No, you'll have to find an a/c tech. Maybe you know someone who does home a/c repair. They can pressurize with nitrogen and give it a few ounces of R22.

Since you have a sniffer, you might could just put a couple of ounces of R22 in and sniff. If it is a good size leak, there will be enough pressure from just a few ounces that you will probably be able to find the leak. Then it will be verified. If you can't find it that way you won't be able to rule out the leak until you do something further.

But, if it is a profuse leak R22 alone will probably allow you to find it.

Good luck,