A fast and easy method was developed for the determination of glyphosate in maize and rice by using liquid chromatography triple quadrupole mass spectrometry with a Dionex Ion Pack column and phosphate buffer mobile phase. Samples were extracted with an acidified methanol solution. An isotope-labeled internal standard was added to the sample before extraction to ensure accurate tracking and quantification. The method's performance was evaluated through a series of assessments to determine the accuracy, precision, linearity, matrix effect, limit of detection (LOD), and limit of quantification (LOQ). The mean recoveries for both matrices were within 70-105% at three fortification levels, including the LOQ. The precision for replicates was <20% (RSD%) for both matrices. Good linearity (R2=0.9982) was obtained over the concentration range of 0.01-1.5 mg kg-1. The LOD was determined to be 0.002 mg kg-1 for rice and 0.004 mg kg-1 for maize. The LOQ was 0.01 mg kg-1 for both maize and rice. Due to its versatility, the proposed method could be considered useful for the determination of glyphosate in cereals in routine analysis.
Keywords: Glyphosate; LC/MS/MS; cereals; herbicide; maize; pesticide residue; rice.