How to 301 redirect for this url?

How can I do a redirect on this url?

mydomain.com/product_info.php?products_id=690 to a different domain?

I tried it like this
redirect 301 /product_info.php?products_id=690 http://www.newdomain.com/brand-m-34.html

But it doesn't work. What am I doing wrong?

I want to create individual entries like this for various products to try to carry the SEO weight over to the new domain. After I get this working, the old domain will be shut down.

Thanks for any advice

 

just to make sure, did you type "310" or "301"?

 

Sorry typo. Yes, it was 301

 

that is pretty strange...try a 301 redirect checker, like this one:

http://www.internetofficer.com/seo-tool/redirect-check/

what does it say as a result?