- The Concentration Of The Pesticide Metribuzin Should Be Determined In A Sample With Potatoes First 15 00 Grams Of The 1 (110.84 KiB) Viewed 52 times
The concentration of the pesticide Metribuzin should be determined in a sample with potatoes. First, 15.00 grams of the potatoes are homogenized. The homogenized sample is then added with 15 ml of acetonitrile and 150 ul of an internal standard solution containing 20 ng/ul with the isotope-labeled Metribuzin (d3 Metribuzin) After centrifugation, the acetonitrile phase is transferred to a new test tube. The acetonitrile phase then goes through a QUECHERS purification, and finally, some of the acetonitrile extract is analyzed together with 5 calibration solutions using GC-MS. An overview of the composition of the calibration solutions as well as measured peak areas for all the samples is given in Table 1. Calculate the concentration of Metribuzin (ng/g) in the original potato sample. Table 1: The concentrations of Metribuzin and internal standard (d3-Metribuzin) in five calibration solutions (K1-K5) as well as measured peak area for Metribuzin and IS in all solutions. Solutions Concentration of Concentrate lake area, Top area, Metribuzin (ng/ml) of IS Metribuzin IS (ng/ml) K1 50 200 145223 593889 K2 100 200 296711 584045 200 200 605439 594286 K4 300 200 912295 604314 K5 400 200 1234002 594478 Potato sample 774682 569029 K3