Off-Line Solid-Phase Microextraction and Capillary Electrophoresis Mass Spectrometry To Determine Acidic Pesticides in Fruits

Abstract

A method based on solid-phase microextraction (SPME) and capillary electrophoresis/mass spectrometry (CE/ MS) is described for determining simultaneously five acidic pesticides (o-phenylphenol, ioxynil, haloxyfop, acifluorfen, picloram) in fruits. The CE device is coupled to an electrospray interface by a commercial sheath-flow adapter. Emphasis is placed on fulfillment of the speed and sensitivity requirements. The best separation is achieved using 32 mM ammonium formate/acid formic buffer at pH 3.1, with a working voltage of 25 kV. The MS detection of the five pesticides was performed in negative ionization mode. Full-scan spectra with base peaks corresponding to [M-H]- were obtained except for acifluorfen, which gives [M-H-CO2]- as most abundant ion. Compared with the conventional EC-UV, the limits of detection were lower for acifluorfen, haloxyfop, ioxynil, and picloram, by a factor of 20, 20, 50, and 2, respectively. Extraction involved fruit sample homogenization with an acetone-water solution (5:1), filtration, and acetone evaporation prior to fiber extraction. SPME conditions such as time, pH, ion strength, stationary phase of the fiber, sample matrix, and desorption solvents were examined. The recovery of the analytes ranged from 7 to 94%, and the relative standard deviation was between 3 and, 13%. The method was found to be linear between 0.02 and 500 mg kg(-1) with correlation coefficients ranging from 0.992 to 0.997. The limits of quantification were from 0.02 to 5 mg kg(-1). The optimized method was successfully applied to the analysis of acid pesticides in fruit samples.

Recent advances in the application of capillary electromigration methods for food analysis

“…Therefore, fast and sensitive analytical procedures are required by the analytical laboratories to face this important demand. In this sense, CE has mostly been applied to detect different type of pesticides in foods [120][121][122][123][124][125][126][127][128][129][130][131], although some other interesting applications as detection of veterinary drugs [132][133][134], toxins [135][136][137] and bacteria [138,139] have also been carried out by CE.…”

Determination of ortho-Phenylphenol Residues in Lemon Rind by High-Performance Liquid Chromatography with Electrochemical Detection Using a Microbore Column

“…The detection limit of each method was expressed as gram per milliliter to be more clear. Compared to other methods, including conventional HPLC-ECD, 7 HPLC-UV, 6 HPLC-FL, 4 LC-MS, 8 CE-MS, 9 and GC-MS, 10 the present µHPLC-ECD was more sensitive. Furthermore, the sample preparation for the present µHPLC-ECD was quite simple, in which twice the hexane extraction was sufficient.…”

“…Those methods include high-performance liquid chromatography with UV detection (HPLC-UV), 6 HPLC with electrochemical detection (HPLC-ECD), 7 HPLC with fluorescence detection (HPLC-FL), 4 liquid chromatography with mass spectrometry detection (LC-MS), 8 capillary electrophoresis with MS detection (CE-MS), 9 and gas chromatography with MS detection (GC-MS). 10 MS detection is a highly sensitive detection method, but usually needs complex and time-consuming sample preparations, including derivatization and solid or liquid extraction, when applied to biological samples, such as agricultural products.…”

QuEChERS: um método moderno de preparo de amostra para determinação multirresíduo de pesticidas em alimentos por métodos cromatográficos acoplados à espectrometria de massas

“…18 Durante os anos 1990, devido às fortes pressões de ambientalistas e também a fatores relacionados à saúde humana, ocorreu um grande desenvolvimento de métodos alternativos de extração baseados na redução do volume de solvente utilizado na etapa de extração. [19][20][21] Entre estes novos métodos podemos citar a extração em fase sólida (Solid Phase Extraction, SPE), 22 a qual também tem sido empregada com frequência na etapa de purificação do extrato para amostras de alimentos. 23,24 Outros métodos que foram desenvolvidos neste período também tinham como objetivo a simplificação de etapas como, por exemplo, dispersão da matriz em fase sólida (Matrix Solid Phase Dispersion, MSPD) e microextração em fase sólida (Solid Phase Micro Extraction, SPME).…”