, ECD, single packed column inlet, gas sampling valve, and another HP gas chromatography-mass spectrometry (machine B). MSD has been broken and unused for many years, but its FID is used only, and the double split sample inlet is not split

the two machines were originally purchased by different departments. Later, after the combination of analytical instruments, machine a was mainly used to make air samples because of its gas sampling valve, but only FID was used, and ECD was idle for a long time. The MSD of machine B broke down many years ago. My plan is as follows: install the ECD of machine a on machine B, so that we can make use of the shunting and non shunting injection port of machine B, and then connect the capillary column for analysis, which provides more means. (there are ECDs on other aircraft, but there are often sample conflicts, and there is always a feeling that they are not enough)

my steps are as follows:

1. remove the ECD on machine a

open the side plate and pull out the signal card. Then loosen all the screws on ECD (if there is a column, remove it first). E if the swing rod does not stop at the middle position, there are three types of CD cover, base and main parts. There are two things on the main part that should be carefully pulled out, one is the heating rod, the other is the temperature measuring rod, especially the latter, which is easy to break. Connect two groups of wires to the back of the heating and temperature control unit, disassemble the rear board of the instrument, pull the two wires to the right side of the instrument while removing them, and set the position of the welding spot on the connector on the main board where the signal wire is inserted. All four wires should be recorded

2. find out the temperature control line on machine B

det on B machine. A is FID and det. The temperature of B refers to that the heating of mass spectrum interface mainly adopts the method of multi-point grounding bushing (I think it is common for a module). Disassemble the side plate of machine B and connect it with the det of machine a. B's four wires were viewed on the welding spot (I didn't bother to read the manual, so I used the instrument to look at it accordingly). As expected, the four wires extended to the leftmost side of the machine, that is, the MSD end, and the designs and colors were also different. All the way down, the 5971 heating sleeve was finally removed. First, the white sleeve was pulled out. There were two aluminum blocks screwed on the iron pipe, and the screws were all rusted., The temperature control unit inside can only be found when it is completely disassembled. Sure enough, it is also heated and measured one by one. However, its size is completely different from that of ECD. The original cable can only be damaged and connected another

3. install ECD on machine B

open det. For the plate at position B, use a paper cutter to cut the position that can accommodate the ECD base (there is a backward turning action during installation, so it is necessary to cut an extra centimeter). Install the base, tighten two screws, and then insert the signal card from the side plate. A bayonet on the ECD main part is tightly sleeved at the receiving end of the signal card. Then cover the ECD and tighten all the screws (note that there is also a small cover plate covering the quartz cotton, and do not forget to install it)

connected to det of machine a. The four temperature control wires of machine B are cut off (leaving enough length and sealing the port), the rubber is stripped, the metal wire is exposed, and then connected to the temperature control wire of the heating sleeve of the original MS interface of machine B (to be welded). Since the temperature control group wire of machine B is connected by the signal interface near MSD, it is only necessary to remove this joint for welding, so as not to cause another breakpoint

press the wire into the trunking and cover other side plates

4. After other

are installed, pay attention to plugging the original gap. For example, after the ECD of unit a is removed, it is not just a matter of adding a plate on it. There is also a hole at the lower column temperature box. If it is not sealed, the adjacent det will be damaged. A there is an impact, so the hole below should be sealed, filled with quartz cotton, and then covered with the original cover plate. Similarly, after the 5971msd of unit B is removed, there is also a hole on the left side of the incubator, which should also be carefully blocked

hp5890 is equipped with dual detectors as standard, so the signal cards of detectors are installed in their current positions. The main problem is that the temperature control line group will be troublesome if the original connector position is not available

however, the installation of ECD does not involve the problem of air circuit, which saves a lot of work

the joint is welded by an electrician. I'm not sure if the welding is too thin. Generally, I can get good low VOC products. I'm not sure about small things. All the others are disassembled and assembled by myself, which saves the unit a lot of money since it has entered the adjustment period

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