Dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet for simultaneous analysis of diethofencarb and pyrimethanil in apple pulp and peel

• Published in: Analytical and bioanalytical chemistry Vol. 399; no. 5; pp. 1901 - 1906
• Main Authors: Zhou, YiWen, Han, LinTao, Cheng, Jing, Guo, Feng, Zhi, XiaoRan, Hu, HaiLi, Chen, Gang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2011; Springer
• Subjects: Acetonitrile; Analytical Chemistry; Apples; Biochemistry; Characterization and Evaluation of Materials; Chemical Fractionation - methods; Chemistry; Chemistry and Materials Science; Chromatographic methods and physical methods associated with chromatography; Density; Droplets; Exact sciences and technology; Extraction; Food Science; Fruit - chemistry; Fungicides; High performance liquid chromatography; Laboratory Medicine; Malus - chemistry; Monitoring/Environmental Analysis; Original Paper; Other chromatographic methods; Phenylcarbamates - analysis; Pyrimidines - analysis; Solidification; Solvents; Floating organic droplet; Apple analysis; Pyrimethanil; Diethofencarb; Water; Microanalysis; HPLC chromatography; Solvent extraction; Density; Chemical enrichment; Target; Sample preparation; Detection limit; Microwave irradiation; Diode array; Standard deviation; Low temperature; Speed; Extraction process; Sample; Use; Pesticides; Concentration; Droplet; Fungicide; Organic analysis; Repeatability; Organic solvent; Apple; Analysis method; Acetonitrile; Simultaneous measurement; Microextraction; Detection
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-010-4567-x

A method for analysis of diethofencarb and pyrimethanil in apple pulp and peel was developed by using dispersive liquid–liquid microextraction based on solidification of a floating organic droplet (DLLME-SFO) and high-performance liquid chromatography with diode-array detection (HPLC–DAD). Acetonitrile was used as the solvent to extract the two fungicides from apple pulp and peel, assisted by microwave irradiation. When the extraction process was finished, the target analytes in the extraction solvent were rapidly transferred from the acetonitrile extract to another extraction solvent (1-undecanol) by using DLLME-SFO. Because of the lower density of 1-undecanol than that of water, the finely dispersed droplets of 1-undecanol collected on the top of aqueous sample and solidified at low temperature. Meanwhile, the tiny particles of apple cooled and precipitated. Recovery was tested for a concentration of 8 μg kg −1 . Recovery of diethofencarb and pyrimethanil from apple pulp and peel was in the range 83.5–101.3%. The repeatability of the method, expressed as relative standard deviation, varied between 4.8 and 8.3% ( n  = 6). Detection limits of the method for apple pulp and peel varied from 1.2–1.6 μg kg −1 for the two fungicides. Compared with conventional sample preparation, the method has the advantage of rapid speed and simple operation, and has high enrichment factors and low consumption of organic solvent. Figure Chromatogram of apple pulp (a) and spiked apple pulp (b) at the concentration level of 0.4 μg g −1 for two fungicides obtained by using DLLME-SFO combined with HPLC-DAD. Peak identification: 1-Diethofencarb, 2- Pyrimethanil