Tap water or deionised water ?

[Newchromatographer]

Hi there ,

Some people use natuarl water as condition for pesticide to live in it or to mimic the bahaviour of pesticide in natural water and then analyse it using HPLC .I said to them you must use deionised water as you are doing HPLC analysis ? but not sure if they are correct ?

which is correct in term of better mimic study and in term of seperation quality ?

Thanks

[tom jupille]

Water used as part of the HPLC mobile phase should be deionised as a minimum. Ideally, "HPLC grade" water is free of both ionic and organic contaminants.

[DSP007]

Water used as part of the HPLC mobile phase should be deionised as a minimum. Ideally, "HPLC grade" water is free of both ionic and organic contaminants.

Hi
Yes - used "HPLC grade water" - is optimal .
Many years ago ( when reverse osmosis and ozonation have not yet invented) high purity water manufacting whih duble disstilation in quartz glass.From distruction of phenols, pyrogenic bacterial toxin and other organic compound puted one crystal KMnO4 and dripped a drop of H2SO4 per liter.
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Do You have to deal with this sadomasochism now?

PS. Which pesticides are HPLC determined. It seems that I am in Moscow have missed something

[carls]

Hi there ,

Some people use natuarl water as condition for pesticide to live in it or to mimic the bahaviour of pesticide in natural water and then analyse it using HPLC .I said to them you must use deionised water as you are doing HPLC analysis ? but not sure if they are correct ?

which is correct in term of better mimic study and in term of seperation quality ?

Thanks

Tap water is more like natural water than HPLC grade water. If they're trying to mimic the degradation that happens is surface waters tap water is reasonable but MUCH cleaner than surface waters (i.e. lakes, rivers). Tap water also includes chlorinating agents as well as a source of fluoride which are not typically found in surface water sources. These chemicals could skew the degradation profile but I have no data to support this. On the other hand surface waters have MANY components that tap water does not have which very likely affect the degradation profile.

Obviously use HPLC grade water for your mobile phase. Injecting small amounts (10uL?) of tap water (i.e. your samples) will not damage your HPLC column or affect the separation quality.

[DSP007]

Obviously use HPLC grade water for your mobile phase. Injecting small amounts (10uL?) of tap water (i.e. your samples) will not damage your HPLC column or affect the separation quality.

In Moskow tap water is clearing. But use tap water in chromatography phase and sample dilution ... [ дикость и варварство ] savagery and barbarism. Only distillated, or bidistillated.

[Ryklys]

[quote="DSP007/.../ PS. Which pesticides are HPLC determined. It seems that I am in Moscow have missed something [/quote]


I can not answer specifically, but do know that not all pesticides can withstand high temperatures of GC thus are analysed by HPLC. Our lab does pesticides analysis and we had intentions to employ our HPLC system, so did kind of research almost a year ago.