RTX Solution

[lloydthomas]

Re: processing of evidence,

I am interested in hearing from anyone who has used a solution of ruthenium tetroxide (RuO4) called "RTX" developed by Kenzoh Mashiko.

I would like to know how you used the solution and how effective the process was.
I understand that one method of application involves the use of some kind of bubbling device to spread the vapors produced over the item for processing, and so I would like to know exactly what kind of device this is and where I could obtain it.

Thanks

Lloyd Thomas

[Bob/Holly/Barb (DPD)]

We've tried RTX a few times, especially for an alternative to ninhydrin for thermal paper surfaces. It hasn't been all that productive in results though, so admittedly it's not been used very frequently. Although on an experimentation done on nitrated cigarette paper (before processing the evidence cigarette with ninhydrin) it produced the only friction ridge detail results. Iodine, ninhydrin and silver nitrate produced nothing.
We use it with a pressurized air outlet spout in the lab. We've used (what has been described by our chemists as) an "Ehrlenmeyer" flask (with a tapered top opening) that has a "fritted glass fitting" and a commercial glassware "sprayer" (also with a fritted glass fitting to make a seal when the sprayer is inserted into the flask). The liquid RTX is put into the flask to a level above the sprayer interior tube when inserted. A rubber tubing connects the air pressure source to the sprayer nozzle and thumb pressure on the sprayer vent hole controls the fumes that escape through the sprayer tube once the liquid has been pressurized in the flask. It releases a very fine spray directly over the evidence surface. The reaction is very similar to iodine fuming. This sounds more complicated than it is in reality, and probably any lab glassware catalog would have the needed equipment (i.e. Pyrex or Corning).
We've also tried it with a pressurized air aerosol can attached to a plastic sprayer container, but the fumes were too dispursed and it didn't seem to work as well.
Hope this helps.

[NEVILLE MORRIS]

RTX IS JUST A DIFFERANT FORM OF IODINE FUMING, HOWEVER IT WORKS BETTER THAN IODINE FUMING.
WE HAVE USED IT IN AUCKLAND NZ FOR YEARS VERY SUCCESSFULLY ON ANY PRINTS IN GREASE.
WE USE A SMALL BATTERY OPERATED SPRAYER PURCHASED FROM A HOBBIE SHOP, VERY CHEAP AND PORTABLE.
WE FOUND IT LASTED A FEW YEARS BEFORE FALLING APART. DUE TO THE IODINE CONTENT IT WILL RUST ANY METAL PARTS. SO LOOK FOR SOMETHING MADE FROM AS MUCH PLASTIC OR GLASS AS POSSIBLE.

[Scott Verbonus]

Lloyd,
I know Pierce County Sheriff has used this process but it is very expensive. If you call them, I would ask for Steve Wilkins if you want to know more about it and how they use it in their case work.

Good luck,
Scott

[William Pepsis]

Lloyd,
Scott is correct about the high cost. Currently RTX is expensive, I made contact with Mr. Mashiko a while back about the prohibitive cost factor when an agency our size (Dallas, TX. P.D.) orders RTX in large quantities. He replied that he must recover the research expenditure since it took so long for its development and then he can consider a price break.
Is the cost worth it? I would have to say yes. RTX reacts "chemically" with the fats/sebum/lipids found in the sebacious gland secretion portion of the fingerprint matrix. Because it is a chemical reaction versus the "physical attraction" of Iodine the results are permanent instead of transitory like Iodine. As far a application we use the fumer device that is also sold with the product. It only requires an air source. Your questions will be easlily answered by making contact with Mr Mashiko as he will provide a sample bottle of the RTX as well as a fumer device as described free of charge. Our section has been using RTX just over a year know and it is part of our processing chemical processing methodology.

[Mike French]

RTX IS JUST A DIFFERANT FORM OF IODINE FUMING, HOWEVER IT WORKS BETTER THAN IODINE FUMING.

As I understand it, there are two main reasons why most departments have abandoned iodine fuming and rely on other methods to develop latents:

1) It is toxic.

2) It is generally only useful on prints that are fresh, dropping off to ineffectiveness in about one week after deposition on sebaceous prints.

Does RTX solve either of these problems?

Thanks,

Mike French
KCSO Latent Lab
mike.french@metrokc.gov

[William Pepsis]

Mike, I must admit I found your first sentence in your last posting interesting, especially since Daubert and Kumho Tire is supposed to have made us all more responsible and accountable for the sciences used in our varied forensic disciplines, but I also have made a similiar type observation.
In my interaction as a trainer with our own personnel and other outside agencies I have found that the main reason given by these agencies or by particular analysts as to why they have abandoned Iodine is the simple fact the results are transitory. This fact requires that they must be set up to photograph the results if obtained, and they just do not want the hassle of having to do that.
As to your first question about toxicity...There is not much in the way of chemical processing for latent fingerprints that that does not have some type of health warning attached to it. RTX does have the unpleasant side effect of producing ozone during the fuming process. But, since it should be used inside a fuming hood (if using the direct fuming method) this mild deterrent is usually avoided. So RTX I guess I could say wins over Iodine in the danger department.
As to your second question...The reduced effectiveness of Iodine on older sebaceous prints is generally considered to be the result of the combination of moisture loss due to drying and because the fats are being absorbed by the porous substrate, effectively reducing the surface area of the fatty acids present which the Iodine fumes are physically attracted to. Although our section has used the RTX for over a year we have not noticed a definative difference between old and new, but admitedly more often than not most of our evidence items would fall into the fresh catagory.
Bottom line...We utilize RTX as our primary "Fat" chemical technique in our chemical processing methodology, but still have available Iodine (for items we don't want damaged) and PD (for older and/or previously wet items). Of course we continue to follow the methodology and go on to Amino Acids reagent chemicals (DFO, 5-MTN / Ninhydrine,etc.) and so on.

[Mike French]

Mike, I must admit I found your first sentence in your last posting interesting, especially since Daubert and Kumho Tire is supposed to have made us all more responsible and accountable for the sciences used in our varied forensic disciplines.

Believe it or not responsibility and accountability was what I was after with my post.

I work in a lab that discontinued Iodine fuming well before I began my employment as an LPE. The reasoning I got was that it is generally a wasted step since other, more reliable methods can be used. I think our opinions of what works well and what does not should be revisited. To me this is in keeping with the spirit of the court opinion of Daubert and Kumho tire.

The transient nature of the prints is not a huge issue for me. Photography comes rather easy to me. But I know I have read that Iodine fuming is rather ineffective within days after deposition. This is important because most of the evidence in our lab generally is not processed for at least one week after collection. It would be illogical to mandate the handling of toxic chemicals, design engineering controls, and consume time on a procedure that is ineffective or redundant.

Thanks for sharing your observations. I think time studies are in order to actually quantify some of your observations (also in keeping with Daubert and Kumho).

Regards,

Mike
mike.french@metrokc.gov