Chlorpyrifos Lab Report

From the experiment, the amounts of chlorpyrifos for three samples were identified. Based on the peaks, the retention times of the samples were between 6.711 until 6.714 minutes. The sample amount of standard was 30ppm. The response factor of the standard sample amount calculated for the standard sample was 11202 Hz s-1/s. Then, from the response factor, the amount of chlorpyrifos could calculate by dividing peak area with response factor. The average amount of chlorpyrifos in sample 1, sample 2 and sample 3 were 8.825 ppm, 23.91 ppm and 18.43 ppm respectively. For the calculation of the average of chlorpyrifos in samples, only sample 2 and sample 3 only were used. Amount of chlorpyrifos in sample 1 was not used and rejected because some error

ECD was selective to organic molecules or analytes that contain electronegative functional groups that can capture electrons. ECD also was widely used for detecting environmental samples. For example, in this experiment, the chlorpyrifos in waste water can be detected by using GC-ECD. Waste water was an environmental sample. Higher sensitivity of the detector caused the larger peak to be produced. The flow of the detection of chlorpyrifos in GC-ECD was firstly the chlorpyrifos that eluted from the column was passed over a radioactive β-emitter. An electron from the emitter causes the ionization of the carrier gas, nitrogen and the production of a burst of electrons. In the absence of organic species, a background current between a pair of electrodes results from this ionization process. When analyte that can capture electrons entered the detector, electrons from the background current are captured hence the current was decreased. The disadvantage of the GC-ECD was it involve radioactive component. Therefore, the analysis of chlorpyrifos can only be analyzed by the authorized person