QuEChERS
Definition
Quick, Easy, Cheap, Effective, Rugged and Safe sample-prep protocol for pesticide residues. Acetonitrile extraction, MgSO4 + NaCl partition, dispersive SPE clean-up with PSA / C18 sorbents. Now standard at most Indian SFSL toxicology divisions.
- Original use
- Pesticide-residue analysis
- Current scope
- Forensic toxicology (poisons, pesticides, drugs)
- Key reagents
- Acetonitrile, MgSO4, NaCl, PSA, C18
Common questions
What does QuEChERS stand for?+
QuEChERS is an acronym for Quick, Easy, Cheap, Effective, Rugged, and Safe. It describes a sample-preparation method that was originally designed for pesticide residues but is now widely used in forensic toxicology to extract and isolate poisons from viscera.
How does the QuEChERS method work?+
The method uses acetonitrile to partition a sample, then adds magnesium sulfate (MgSO4) and sodium chloride (NaCl) to separate the organic layer from water. After that, dispersive solid-phase extraction (SPE) clean-up removes contaminants using PSA and C18 sorbents.
Where is QuEChERS used in forensic work?+
QuEChERS is now standard at most Indian SFSL toxicology divisions for pesticide and toxin analysis. Its simplicity and low cost make it a practical choice for extracting poison residues from viscera.
Related terms
- AChE / BChE
- Acetylcholinesterase (RBC membrane bound, true cholinesterase) and butyrylcholinesterase (plasma, pseudo-cholinesterase). Both depressed in OP and carbamate exposure; plasma BChE falls first and...
- Aluminium Phosphide (AlP)
- Solid grain-fumigant rodenticide sold as Celphos, Quickphos, Sulfas tablets. On contact with moisture or stomach acid, releases phosphine (PH3) gas, which blocks...
- ASE
- Accelerated solvent extraction (Dionex ASE). Pressurised solvent at elevated temperature pushes the analyte off the tissue matrix in minutes, replacing overnight Soxhlet.
- Carbamate
- Carbamic-acid ester insecticides (carbaryl, carbofuran, propoxur, aldicarb). Reversibly inhibit acetylcholinesterase by carbamylating the active-site serine; spontaneous decarbamylation makes oximes unnecessary and sometimes...
- Conway Microdiffusion Cell
- A two-compartment glass or ceramic dish with a central well and an outer ring, sealed at the rim. The poison is released...
- Ellman Method
- Standard spectrophotometric cholinesterase assay. Acetylthiocholine substrate plus 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) yields a yellow 5-thio-2-nitrobenzoate anion read at 412 nm. The rate of...
- Organochlorine (OC)
- Chlorinated hydrocarbon insecticides (DDT, BHC/lindane, endosulfan, dicofol, aldrin, dieldrin). Highly lipophilic, neurotoxic via voltage-gated sodium channel disruption, and persistent in fat and...
- Organophosphate (OP)
- A class of insecticides (monocrotophos, chlorpyrifos, methyl parathion, dichlorvos, phorate) that inhibit acetylcholinesterase, producing the cholinergic toxidrome. The dominant suicidal poison in...
- Pyrethroid
- Synthetic analogues of natural pyrethrins (deltamethrin, cypermethrin, permethrin, fenvalerate). Act on voltage-gated sodium channels like OC but break down quickly in mammals,...
- SLE
- Supported liquid extraction. Diatomaceous earth columns absorb the aqueous sample as a thin film and a single pass of organic solvent elutes...
- SPE
- Solid-phase extraction. Sample is loaded onto a packed sorbent cartridge (C18, mixed-mode MCX/MAX, polymeric Oasis HLB), washed and selectively eluted. The dominant...
- SPME
- Solid-phase microextraction. A polymer-coated fused-silica fibre (typically PDMS or PDMS-DVB) is exposed to vial headspace, then thermally desorbed in the GC injector....
Explained in these topics
- Extraction, Isolation and Clean-up of Poisons from VisceraQuick, Easy, Cheap, Effective, Rugged, Safe. Acetonitrile partitioning with MgSO4 and NaCl, followed by dispersive SPE clean-up using PSA and C18. Originally a...
- Insecticides and Pesticides: Organochlorines, Organophosphates and CarbamatesQuick, Easy, Cheap, Effective, Rugged and Safe sample-prep protocol for pesticide residues. Acetonitrile extraction, MgSO4 + NaCl partition, dispersive SPE cle...