By ves on Thursday, January 15, 2004 - 02:13 pm:
We have a graduate student who has taken water samples from a well about 60 feet deep in Lenior County, North Carolina in a cultivated crop zone. The soil is sandy loam. The well is used for irrigation of corn, soy, and cotton. He had a list of known, suspected herbicides and pesticides. Few of these were found (Simazine and Atrazine in low concentrations - October sampling time). There were other peaks that had PDA spectra suspicously like herbicides. Is there a public domain repository of PDA spectra of herbicides and pesticides somewhere - a book? There is one compound that had a spectrum of three peaks.
Pk 1: 202nm: abs - 0.017
Pk 2: 225nm : abs - 0.0025
Pk 3: 275 nm: abs - 0.005
Anyone fathom an educated guess?
An interesting but difficult thesis and quite necessary.
By Anonymous on Friday, January 16, 2004 - 11:02 am:
Hi.
does your university have a Mass Spec lab? Ours has a few LC-MS machines and people who could help grad students to use them. That way you could search ready-made databases that might be more complete.
Of course there's also LC fraction collecting / NMR or mass spec for identification.
best of luck!
By ves on Wednesday, January 21, 2004 - 01:31 pm:
mass spec is broken, and it is gc/ms. have a fraction collector, but there's too little in the sample to get enough material for nmr identificaion. he had tearget analytes but few hits (some simazine, atrazine). the notable peaks look like crop applicants - pda. just thought his might ring a bell or someone might know of a collection of pda spectra of herbies and pesties.