CLPEX Chat Board

For those of you who use this CA stain, do you but it pre-mixed or mix your own. If you mix your own, where in the world do you buy the MBD?

Thanks in advance.

Andrew,

Our last purchase of MBD (April 2005) came from the following company:

Sigma Aldrich Inc.
3050 Spruce Street
St. Louis, MO 63103

314-771-5765

John

John,

Looking up Sigma's MBD I have a question. The chemical name that Sigma lists is: 4-(4-Methoxybenzylamino)-7-nitro-2,1,3-benzoxadiazole

According to the FBI Processing Guide for Developing Latent Fingerprints the chemical name is: 7-P-methoxybenzylamino-4-nitrobenz-2-oxa-1-3-diazole

Do you, or anyone else for that matter, know the difference? The chemical names appear pretty similar, but I am not a chemist. I want to make sure that I am looking at the right stuff.

Thanks for the information.

Andrew

Andrew,

I recall having the same question myself prior to ordering, and I am a chemist. Sometimes the IUPAC names for chemicals are rather confusing. In fact, our bottle of MBD is listed as 4-(4-Methoxybenzylamino)-7-nitrobenzofurazan, which is different from the two you listed. The key is to always check the CAS number - in this case, 33984-50-8. If you research this, you'll find all the names we've mentioned, including the acronym MBD.

I hope this helps.

John

John,

Thank you for the information. I looked up the CAS Numbers and found the name that the FBI guide lists as well as a couple others (yours and sigmas).

Thanks for helping me striaghten this out.

Andrew

John, Andrew,

Just a side note about using RAM. I have had problems with the rhodamine precipitating out of the working solution when using petroleum ether as the carrier. The cause eluded me for some time then I checked the petroleum ether bottle. Apparently a low-grade anhydrous ether was purchased to save a few bucks by our admin. I found that a higher grade needs to be used with at least a low-end BP range starting at 40C or higher. The 30C did not work. Have you experienced this same problem?

Tomelo suave

DJ

I have experienced this same type of precipitation with RAM. It very well may be the grade of pet. ether. I haven't tried that approach. Instead of changing the pet. ether type, I have had success with giving the glassware a good acid rinse, followed by a distilled water rinse. New glassware has also solved the problem. This approach allows for the continued use of a cheaper grade of Pet. ether. I would like to hear from other agencies on this issue of RAM precipitation as I am sure there are chemists out there that can provide additional insight.

I was ordering the MBD from Sigma and noticed it should be stored is at -20 C. Is this required? What about the stock solution (1g MBD/1L Acetone), does it need to be stored in the fridge?

The FBI Processing guide doesn't note anything about temp. in the storage part, neither does the Chesapeake Division IAI's reagent guide.

Concerning the shelf life of the working solution........the FBI processing guide states that "The RAM solution is stable for approximately 30 days. After 30 days, it should be checked for separation. If the solution has separated, shake the container vigorously, and the solution will usually return to suspension. If this does not occur, discard the solution." Then it goes on to say "All the ingredients for the RAM working solution, with the exception of the petroleum ether, may be mixed and stored. When it is time to mix the RAM working solution, the appropriate amount of petroleum ether can then be added. Once the petroleum ether has been combined with the other ingredients, the 30 day shelf life begins."

I am wondering then, what is the shelf life of this particular chemical?? If you can shake it after 30 days, when does it truly expire? The Chesapeake Bay Division's website states it is only good for one month. For anyone that uses this formula, what do you follow for an expiration? Thanks!

Michelle L. Snyder

We ordered our MBD through a company called Spectrum and it was shipped to us on a gel type refrigerant ice pack. The instructions on the bottle advise to store at 0 degrees C. If interested, the order information is as follows:

Spectrum Chemical
14422 S. San Pedro Street
Gardena, CA 90248
1-800-772-8786
www.spectrumchemical.com

Catalog No. M3009-1GM
Lot No. VX0568

Usually I toss it out if its more than a month old. But I only make very small quantities at a time, so I usually never have that problem.

I mix everything up but the Pet E as a stock solution, and then use the Pet E to make a small amount of stock solution. Usually just make enough to process a couple cases.

In my past experience, we have always made RAM up in large batches (couple of liters). Sometimes this is used up in a couple weeks, sometimes it takes two or three months -- all depends on the caseload at the time. I've never had it go bad on me, and I QC it every time I use it to make certain that is true.