What is the column in your instrument?

He is too expensive. Ar can be used as carrier gas to detect hydrogen and oxygen by water splitting. TCD detector, MS-5A columns, and argon carrier gas, carrier gas flow rate: 30 mL/min, column temperature: 30 °C, TCD oven temperature: 100 °C, bridge current: 80 mA

Dear Prof. Yurii V Geletii , I use Packed column, serial number : C47839-04. Shin Carbon ST 100/120, 2m 1 mmID 1/16"OD Silco, Made in USA from RESTEK. Thank you..

Dear Prof. Yukun Zhu . Thank you for your suggestion. However, how to change the gas carrier to Ar gas by using GC 7890B? I try to look at the software, there is no selection for Ar option in TCD in configuration menu.

In the configuration menu,

there are some configurations,

1. Front inelt, SS inelt : He, N2, H2, Ar/Me

2. Back inelt, PP inelt : He, N2, H2, A/Me

3. Front detector, FID, make up : He, N2, H2

4. Back detector, TCD, make up/reference : He, N2, H2

I attach the photo of configuration menu in this response.

Thank you

We no longer use packed columns. Follow Yukun's recommendations and read the manuels .

Thank you Prof Yurii V Geletii ...

Sorry, I have not used this software, you can consult the equipment engineer.

I have used N2 as the carrier gas and was able to detect both H2 and O2. Both Hydrogen and oxygen can be detected with nitrogen as the carrier gas. If Nitrogen is used as the carrier gas, Since the response is directly propotional to the themal conductivity difference of the gas and Nitrogen ( carrier gas). In such situation If one gets same amount of hydrogen and oxygen evolution during the reaction the peak area of oxygen will always be less than the peak area of Hydrogen. Since the thermal conductivity of hydrogen is highest (45.9) the response is higher than oxygen ( Thermal conductivity of oxygen 6.6 which is very close to Nitrogen 6.4). I used both MS-5A and a porapak Q column and was able to detect both Hydrogen and Oxygen with Nitrogen as the carrier gas. Prof Yukun Zhu has also suggested for MS-5A column.

Thank you Prof Yukun Zhu

Thank you Bikash Sharma ..Actually, when I used N2 carrier gas, I also got two peaks (at retention time of 0.4 min and 0.9 min) which I predict that they are the peak of H2 (0.4 min) and O2 (0.9 min). The peak area of O2 is very small compared to H2 peak area.

The retention time is also suitable with the retention time of known O2 and H2 when I did the calibration of O2 and H2 individually using N2 carrier gas. Then, I got the linear equation of two calibration curve.

But, when I converted the peak area of O2 and H2 from water splitting to the concentration of O2 and H2 by using linear equation from calibration curve, I got the concentration of O2 is higher than H2. Is it possible? I think H2 concentration should be higher than O2 concentration. I'am very grateful of opinion and suggestion from you.Thank you very much.

Respected Madam Riza Ariyani Nur Khasanah , Yes it is possible to get more oxygen or more hydrogen or even only one of these gas during the water splitting process. It depends on many factors such as catalyst used, pH of the reaction medium and use of various sacrificial agents. Also we need to purge the reactor with nitrogen or argon gas before the start of the reaction as if oxygen contamination before the start of the reaction will also lead to higher amount of oxygen in the reactor.

Dear Riza,

" The peak area of O2 is very small compared to H2 peak area. " This is the reason why Ar is better.

" I got the concentration of O2 is higher than H2. " This is due to a contamination from air. If you use Ar, you will see the peak of N2 from air contamination and can do appropriate corrections for O2 yield.

Dear Bikash,

" Also we need to purge the reactor with nitrogen or argon gas." If you purge by Ar, you will see a huge peak of Ar on your GC traces.

Ar is definitely the best gas carrier for GC. You also need to purge your system with Ar

Respected Prof Yurii V Geletii , thanks for correcting me.

Dear Bikash Sharma , I used KOH 1 M solution, and before I did water splitting experiment, I filled the electrolyzer with N2 (same gas as carrier gas) and hope all the space in the electrolyzer is filled with only N2 gas. Thank you

Dear Prof Yurii V Geletii .. Thank you very much for your explanation..But, the problem is in the GC 7890B software, there is no Ar gas option in TCD configuration. Is it possible if we separate the experiment of water splitting to two measurement? I mean that (1) measuring H2 concentration by using N2 carrier gas and then (2) measuring O2 by using He carrier gas. But, it seems it is not in the same time, we just can keep the same parameter. In our lab, we also have He gas.

Dear Riza,

I recommend you to contact Agilent (or the vendor of your instrument) for support. Don't forget that all molecular sieves columns require frequent activation

You need to compare the thermal conductivity of your analytes in relation to carrier gas - this is the basic operation of TCD.

Thus, He is not good for H2. The best would be N2.

It is not so important which gas you will implement in your software - the differences in the flowrates are small. Connect the gas line which you need to your GC and perform the analysis.

regards,

GB

Thank you Prof Yurii V Geletii

Thank you Prof @Grzegorz Boczkaj