Forensic chemistry has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it. | |||||||||||||
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Main Page in the "
Did you know?" column on
November 13, 2015. The text of the entry was: Did you know ... that a
forensic chemist can assist in the identification of unknown materials found at a crime scene? | |||||||||||||
Current status: Good article |
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Well, there is aproximetly zero information about what really are chemical forensics, there are not mentioned fibers, glass, paint, metal, polymer . . . (and so on), FTIR is only one of the methods, and it is used for polymer investigation. I think this article must be expanded The author does not seem to have a good understanding of his tools. Not only does he make generalizations (not all mass specs use EI), but he is flat out wrong about the FTIR: "The molecular bonds of all compounds react differently and create unique patterns upon exposure to a beam of infrared light. The unique pattern created is known as the fingerprint for that drug." there are so many problems with that description, I barely know where to begin. first of all, not all compounds absorb IR, although most compounds of forensic interest will. secondly, "react" is a bad word to use in this description, because anyone who can accurately claim to be a chemist knows that IR light does not have enough energy to essentially any chemistry (there is surely a counter example to this, but they are few). Thirdly, and most importantly, the absorption of IR light by a sample does not "create unique patterns." Basically what I am saying is that FTIR does not work on the principle of emission, it works on the principle of ABSORPTION. the pattern that you look at is the pattern representing the wavelengths of light that have been absorbed, contrasted with those wavelengths that have NOT been absorbed. you are not looking at the pattern of light that was "created" by the compound when it was irradiated with light (emission). In fact, when you are discussing a macroscopic sample (milligrams: you are looking at ensemble properties, not single molecule properties) the EMISSION of IR light is a CONTINUOUS function of wavelength, because the sample, sample holder, hell the entire instrument is a blackbody, and therefore the discrete and highly specific pattern that you are hoping for does not exist for emission, only absorption. also the grammar is kind of poor, not that I claim any better; that is why I did not edit the article. Gordonliu420 ( talk) 06:42, 18 June 2008 (UTC)
Please explain why law enforcement tag has been removed from the article. It is a topic which should be studied by every investigator, police or otherwise. Peterlewis 17:08, 15 May 2007 (UTC)
Hello, I edited the definition of forensic chemistry because it was wrong (in the sense of the English Language). As I pointed out in the article, Forensics is anything of/or pertaining to the courts. This was hammered into me ever since my first day in college as a Criminal Justice major. I cringed when I saw that they had the definition wrong. Don't mean to step on anyone's toes, but I just had to fix it. Sorry and thank you. — Preceding unsigned comment added by 68.201.116.160 ( talk) 20:15, 2 October 2011 (UTC)
GA toolbox |
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Reviewing |
Reviewer: Delldot ( talk · contribs) 16:17, 23 October 2015 (UTC)
I will take this one on. My first question is about how referencing works: many paragraphs have a reference in the middle somewhere, am I to understand it covers the whole thing? What about paragraphs with two references in the middle but none at the end? I prefer each sentence to have its own ref so there's no confusion or problem if the sentences get rearranged.
delldot
∇. 16:17, 23 October 2015 (UTC)
Oh, ok, great. Glad the tags weren't too much of a pain. Yeah, change the table however you think is best, I just saw it in my own browser. I'm about halfway through, and I just have a few little wording comments for the time being. Here's a few things:
Each element has a specific wavelength of light that is used to force the atoms to a higher energy state during the analysis
Forensic chemists can test for each element by using the corresponding wavelength of light that forces that element's atoms to a higher energy state during the analysis?
to confirm the presence of a specific element that might be important in solving the case, after preliminary (or earlier?) tests have suggested it is probably present.Only not that terrible.
AAS should be used as a confirmatory technique after earlier, preliminary, tests have indicated the presence of a specific element in the sample.Preliminary or presumptive, same thing. Since the paragraph then goes right into heavy metal poisoning with a list of elements I decided that saying "elements important/probative to the case" was redundant.
More to follow tomorrow. delldot ∇. 22:01, 23 October 2015 (UTC)
Ok, here's a few more comments mostly around wording. I'm kind of ill-equipped to peer review this I'm finding, but on the other hand I can definitely tell you what doesn't make sense to the uninitiated (I had ochem like 10 years ago). So these are all really minor:
The choice of which detector a lab uses depends on its funding and the precision needed for the type of work it performs.
such as the age of the individual parts of the instrument.
GC-MS is also capable of quantifying the substances in a body, to help forensic chemists determine what effect each substance would have had?
The limit of quantification for GC-MS instruments, unlike detection, is typically in the nanogram (10−9) range.
GC-MS instruments need around 1,000 times more of the substance to quantify the amount than they need simply to detect it; quantification is typically in the nanogram (10−9) range.If this is too overwrought, we can just not worry about "higher limit". Or, what about
The precision of quantification...is lower (worse) than that for detection? delldot ∇. 01:04, 26 October 2015 (UTC)
In general I'm finding as I'm reading that I want to hear more about the specifics of the crime investigation but I'm getting bogged down in the workings of each instrument. e.g. there's one sentence, GC-MS can be used in investigations of arson, poisoning, and explosions in order to determine exactly what was used. I'm like, what sorts of things might it detect? What would they do with that knowledge? I guess I'd like to see more about how a forensic chemist's work fits in with an investigation team's. Does that seem doable to add a few sentences about that? Maybe in the modernization section? delldot ∇. 23:04, 24 October 2015 (UTC)
That's all I got, but I'm eager to see the new info you mentioned above. It occurs to me you might even be able to add an image if you wanted, e.g. of the site of a bombing or fire. delldot ∇. 00:53, 26 October 2015 (UTC)
Sorry it took so long, real life got in the way. Let me know what you think of the new section. I am thinking of what else I can add to it. Any suggestions would be appreciated. -- Stabila711 ( talk) 08:42, 28 October 2015 (UTC)
In cases where an unknown substance is found at the scene, the identification of the substance can tell investigators what to look for during their search
delldot ∇. 16:54, 29 October 2015 (UTC)
A proposal has been made to form a WikiProject for forensic science. Please add your name to the list if you wish to contribute to this endeavour. TimothyPilgrim ( talk) 17:26, 22 September 2020 (UTC)
No concern 2001:FD8:2648:13D8:173E:7A06:1584:C038 ( talk) 01:01, 29 January 2023 (UTC)
Forensic chemistry has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it. | |||||||||||||
| |||||||||||||
A
fact from this article appeared on Wikipedia's
Main Page in the "
Did you know?" column on
November 13, 2015. The text of the entry was: Did you know ... that a
forensic chemist can assist in the identification of unknown materials found at a crime scene? | |||||||||||||
Current status: Good article |
This article is rated GA-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
Well, there is aproximetly zero information about what really are chemical forensics, there are not mentioned fibers, glass, paint, metal, polymer . . . (and so on), FTIR is only one of the methods, and it is used for polymer investigation. I think this article must be expanded The author does not seem to have a good understanding of his tools. Not only does he make generalizations (not all mass specs use EI), but he is flat out wrong about the FTIR: "The molecular bonds of all compounds react differently and create unique patterns upon exposure to a beam of infrared light. The unique pattern created is known as the fingerprint for that drug." there are so many problems with that description, I barely know where to begin. first of all, not all compounds absorb IR, although most compounds of forensic interest will. secondly, "react" is a bad word to use in this description, because anyone who can accurately claim to be a chemist knows that IR light does not have enough energy to essentially any chemistry (there is surely a counter example to this, but they are few). Thirdly, and most importantly, the absorption of IR light by a sample does not "create unique patterns." Basically what I am saying is that FTIR does not work on the principle of emission, it works on the principle of ABSORPTION. the pattern that you look at is the pattern representing the wavelengths of light that have been absorbed, contrasted with those wavelengths that have NOT been absorbed. you are not looking at the pattern of light that was "created" by the compound when it was irradiated with light (emission). In fact, when you are discussing a macroscopic sample (milligrams: you are looking at ensemble properties, not single molecule properties) the EMISSION of IR light is a CONTINUOUS function of wavelength, because the sample, sample holder, hell the entire instrument is a blackbody, and therefore the discrete and highly specific pattern that you are hoping for does not exist for emission, only absorption. also the grammar is kind of poor, not that I claim any better; that is why I did not edit the article. Gordonliu420 ( talk) 06:42, 18 June 2008 (UTC)
Please explain why law enforcement tag has been removed from the article. It is a topic which should be studied by every investigator, police or otherwise. Peterlewis 17:08, 15 May 2007 (UTC)
Hello, I edited the definition of forensic chemistry because it was wrong (in the sense of the English Language). As I pointed out in the article, Forensics is anything of/or pertaining to the courts. This was hammered into me ever since my first day in college as a Criminal Justice major. I cringed when I saw that they had the definition wrong. Don't mean to step on anyone's toes, but I just had to fix it. Sorry and thank you. — Preceding unsigned comment added by 68.201.116.160 ( talk) 20:15, 2 October 2011 (UTC)
GA toolbox |
---|
Reviewing |
Reviewer: Delldot ( talk · contribs) 16:17, 23 October 2015 (UTC)
I will take this one on. My first question is about how referencing works: many paragraphs have a reference in the middle somewhere, am I to understand it covers the whole thing? What about paragraphs with two references in the middle but none at the end? I prefer each sentence to have its own ref so there's no confusion or problem if the sentences get rearranged.
delldot
∇. 16:17, 23 October 2015 (UTC)
Oh, ok, great. Glad the tags weren't too much of a pain. Yeah, change the table however you think is best, I just saw it in my own browser. I'm about halfway through, and I just have a few little wording comments for the time being. Here's a few things:
Each element has a specific wavelength of light that is used to force the atoms to a higher energy state during the analysis
Forensic chemists can test for each element by using the corresponding wavelength of light that forces that element's atoms to a higher energy state during the analysis?
to confirm the presence of a specific element that might be important in solving the case, after preliminary (or earlier?) tests have suggested it is probably present.Only not that terrible.
AAS should be used as a confirmatory technique after earlier, preliminary, tests have indicated the presence of a specific element in the sample.Preliminary or presumptive, same thing. Since the paragraph then goes right into heavy metal poisoning with a list of elements I decided that saying "elements important/probative to the case" was redundant.
More to follow tomorrow. delldot ∇. 22:01, 23 October 2015 (UTC)
Ok, here's a few more comments mostly around wording. I'm kind of ill-equipped to peer review this I'm finding, but on the other hand I can definitely tell you what doesn't make sense to the uninitiated (I had ochem like 10 years ago). So these are all really minor:
The choice of which detector a lab uses depends on its funding and the precision needed for the type of work it performs.
such as the age of the individual parts of the instrument.
GC-MS is also capable of quantifying the substances in a body, to help forensic chemists determine what effect each substance would have had?
The limit of quantification for GC-MS instruments, unlike detection, is typically in the nanogram (10−9) range.
GC-MS instruments need around 1,000 times more of the substance to quantify the amount than they need simply to detect it; quantification is typically in the nanogram (10−9) range.If this is too overwrought, we can just not worry about "higher limit". Or, what about
The precision of quantification...is lower (worse) than that for detection? delldot ∇. 01:04, 26 October 2015 (UTC)
In general I'm finding as I'm reading that I want to hear more about the specifics of the crime investigation but I'm getting bogged down in the workings of each instrument. e.g. there's one sentence, GC-MS can be used in investigations of arson, poisoning, and explosions in order to determine exactly what was used. I'm like, what sorts of things might it detect? What would they do with that knowledge? I guess I'd like to see more about how a forensic chemist's work fits in with an investigation team's. Does that seem doable to add a few sentences about that? Maybe in the modernization section? delldot ∇. 23:04, 24 October 2015 (UTC)
That's all I got, but I'm eager to see the new info you mentioned above. It occurs to me you might even be able to add an image if you wanted, e.g. of the site of a bombing or fire. delldot ∇. 00:53, 26 October 2015 (UTC)
Sorry it took so long, real life got in the way. Let me know what you think of the new section. I am thinking of what else I can add to it. Any suggestions would be appreciated. -- Stabila711 ( talk) 08:42, 28 October 2015 (UTC)
In cases where an unknown substance is found at the scene, the identification of the substance can tell investigators what to look for during their search
delldot ∇. 16:54, 29 October 2015 (UTC)
A proposal has been made to form a WikiProject for forensic science. Please add your name to the list if you wish to contribute to this endeavour. TimothyPilgrim ( talk) 17:26, 22 September 2020 (UTC)
No concern 2001:FD8:2648:13D8:173E:7A06:1584:C038 ( talk) 01:01, 29 January 2023 (UTC)