MQ137 Sensor for low level ammonia detection

Hi There,
I want to use MQ137 sensor for ammonia detection. The process is I heat the water containing NH3 and then direct the vapour through a vent towards the MQ137 sensor. The range I want to measure is from 0ppm to 5ppm, if possible with the lowest possible resolution. Do any one have suggestions?
Thanks in advance

Using words such as "mq137 spec sheet".

I selected this link, which, when looked at and read gives the deets on the thing.

Yes, I have also gone through various datasheet. Most datasheet mention the range of 5 - 200 ppm and the graph is from 5ppm or 10ppm start. But is it possible to use the sensor at a lower ppm value and get the correct results?


Do you any alternate sensor that i would be able to use for ammonia gas detection in range of 0 - 3 (or 5) ppm?
Thanks in advance

Did you use words "ammonia gas detection in range of 0 - 3 ppm" in an internet search? I could do the research for you for a fee.

Why did you choose the MQ137, which responds to lots of different gases and smoke, is not very sensitive to ammonia, and is almost impossible to calibrate?

I did search online for various sensors and MQ137 was the most I found in search results, hence tried to make the circuit with it.

That is not a good reason to choose a sensor.

The entire MQ series is best for one thing: to inform you that something in the air has changed. Because they are cheap, they are also not very reliable.

Yes I did and I found that the sensor start from 0 - 200 or 1 - 200 ppm. But there datasheet show there circuit as the same as MQ137 datasheet. So I am not sure if I can use them.

For example
TGS2602 - 1 - 30 ppm

I do not have an answer for you. I am not going to do your research, prototyping, and development for you.

Sure. Thanks for your valuable advice though

Not possible with those cheap sensors. You need an industrial sensor, and it will be expensive. Here is one example:

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