TECHNICAL NOTE CRIMINALISTICS/TOXICOLOGY Rafael Lanaro, 1 M.Sc.; Jos e L. Costa, 1,2 Ph.D.; Silvia O. S. Cazenave, 2 Ph.D.; Luiz A. Zanolli-Filho, 3 M.Sc.; Marina F. M. Tavares, 3 Ph.D.; and Alice A. M. Chasin, 4,5 Ph.D. Determination of Herbicides Paraquat, Glyphosate, and Aminomethylphosphonic Acid in Marijuana Samples by Capillary Electrophoresis ABSTRACT: In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15–0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user. KEYWORDS: forensic science, paraquat, glyphosate, AMPA, marijuana, capillary electrophoresis, Cannabis, forensic toxicology According to the World Drug Report 2010 issued by the Uni- ted Nations Office on Drugs and Crime (1), marijuana remains as one of the most consumed drug worldwide, with almost 165.6 million users. A significant increase has been noticed in Brazil from 2006 to 2007, probably due to the greater availabil- ity of Cannabis products coming from neighbor countries (1,2). Some authors showed marijuana contamination by cosmopoli- tan microorganisms (fungi, for example Aspergillus) most of them as mycotoxin producers, which present great toxicological significance (3,19,20). They can lead to occupational allergy in police officers, hypersensitive toxicologists and also in users as they have direct contact through dispersion, inhalation and/or ingestion of spores or hyphae when handling or using the drug. So far, one case of death has been reported as a consequence of chronic use of marijuana contaminated by Aspergillus, due to lung aspergillosis (3). Paraquat is a quaternary ammonium compound used as nonse- lective contact herbicide, used as desiccant and defoliant for the control of weeds and grasses growing in fruit orchards. This substance has a good occupational safety record (occupational injuries are associated with dermal and eyes irritation), but pres- ent a high mortality index after intentional exposure (4,5). Herbicides have been extensive used to control drug produc- tion in last three decades. At the end of 70’s, substances such as 2,4-D and paraquat were used to eradicate marijuana crops in Mexico. Such action was quite controversial due to the paraquat toxicity levels for marijuana users as well as for inhabitants near to the cultivation and herbicide application sites (6, 18). In the last decade, glyphosate [N-(phosphonomethyl)glycine] was used in coca plants eradication program in Colombia (7). This work describes the development of an analytical proce- dure for determination paraquat, glyphosate and its main break- down product—the aminomethylphosphonic acid (AMPA), in marijuana samples by capillary electrophoresis with direct and indirect detection. The proposed procedure is useful to appraisals and assessments on the possible risks that marijuana users can be exposed. Materials and Methods Reagents and Chemicals Paraquat dichloride (1,1 0 -dimethyl-4,4 0 -bipyridinium dichloride hydrate), diquat dibromide monohydrate (1,1 0 -ethylene-2,2 0 bipy- ridylium dibromide monohydrate), glyphosate (N-phosphonom- ethyl-glycine), aminomethyl-phosphonic acid (AMPA) were purchased from Aldrich Chem. Co. (Milwaukee, WI). Ethyl paraquat dibromide (1,1 0 -diethyl-4.4 0 -bipyridinium dibromide) (used as internal standard for paraquat analyses) and glutamic 1 Poison Control Center, State University of Campinas, Campinas, SP, 13083-887, Brazil. 2 Forensic Toxicology and Chemistry Laboratory, Criminalistic Institute of Sao Paulo, SP, 05507-060, Brazil. 3 Institute of Chemistry, University of S~ ao Paulo, SP, 05508-000, Brazil. 4 College Oswaldo Cruz, S~ ao Paulo, SP, 01151-000, Brazil. 5 College of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP, 05508-000, Brazil. Received 19 April 2013; and in revised form 12 Jan. 2014; accepted 6 Feb. 2014. S241 © 2014 American Academy of Forensic Sciences J Forensic Sci, January 2015, Vol. 60, No. S1 doi: 10.1111/1556-4029.12628 Available online at: onlinelibrary.wiley.com