Forensics C

[pikachu4919]

In rule f.i., it says "Students may be asked questions on the different methods of detecting fingerprints and the chemistry behind each of these methods." Is detecting fingerprints the same thing as fingerprint development techniques like powers, and ninhydrin fuming?

Yes, that is correct. If you wanted to get really technical, you could say that this rule could also include different kinds of lighting or filtering techniques (i.e. using a blacklight, or a filter for a different wavelength of light) that are used to find fingerprints before you develop them, but an explanation for why it's something that's rarely tested is potentially because it could maybe be beyond the current Chemistry Committee's scope of expertise. I wouldn't know for sure, since I'm not on that committee, but ...it's plausible, based on those I know that are on it.

[Panda Weasley]

I have never used conductivity as a way to distinguish powders simply because I previously haven't had access to reliable conductivity testers. Is it worth learning this test now? Do y'all find it helpful?

Also, I'm just curious what y'alls first step for powder ID is? I enjoy seeing how people approach IDing differently.

[scienceisfunalil]

Does chromatography using coffee filters fall under the rules? The rules say paper and TLC.

[pikachu4919]

I have never used conductivity as a way to distinguish powders simply because I previously haven't had access to reliable conductivity testers. Is it worth learning this test now? Do y'all find it helpful?

Also, I'm just curious what y'alls first step for powder ID is? I enjoy seeing how people approach IDing differently.

1. It's mostly helpful for ionic compounds, not necessarily much else. Even so, that's a pretty broad category, so it's not extremely distinguishing. A lot of people tend to get confused by conductivity testers that always light up if they think that stuff that's not super conductive won't light up at all, but in reality, anything will light up since there are always a handful of ions floating around even in DI water, but the key is in the brightness of the light - conductive materials will cause it to shine very brightly and vice versa for not conductive materials.

2. flame test

Does chromatography using coffee filters fall under the rules? The rules say paper and TLC.

I mean, coffee filters are made of paper...

[kitkathw871]

What’s weird tho is that in the next line of rule 2.b. it says “This sheet” instead of something like “these sheets.” I guess if you interpret the rule before as each team member bringing a sheet, then it should still be two sheets, not one.

Disclaimer: this is my own opinion and may not reflect what SO, inc. actually intended with their wording. If this is something you want to clear up with them, submit an FAQ or Rule Clarification on soinc.org.

I assume they worded it that way because the previous sentence only referred to a single participant's sheet, and there could technically be just one team member competing.

They clarified this rule; yes each participant may have one sheet of paper each. Therefore giving the team 2 sheets total

Can someone link where the clarification comes from? Thanks!

[pikachu4919]

I assume they worded it that way because the previous sentence only referred to a single participant's sheet, and there could technically be just one team member competing.

They clarified this rule; yes each participant may have one sheet of paper each. Therefore giving the team 2 sheets total

Can someone link where the clarification comes from? Thanks!

Click here (the URL is absurdly long)

[Qu€€nMon€y]

I need help with reading a mass spec graph. I do not understand how to find the mass of the substance or the identity of the substance. Can someone send me helpful links?

[Calico4243]

Hello! I'm new to the forensics event for scioly. I was wondering if anyone knows where I could find study materials. Particularly for qualitative analysis, polymers, chromatography, mass spectrometry, and DNA.

[pikachu4919]

I need help with reading a mass spec graph. I do not understand how to find the mass of the substance or the identity of the substance. Can someone send me helpful links?

http://ochem.com/tutorials/mass-spectro ... 3-min.html - This is a pretty solid 30-ish-min video tutorial on many things you need to know about mass spec, but in short, the molar mass of the substance is typically the final peak at the very end and will normally be labeled as "M+" and finding the identity of the substance requires much more work, depending on how much additional information is given beyond the mass spec result itself. These could range from knowing the specific peaks that specific potential parts of a molecule (such as a hydroxyl group, a carbonyl group, or a benzyl group) will result in to knowing how fragmentation works - basically molecules get broken up as they travel through the mass spec machine, they break into fragments of all sorts of sizes, think of the possible resulting fragments from that molecule, then figure out where they may show up on the mass spec. These are just simplified explanations of some of the concepts, and I would suggest reading a section on this in an organic chemistry textbook or online resource for more in-depth information.

Hello! I'm new to the forensics event for scioly. I was wondering if anyone knows where I could find study materials. Particularly for qualitative analysis, polymers, chromatography, mass spectrometry, and DNA.

The Forensics Wiki is a good starting point, and the national supervisor has her own personal website with many resources here. Those can at least get you started, but I cannot emphasize enough that your biggest friend in prepping for this event would be actually practicing the lab portion. You can read all about how different tests are supposed to turn out, but observing them yourself will solidify your understanding of them.

[Qu€€nMon€y]

I'm determined to medal in Forensics but I need help in powder and fiber identification. I have a chart on it in my cheat sheet but I want to know the process that makes the identification fast.