thank you medam,

actually my research area is analysis of pesticides from environmental samples,so which is more sensitive technique or suggest me a good analytical technique..and also give some literature regarding that if possible

In following this thread over the last several days, I have the feeling that Mr. Reddy is unable to describe what he wants to know with enough detail to allow for helpful answers. "analysis of pesticides from environmental samples" is just too broad a definition. Factors that determine what analytical technique to use include the specific compounds to be measured, in what concentration range, in what matrix, and what equipment is available. Analyses are almost always done for a reason.

There is a large literature on environmental analysis and pesticides, including official methods by governmental and intergovernmental agencies. Much of it is online. Unless you can better define your goals, you will be overwhelmed in working your way through the mass of information.

k.thank u sir,

clearly specifying that my research aim is analysis of organo phosporouspesticides from environmental samples afterthat bioremediation of pesticide residues with microorganisms..

so which technique is effective for pesticide analysis from soil samples

I don't specialize in HPLC or organophosphates, but perhaps someone else will suggest good refe3rences on those topics. I mentioned that tyhere are standard methods for such analyses, which have been tested sothat the re3sults will usually be accepted. You can find them at Web sites like one from the U.S. Environmental Protection Agency,

http://www.epa.gov/osa/fem/methcollectns.htm/.

i think , that HPLC is suitable technique for analysis of pesticides in soil . Particular when analyte are polar , termal labile and cannot be determine with GC .

There are multiple methods for organophosphates in soil. All are good methods in the hands of analysts that are competent. None of them are good methods in the hands of people completely lacking the necessary skills. From your posts it is obvious that you do not possess the analytical skills required to use the existing methods. You need to associate with someone who does have those skills; they will almost certainly have a favorite analytical method.

use acetonitrile and water extract ,then concentrate the resisdue, then you injected into hplc

or try quechers methods mgso4 and nacl