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Topic: {Analytical grade reagents}  (Read 3954 times)

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Offline dan2000

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{Analytical grade reagents}
« on: March 03, 2015, 04:16:31 AM »
I've been purchasing stuff from sigma aldrich etc. for my experiments.

I've always noticed the price difference and just went for the cheap/pure ones and worked fine. My question is:

1. Why is stuff in analytical standard category so gxxxxmn expensive?? what sort of experiments uses them? I've performed some titrations/standardization(?) stuff and still got pretty accurate results.

2. Even between same chemical (which isn't standard), no matter how much I compare them I cannot find the slightest difference yet their prices differ so much. I'm guessing this depends what companies produces them, but why such gap? Is the purity not enough to determine the actual quality of the chemical?
« Last Edit: March 03, 2015, 10:13:30 PM by Arkcon »

Offline curiouscat

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Re: This question might not really belong but...
« Reply #1 on: March 03, 2015, 07:40:06 AM »
Sometimes trace impurities. It can cost as much to go from 99% pure to 99.99% pure as it does to make the 99% pure in the first place.

Some of it is also the cost of the requirement to test in house for lots of tiny impurities that are very finicky to quantitate. You might get a certificate. Or provenance, batch nos. etc.

There's also price discrimination. 

Finally, they charge you coz' they can? There's not that much competition. Sigma's brandname matters a lot. Profit margins must be decently good. Besides, to be fair they do have to hold a lot of inventory of esoteric stuff that might get ordered so rarely. But that applies to both grades.

Offline Arkcon

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Re: This question might not really belong but...
« Reply #2 on: March 03, 2015, 09:18:13 AM »
Furthermore, its not just that analytical grade reagents are 99.9% pure, and other reagents are (possibly) 99% pure.  Its that vendors of analytical grade reagents certify that they are at the purity level they report.  They have checked the reagent, against an aliquot of federally recognized standard, generally a USP standard, by a certified technician, performing an analytical method that the certifying body will accept.  And they do check that the technicians at the company is performing to the correct standard.  Such certification is provided to you when you purchase the analytical grade reagent, and you're required to reference the document in your own work, and produce the referenced on demand by a regulatory body.

Query:  You've "performed some titrations/standardization(?) stuff and still got pretty accurate results."  What does that mean?  Are you testing foods for human or cattle consumption?  Or are you testing raw materials, excipients or finished pharmaceuticals?  Do you test fine chemicals, and guarantee your results to a certain standard -- example, you'd never report your results to greater significant figures than your starting material.  You wouldn't report the result of your assay as 99.45%, if your reagent was only known to be 99.9%, correct? 

If you have violated these rules, an independent auditor will want you to correct these shortcomings, before a federal auditor shuts down your company.  And if you try to deceive people about your shortcomings, it isn't impossible for you to land in federal prison.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline curiouscat

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Re: This question might not really belong but...
« Reply #3 on: March 03, 2015, 10:45:44 AM »

And if you try to deceive people about your shortcomings, it isn't impossible for you to land in federal prison.


Just my overactive curiosity but have you known / heard of any analytical / lab chemists ending up in prison coz' they fudged some results?

Might make an interesting case study.

Offline Arkcon

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Re: This question might not really belong but...
« Reply #4 on: March 03, 2015, 10:59:49 AM »
I used to think that never happened, that you could always plead it down to a serious fine or other lesser punishment.  But I did hear about a lab manager who did some analytical work on her own in the lab.  And it did blow up in her face.  My group leader gave me the name of the company she worked for, but I've forgotten it.  I really did want to read the circumstances myself as well.  But she went for a short time, 4 years maybe, to women's Federal prison.  She went in a typical scientist, shy, sweet, intellectual, kinda cute for almost middle age, and she came out, as he put it, "pretty hard" after the prison system was through with her.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline curiouscat

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Re: This question might not really belong but...
« Reply #5 on: March 03, 2015, 11:07:30 AM »
I used to think that never happened, that you could always plead it down to a serious fine or other lesser punishment.  But I did hear about a lab manager who did some analytical work on her own in the lab.  And it did blow up in her face.  My group leader gave me the name of the company she worked for, but I've forgotten it.  I really did want to read the circumstances myself as well.  But she went for a short time, 4 years maybe, to women's Federal prison.  She went in a typical scientist, shy, sweet, intellectual, kinda cute for almost middle age, and she came out, as he put it, "pretty hard" after the prison system was through with her.

Sad.

Sorry, did you mean it like literally blew up in her face? Or you mean she lied on some test? 4 years in federal prison sounds pretty long to me. Funny that you'd call it "short".

In hindsight, I've known some Chemists get jail time too but they all got caught while trying to dabble in  illegal drug making. Some were actually grad students.

Offline Darryl1

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Re: This question might not really belong but...
« Reply #6 on: March 03, 2015, 01:41:56 PM »
This goes without saying, but don't ever fudge your results.  If they don't make sense, redo the test.  If they still don't make sense, something may be wrong with either what you are testing or what you are doing.
Where I work (and I hope every other place), anyone caught fudging results immediately gets fired.  Anything less is irresponsible.

-d

Offline dan2000

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Re: This question might not really belong but...
« Reply #7 on: March 03, 2015, 09:22:08 PM »
If you have violated these rules, an independent auditor will want you to correct these shortcomings, before a federal auditor shuts down your company.  And if you try to deceive people about your shortcomings, it isn't impossible for you to land in federal prison.

lol sry i wasnt being so clear. No, i'm not fudgin up my results, and im just a simple grad student. By standard etc stuff I meant that my test results for toxicity(not exactly, but for the simplicity) were the same with the results from 'certified' gov. department (needed this to ship out my material to some company). Obviously the official tests were waaay more expensive than when I did it, but I guess for companies to test products themselves they need that extra certificate that comes with analytical standard thing.

Anyways, that was bothering me for long time, thanks for the replies.

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