INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
1. A simplified approach to the determination of N-Nitroso glyphosate in technical glyphosate using HPLC with post-derivatization and colorimetric detection
MANUELA KIM; JORGE STRIPEIKIS; FERNANDO IÑON; MABEL TUDINO
A simple and sensitive HPLC post-derivatization method with colorimetric detection has been developed for the determination of N-nitroso glyphosate in samples of technical glyphosate. Separation of the analyte was accomplished using an anionic exchange resin (2.50 mm x 4.00 mm i.d., 15 ¥ìm particle size, functional group: quaternary ammonium salt) with Na2SO4 0.0075 M (pH=11.5) (flow rate: 1.0 ml/min.) as mobile phase. After separation, the eluate was derivatized with a colorimetric reagent containing sulfanilamide 0.3 % w/v, [N-(1-naphtil) ethilendiamine)] 0.03 % w/v and HCl 4.5 M in a thermostatized bath at 95 ¨¬C. Detection was performed at 546 nm. All stages of the analytical procedure were optimized taking into account the concept of analytical minimalism: less operation times and costs; lower sample, reagents and energy consumption; minimal waste. The limit of detection (k = 3) calculated for 10 blank replicates was 0.04 mg.L-1 (0.8 mg/kg in the solid sample) which is lower than the maximum tolerable accepted by the Food and Agriculture Organization of the United Nations.