By ves on Thursday, September 11, 2003 - 07:09 am:
I have some waters-oasis hlb spe cartridges and am trying to use these cartridges to extract the atrazine metabolites from soil and water even though waters has the mcx cartridges for this application. The copolymer is the same in both cartridges {poly(divinylbenzene-co-N-vinylpyrrolidone)}, but the mcx material is sulfonated at a few benzene sites (ortho and/or para). I would like suggestions as to how I might adapt the elution on the hlb to accommodate the hydroxylated and non-hydroxylated atrazine metabolites.
mcx method:
sample: pH 1.5 with HCl
SPE condition: MeOH
Rinse: water
load sample
wash 1: 0.1 N HCl
Wash 2L MeOH
Elute: 3 mL MeOH (4% ammonium hydroxide)
The cation-exchange capacity in the mcx cartridge makes me wonder if the sample needs to be acidified to pH 1.5 prior to extraction with the HLB cartridge - or if the hlb cartridge is suitable at all.
By A.Mouse on Thursday, September 11, 2003 - 03:08 pm:
Atrazine is expected to be retained on the Oasis HLB as well, but I prefer to use methods that have been tried by somebody already. I should not take too long to get some Oasis MCX cartridges.
By Michele on Tuesday, September 16, 2003 - 06:43 am:
I have extracted atrazine and several of its metabolites from ground and surface water samples. Atrazine will extract under almost any reversed phase/polymer conditions. Dealkylated hydroxy atrazine metabolites required ion exchange, however, and I have found that the MCX works quite well. Incedentally, is the method posted on their website? I would be interested to see how close it is to mine.
By Anonymous on Wednesday, September 17, 2003 - 01:15 am:
Hi, Ves
in our lab we currently use Oasis HLB cartridges (3 mL 60 mg) for analysis of herbicides residue in water.
Oasis HLB method:
conditioning: MeOH + water milliQ
loading: 200 mL water with no pH correction
washing: water milliQ
elution: MeOH 1 mL
With this method good results are obtained for atrazine, deethylatrazine and deisopropylatrazine.
I have no data for hydroxylated metabolites of atrazine.
By ves on Monday, October 6, 2003 - 12:02 pm:
Thanks, anonymous sep 17. I actually found that the hlb cartridge does ok with a straight methanol elution. The Waters phone-rep said hlb, so I bought, only to find later that the MCX cartridge wa the way to go. A mess, but worked out ok. We worked with hydroxylated atrazines as well and was ok.