Study On Application And Residue Analysis Of Plant Growth Regulator In Common Fruits And Vegetables In Si Chuan

Si Chuan is the important origins of multiple fruits and vegetables, to study the usage of plant growth regulator and its residue level in fruits and vegetables in Si Chuan, a survey of plant growth regulator usage on the main fruits and vegetables was made and determined residues of plant growth regulator on fruits and vegetables, and optimized the HPLC method of forchlorfenuron. Results were as follows:(1) The usage of 25 plant regulators on 8 kinds of common fruits and vegetables in 23 areas of Si Chuan were surveyed by questionnaire method. The investigation results showed forchlorfenuron was used on loquat, grape, kiwi, cucumber and watermelon, and 98% of the farmers used it on kiwi fruit; Above 23% of the farmers used gibberellic acid in grape, watermelon, tomato and citrus; 2,4-D was the leading plant regulators on tomato, and 69% of the farmers used it on tomato; Individual farmers used brassinolide. Farmers used plant regulator mostly depends on experiences or dealer’s recommendation, basically didn’t observe the instructions in strict.(2) A HPLC rapid detection method for the residue determination of 2.4-D in fruits and vegetables was established.2.4-D residues in 28 samples of fruits and vegetables, including loquat, tomato, grape, etc have been detected. The results showed that 2,4-D was accurately extracted and separated from the samples by C18 solid phase extraction. The linear ranges of 2,4-D was 0.5 μg/ml-5 μg/ml, and the correiation coefficients were 0.998. The average recoveries of 2,4-D in spiked sample ranged from 82% to 116%, the reiative standard deviations were between 1.8% and 5.7%. and the detection limit is 0.001 mg/kg. Residues of 2,4-D were lower than the maximum residue limits standard in China:A GC-MS method for the determination of ethephon in 14 fruit and vegetable samples of, including tomato, cucumber, grape, etc were established. The results showed that the linear range, accuracy and precisionand of method can meet the requirements of residue analysis. Residues of ethephon were lower than the national standard.Forchlorfenuron residues in 22 fruit and vegetable samples, including grape, loquat, kiwi, etc were detected, and by solid phase extraction-high performance liquid chromatography, and detected microscale forchlorfenuron respectively in kiwi, loquat and grapes. The method was verified with loquat as matrix to validate the method. The results showed the recovery rate of forchlorfenuron wasn’t steady-going, leading to the low accuracy and precision. The pretreatment method of forchlorfenuron must be further studyed.(3) A QuEChERS-HPLC method for the determination of forchlorfenuron in loquat was developed. The influences of matrix dispersive solid-phase extraction and QuEChERS on forchlorfenuron analysis in loquat by HPLC were studied from the aspects of impurity interference degree, forchlorfenuron recovery rate, stability. The results showed that the average recovery rate, accuracy and precision of matrix dispersive solid phase extraction was significantly lower than QuEChERS.The conditions of QuEChERS such as different extraction agent and dosage, extraction time, salting out, and dehydrating agent proportion and dosage, purifying agent and purification time to the effect of forchlorfenuron extraction and purification in loquat were further studied. The optimized the conditions of QuEChERS were 8 g loquat,16 ml acetonitrile, extract 20 min, magnesium sulfate anhydrous:sodium chloride=3:2(mass ratio), PSA:C18=1:1(mass ratio), Purify 3 min. By HPLC detection, forchlorfenuron peak was separated from impurity peak obviously, a stable recovery ratio between 80%-100%. RSD were between 3. 1%-4.8%.