Determination of organochlorine pesticides in organic quinoa grains (Chenopodium quinoa Willd.) by GC-mu ECD, using the QuEChERS method

There is currently great interest in environmental pollutants in relation to food security; previous studies show that persistent organic pollutants (POPs) could be found in small amounts, even in organic food; therefore, in this research, 12 organochlorine pesticides residues (p, p'-DDD; p, p'-DDE, o,p'-DDD, o,p'DDE, Dicofol, alpha-endosulfan, beta-endosulfan, endosulfan sulfate, alpha-BHC, beta-BCH, heptachlor and mirex) were monitored in quinoa grains from organic production systems, sampled in the region of Puno-Peru; the QuEChERS method was used for pesticides extraction and gas chromatography coupled to an electron capture detector (GC-mu ECD) for the detection and quantification of the pesticides. The method was validated using a quinoa sample without pesticide residues used as a blank and spiked to 0.01 and 0.10 mg kg-1; means recoveries for pesticides ranged from 73.66 to 128.09% with RSD <= 16%; the method showed linearity of r2 >= 0.99 and the Limits of Quantification (LOQ) ranged from 0.001 to 0.010 mg kg-1. The results indicate that there is no matrix effect and reveal the presence of three organochlorine pesticides (p, p'-DDD, p, p'-DDE and mirex) in five different samples; two of them showed concentrations of p, p'-DDE above 0.01 mg kg-1. The results demonstrate the susceptibility of quinoa grain to the accumulation of toxic substances and show the need to establish new criteria for organic certification.