Determinazione di pesticidi in matrice cheratinica

The aim of the present work is to investigate the suitability of an unconventional biological matrix such as hair for the determination of pesticides. Focus has been put on the major classes of pesticides: organochlorines, organophosphates, carbamates, triazines, pyrethroids and neonicotinoids. These analytes are toxic when they enter the human body, being possibly carcinogenic and detrimental to the nervous system. 311 hair samples from pregnant French women and 142 hair samples from French children were analyzed following the same procedure: decontamination of hair by washing it with SDS, drying, pulverization, extraction, purification with SPE cartridges and analyses via GC-MS/MS. Blanks were run to confirm the absence of cross-contamination, since it is frequent in a complex matrix such as hair, which contains a remarkable percentage of proteins and lipids. Approximately 20 pesticides were detected in 90% of women and 9 in 95% of children, including organochlorines found in both populations: lindane, hexachlorobenzene, pentachlorophenol. Such organochlorines have been banned in Europe for at least a decade and their detection is hence worrying. On the other hand, 101 hair samples from either agricultural workers or non-occupationally exposed people living in Burkina Faso were analyzed using a modified QuEChERS method: hair was decontaminated washing it with SDS, then it was cut into very fine fragments and dried; extraction followed and a Z-SEP+ dSPE cleanup sorbent led to clean chromatograms obtained via GC-MS/MS and UPLC-MS/MS runs. Neonicotinoids acetamiprid and imidacloprid were the most frequently detected pesticides in this population, with an average of 4 pesticides per person, among with a consistent DDT contamination due to the malaria prevention. Different analytical methods are examined, discussing the necessity for a purification step prior to chromatographic runs. A more extensive use of LC instead of GC has been made in the most recent methods, because higher sensitivity has been reached in analyses via LC-MS/MS due to the mass spectrometry coupling. Successful detection of 300 pesticide residues has been achieved. Hair demonstrated to be a suitable matrix for the detection of all classes of pesticides except for atrazines and their metabolites. It also provided a non-invasive sampling procedure and a larger detection time frame, if compared to biological fluids such as blood, urine and saliva. No standard procedure has been validated up to date, though, and evaluation of specificity, precision and accuracy is expected to be therefore difficult.