Studies on the Persistence of Pyraclostrobin 10% CS in Acidic, Neutral and Basic Waters by Validated HPLC-DAD Method

Abstract

This paper presents a method for the determination of pyraclostrobin 10% CS, a fungicide used in agriculture, in water samples with different pH values. The method is based on high-performance liquid chromatography with diode array detection (HPLC-DAD) and uses a reversed-phase column and a gradient elution. The method was validated according to the SANCO guidelines and showed good linearity, accuracy, precision, sensitivity and selectivity. The method was applied to study the persistence of pyraclostrobin 10% CS in acidic, neutral and basic water under laboratory conditions. The results showed that pyraclostrobin 10% CS was degraded rapidly in basic water with a half-life of less than ten days. The degradation products were identified by HPLC. The study involved exposing water samples to direct sunlight until the end of the experiment. The water samples had different pH levels: acidic (4.0), neutral (7.0) and basic (9.0). The water samples also contained Pyraclostrobin, a fungicide. The researchers collected aliquots of the water samples at various time intervals: 0, 1, 5, 10, 15, 20 and 30 days. The analysis continued until the Pyraclostrobin residues were below the detection limit. The DT50 can vary significantly depending on environmental conditions, such as pH levels. At pH 4, pH 7, and pH 9, the reported DT50 ranges between 6 to 8.1 days, indicating a moderate rate of degradation or dissipation in these conditions. These values suggest that the substance is relatively stable across a range of acidic to basic conditions, with only slight variations in the degradation rate.