what is lc mainly used for

[chemist]

I now what lc is but I don't now enough about it. Can anyone give more info?? It would be greatly appreciated

[tom jupille]

In order to analyze anything, you have to separate it into its components. Imagine someone handed you a mixture of sand and sugar and asked you to find out how much (what percentage) sand it contined.

How would you do it? (think about it, then scroll down to see the answer below):
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Answer: by weighing out some of the mixture, then separating the sand and sugar into separate piles and weighing the sand.

Hopefully, you have found out from your reading that chromatography is a technique for separating different chemical compounds (most things are a lot harder to separate than sand and sugar!). It's used to analyze almost everything:

• - how much aspirin is in a tablet
  - how much MTBE (formerly used as a gasoline additive) is in your well water,
  - how much sulfate is in acid rain,
  - how much iso-octane is in your gasoline,
  - what flame-retardant is on your pajamas,
  - what poison was used to kill your murder victim (and how much was used),
  - and on and on and on.

You can scan through the titles of the posts on the GC and LC boards to get a list of specific compounds; if you read the posts, you'll find that they come from people working with pharmaceuticals, petrochemicals, foods, forensic chemistry, environmental analysis, . . . you name it.

The choice of LC or GC depends on whether the compound to be analyzed is more conveniently handled as a liquid or a gas. Many labs use both technques, depending on the sample.