Pesticides In Olive Oil Research Articles

A comprehensive HRMS methodology using LC-(ESI)-/GC-(APCI)-QTOF MS complementary platforms for wide-scope target screening of >750 pesticides in olive oil.

This study presents the development and validation of a comprehensive high-resolution mass spectrometry (HRMS) methodology for the detection of 771 pesticides in olive oil, using liquid chromatography with electrospray ionization, operating in positive and negative mode, and gas chromatography with atmospheric-pressure chemical ionization in positive mode, both coupled to quadrupole-time-of-flight mass spectrometry (LC-(ESI)-/GC-(APCI)-QTOF MS). Special reference is made to the post-acquisition evaluation step, in which all LC/GC-HRMS analytical evidence (i.e. mass accuracy, retention time, isotopic pattern, MS/MS fragmentation) is taken into account in order to successfully identify the compounds. The sample preparation of the method involves a QuEChERS-based protocol, common for both techniques, differentiated only on the reconstitution step, making the method highly applicable in routine analysis. A smart evaluation of method's performance was carried out, with 65 representative analytes comprising the validation set. The method was validated in terms of linearity, accuracy, matrix effect and precision, while the limits of detection and quantification of the method were estimated. Finally, twenty Greek olive oil samples were analysed in both analytical platforms and the findings included the pesticides lambda-cyhalothrin, chlorpyrifos, phosphamidon, pirimiphos-methyl and esprocarb at low ng g-1 level.

Risk assessment of polycyclic aromatic hydrocarbons and organochlorine pesticides in olive oil in Jordan

Many organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) pose risks to human health; so, their levels in foods should be constantly monitored. In the present work, the potential health risks of 21 OCPs residues and 16 carcinogenic PAHs in Jordanian olive oil were evaluated. A total of 27 olive oil samples were obtained from nine olive mills in Jordan. The levels of PAHs and OCPs were evaluated by gas chromatography coupled with mass spectrometry detector. Among the studied pesticides, only 4,4-Dichlorodiphenyldichloroethylen (4,4-DDE) was found in the tested samples. The estimated average dietary intake (EADI) and hazard risk index (HRI) were then assessed for the 4,4-DDE. The estimated HRI value of 4,4-DDE was less than 1, thus indicating no health risk to consumers. Regarding PAHs, the average concentration of 16 PAHs in the tested olive oil was 36.5 µg/kg. Health risks due to PAH contamination were estimated by determining the dietary daily intake (DDI) and toxic equivalent quotient (TEQ). The values ranged from 0.139 × 10-2 to 7.70 × 10-2 and 0.01 to 0.57 µg/kg for DDI and TEQ, respectively. Light PAHs were predominant in the samples, while no heavy PAHs were detected. The incremental lifetime cancer risk (ILCR) was estimated, and the values ranged from 0.1 × 10-7 to 5.62 × 10-7, and none of the olive oil samples exceeded the limit value of 10-6, thus indicating insignificant potential risk.

Determination of Pesticide Residues in Olive Oil Using QuEChERS Extraction and Liquid Chromatography–Orbitrap High-Resolution Mass Spectrometry: Comparison of Different Clean-Up Sorbents and Validation Study

The aim of this study was the optimization of the clean–up step in the widely applied QuEChERS method for the determination of 39 representative multiclass pesticides in olive oil with Ultra-High-Performance Chromatography–Orbitrap Mass Spectrometry (UHPLC-Orbitrap-MS). The analytical methodology combines the original version of QuEChERS extraction with two different clean-up-step approaches, using firstly a combination of Z-Sep+, PSA and MgSO4 and secondly EMR-lipid. The methods were compared for their efficiency in the removal of fats and co-extractives and their effect on the analytical performance characteristics. Both methods were evaluated in terms of linearity, matrix effects (ME), recovery, precision, limits of detection (LOD) and quantification (LOQ) and expanded uncertainty in three spiking levels of 30, 100 and 300 μg/kg. The recoveries ranged between 70–113% for 95% of analytes (RSDr < 14%) when EMR-lipid was used as a sorbent, while in the case of Z-Sep+/PSA/MgSO4 recoveries ranged between 72–107% for 92% of analytes (RSDr < 18%). ME showed low signal suppression for 77% of analytes in the case of Z-Sep+/PSA/MgSO4 and for 85% of analytes in the case of EMR-lipid. According to the results, both methodologies provided good analytical performances fulfilling validation criteria; however, the EMR-lipid sorbent showed better clean-up capacity (i.e., less matrix effects and lower variability in extraction recoveries) and validation parameter values for more analytes. The validated method was successfully applied to 30 olive oil samples from different regions of Greece. No residues have been identified in the analyzed samples.

Deep eutectic solvent-based clean-up/vortex-assisted emulsification liquid-liquid microextraction: Application for multi-residue analysis of 16 pesticides in olive oils

A new hydrophobic deep eutectic solvent (DES) composed of thymol and vanillin (1:1) was prepared and used as the extraction solvent in vortex-assisted emulsification liquid-liquid microextraction of 16 pesticides in olive oil before GC-μECD analysis. Due to the complexity of oil samples, a DES-based liquid-liquid solvent system (n-hexane/acetonitrile/DES) was developed to achieve an effective clean-up. Among the four examined hydrophilic DESs, [choline chloride]:[urea] led to improved sensitivity, and clean chromatograms with low noise and drift from the sample matrix. Besides, the effect of the significant factors such as extraction solvent volume, pH, ionic strength, and vortex time was investigated. At the optimized conditions, the validation parameters such as linear range 0.04–250 μg kg−1, the limits of detection of 0.01–0.08 μg kg−1, intra-day, and inter-day relative standard deviations (RSDs) < 6.8 and < 9.7%, were obtained. This method was followed by GC-μECD and applied to determine pesticides in five olive oil samples. The relative recoveries were in the range of 63.1–119.4%.

Evaluation of the reproducibility standard deviation in the pesticide multi-residue methods on olive oil from past proficiency tests

The data reported in the frame of proficiency testing (PT) exercises organized from 2007 to 2016 have been statistically re-evaluated using Algorithm A of the ISO 13528:2015, and the relative standard deviation for reproducibility of multi-residue methods for the determination of pesticides in olive oil was evaluated. Usually, the assigned between-laboratories variability in PTs on pesticide residues is fixed/set to 25 %. This value was compared to the calculated robust relative standard deviation (RRSD). A total of 1527 analytical results were collected in the ten PTs for the determination of pesticides in olive oil. An RRSD of 21 % was obtained, below the maximum value of 25 %. If all participants use the same analytical approach (e.g., multi-residue method and same instrumental technique), a lower value of the reproducibility standard deviation should be expecting. The QuEChERS method, coupled with LC–MS/MS and GC–MS/MS, has become an important methodology for the analysis of pesticide residues. This is due to its simplicity, the use of low quantities of acetonitrile, the possibility to analyze a large number of pesticides with fewer steps and high efficiency. This method may harmonize the future of pesticide residue analyses. Recently, it was successfully applied to the analysis of olive oil by 70 % of the laboratories participating to our last PT exercise. An expanded uncertainty of 50 % was systematically applied in Europe since 2006 for the analyses of pesticides; the use of the QuEChERS methodology may reduce to 40 %. This work could contribute to promote the comparability of measurements of pesticide residues in foodstuffs.

Organophosphorous Pesticide Detection in Olive Oil by Using a Miniaturized, Easy-to-Use, and Cost-Effective Biosensor Combined with QuEChERS for Sample Clean-Up.

Herein, we report a portable electrochemical biosensor based on butyrylcholinesterase (BChE) immobilized on carbon black (CB)-modified screen-printed electrodes (SPEs) for the detection of organophosphorous pesticides in olive oil. The BChE/CB-SPE biosensor was developed to detect paraoxon in standard solutions as well as in olive oil samples previously treated with the QuEChERS method to extract pesticides from the whole fatty matrix. The biosensor shows a linear concentration range of between 20 and 100 ppb for paraoxon both in standard solutions (phosphate buffer 0.05 M) and in olive oil extracts, with a detection limit of 6 ppb in olive oil extract, corresponding to 10% of inhibition. The accuracy of this biosensor in olive oil samples was assessed with olive oil spiked with paraoxon, obtaining satisfactory recovery values.

Determination of polar pesticides in olive oil and olives by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry and high resolution mass spectrometry

This article reports the development of two HPLC-MS methods for the determination of polar pesticides in olive oil and olive samples by hydrophilic interaction liquid chromatography (HILIC) separation followed by mass spectrometry detection with tandem mass spectrometry using a triple quadrupole instrument operated in multiple reaction monitoring mode (HILIC-MS/MS) or electrospray time-of-flight mass spectrometry (HILIC-TOFMS). The selected polar pesticides included in the study were: amitrol, cyromazine, diquat, paraquat, mepiquat, trimethylsulfonium (trimesium, glyphosate counterion) and fosetyl aluminium. The simple sample treatment procedure was based on liquid partitioning with methanol. The performance of the sample extraction was evaluated in terms of recovery rates and matrix effects in both olive oil and olives matrices. The results obtained for olive oil were satisfactory while, due to the high complexity of olives, poor recovery rates were obtained for the extraction of diquat, paraquat and amitrol, although with a reasonable precision enabling its use in routine analysis. Similarly, matrix effects were minor in the case of olive oil (ca. 20% suppression average), while significantly higher suppression was observed for olives (30–50% suppression average). The studied approaches were found to be useful for the determination of the pesticides studied in olive oil and olives with limits of quantitation below 5µgkg−1 in most cases when tandem mass spectrometry was used, thus being in compliance with MRLs set by current EU regulation.

Analysis of Pesticides in Olive Oil Using a Modified QuEChERS Method with LC-MS/MS and GC-MS/MS

A simple and high-throughput screening method for the analysis of pesticides in olive oil is presented. A modified QuEChERS sample preparation method was developed to improve the extraction recovery of highly lipophilic pesticides. The acetonitrile extract of the olive oil was directly injected to LC-MS/MS, while other GC-amenable compounds were treated with the modified QuEChERS procedure for GC-MS/MS analysis. The method is an extension of the LIB 4517 to include olive oil. The average recoveries for 80 pesticides quantified by LC-MS/MS at 200, 500, and 1000 ng/g fortifying levels were 91% or better (RSD &lt; 5.5%), while GC-MS/MS analysis demonstrated 81% or better (RSD &lt; 7.2%) for average recovery from 59 compounds at the same spike levels. This method showed an improved recovery of several challenging lipophilicpesticides in olive oils.

Internal quality control as a tool for planning a robustness study regarding a multiresidue method for pesticides found in olive oil

The implementation of the internal quality assurance program allows for demonstration of the performance characteristics of a method, as well as the avoidance of erroneous results. There is increasing concern in testing laboratories to ensure that the analytical process remains stable, giving reliable results under statistical control. Robustness is tested by introducing variations in experimental conditions and examining the effects on the results. The European document SANCO/12495/2011, “Method validation and quality control procedures for pesticide residue analysis in food and feed”, defines robustness as a parameter that can be derived from ongoing method verification. Internal quality control tools, such as the recovery control chart, were employed in this study to enhance the stability of the recovery rates and to investigate the experimental conditions that have a major influence on the quantification of recovery rates. The method investigated in this study permitted us to investigate eighteen pesticides in olive oil by using a gas chromatography–mass spectrometry technique. This method has been accredited to ISO/IEC 17025:2005 standards and was applied for 1 year in routine conditions for pesticide residues at the Italian National Reference Laboratory. The recovery control chart has showed that all recovery rates for 1 year were close to the maximum limit (120 %) of recovery performance criteria. Consequently, a “positive” bias has affected all data over longer periods of time. A robustness test was planned in order to investigate the grounds that most influenced the variability of the results. The robustness test involved the following three parameters: solvent used to dissolve the final extract, internal standards, and type of olive oil.

Sol–gel immobilization of acetylcholinesterase for the determination of organophosphate pesticides in olive oil with biosensors

This paper presents the construction of amperometric biosensors for the detection of organophosphorus insecticides widely used in the treatment of olive trees. The systems are based on the immobilisation of acetylcholinesterase on screen-printed electrodes by bioencapsulation in a sol–gel composite. The enzyme activity was estimated by measuring the thiocholine produced by the enzymatic hydrolysis of the acetylthiocholine chloride using cobalt phtalocyanine as mediator. The developed devices have been used to carry out inhibition studies with three pesticides: malathion, methidathion and dimethoate (in their oxidized form), and tested using standard solutions and real samples of olive oil. These biosensors showed good operational stability as they maintained their initial analytical signal response during 10 successive measurements, and a good reproducibility with a relative standard deviation of 3%. The limits of detection of the developed devices were very compatible with the maximum residue limit tolerated by international regulations, they were as low as 10−9 M for the widely used pesticide malaoxon(oxidized malathion). The developed sensors were successfully used for the determinations of insecticides in real samples of olive oil.

New Immunosensors Operating in Organic Phase (OPIEs) for Analysis of Triazinic Pesticides in Olive Oil

AbstractSeveral tests were carried out on the possibility of fabricating immunosensors working in organic solvents or solvent mixtures and aimed at developing new immunosensors for the analysis of triazinic pesticides present in hydrophobic matrices such as olive oil. Initially, an immunosensor for atrazine was tested in which a hydrogen peroxide electrode was used as transducer and peroxidase enzyme as marker. The competitive process took place in a chloroform–hexane 50 % (V/V) mixture, while the subsequent enzymatic measurement was performed in an aqueous buffer solution. A linear response of between about 50 nM and 5.0 µM was obtained versus atrazine in presence of oil. Subsequently, attempts were also made using a Clark electrode as transducer and performing not only the competition but also the final enzymatic measure in organic solvent. The latter enzymatic measurement was thus carried out in several different organic solvents, such as decane, hexane, chloroform and chloroformhexane mixture. The best analytical results were obtained using decane as solvent and tert‐butylhydroperoxide as substrate of the enzymatic reaction.

Photodegradation of phytosanitary molecules present in virgin olive oil

In recent years, traces of active ingredients from phytosanitary products and other products used in treating olive trees have been found in some olive oils because production systems are unable to separate and/or eliminate these chemical residues. Degradation of five phytosanitary chemicals (methyl parathion, ethyl parathion, chlorpyrifos, methyl chlorpyrifos and oxyfluorfen) in virgin olive oil exposed to ultraviolet light at different temperatures has been studied. The influence on the quality parameters of treated virgin olive oil and its composition has been analyzed. The photodegradation kinetics can be described by a first-order degradation curve. The half-life values determined at the end of a 150-min UV irradiation ( T = 288 K) were as follows: methyl parathion 60.3 min, ethyl parathion 73.0 min, chlorpyrifos 110 min, methyl chlorpyrifos 86.6 min and oxyfluorfen 239.0 min. After the treatment, the phytosanitary chemicals were still present at 19.6, 24.1, 39.1, 32.8, and 67.3% of their initial concentration, respectively. The activation energy for each pesticide was calculated obtaining the following values under the experimental conditions: methyl parathion 15.5 kJ mol −1, ethyl parathion 29.7 kJ mol −1, chlorpyrifos 23.5 kJ mol −1, methyl chlorpyrifos 16.0 kJ mol −1, and oxyfluorfen 157.9 kJ mol −1. These results reinforce photodegradation as an effective tool for the degradation of pesticides in olive oil.

Pesticide residue assessment in different types of olive oil and preliminary exposure assessment of Greek consumers to the pesticide residues detected

In this study the occurrence and levels of multi-class pesticides in different types of virgin olive oil quality and origination were determined and the contribution of olive oil in the chronic risk of pesticide residues consumption in the Mediterranean diet was estimated. For this purpose, a multiresidue method for the determination of 35 pesticides in olive oil was evaluated and applied to a total number of 100 olive oil samples. Ten percent of the samples produced from fruits of conventional cultivations contained no detectable residues whereas in the rest samples were detected residues of 20 insecticides. The highest detection rates were observed for the residues of fenthion, dimethoate and endosulfan. The highest occurrence and levels of pesticides were observed in extra virgin olive oil whereas results pointed that residues in olive oil from variety of olives with high oil yield may be higher. Furthermore, olive oil from organic cultivations could be contaminated with pesticide residues and/or contain low levels of pesticide residues that are not registered for use in olive cultivations. For there were multiresidues of pesticides present in olive oil, there is no zero risk in consumption of olive oil. However, the exposure of olive oil consumers to each detected residue is far below the acceptable daily intake (ADI).

Development of an immunosensor based on the measurement of fluorescence

Consumers concern about the presence of pesticides in food is increasing. However current techniques for detecting pesticide residues in olive oil are very expensive and slow, which make them difficult to apply in commercial conditions. For this reason, the Instituto Valenciano de Investigaciones Agrarias (IVIA) and Universidad Politecnica de Valencia (UPV) have decided to develop an immunosensor as an alternative, fast and cheap method to measure the concentration of some pesticides in olive oil. This work shows the developed transducer by IVIA based on a photovoltaic sensor that transforms the fluorescent radiation to an electrical signal. The immunosensor is based on an immunologic reaction which causes fluorescence on the sample. The intensity of the fluorescence is related with the concentration of marked antibodies. The performed tests with two types of immunoassays and fluorescent markers (FITC and ELF97) have demonstrated the robustness and reliability of the developed transducer. The immunosensor is able to discriminate different concentrations of marked antibodies. This study has demonstrated the possibility of applying this immunosensor to detect chemical residues from pesticide treatments in olive oil samples. These results validate the sensor for future commercial applications.

Application of Gas Chromatography Coupled to Triple Quadrupole Mass Spectrometry for the Multiresidue Analysis of Pesticides in Olive Oil

A new multiresidue method has been developed and validated for the simultaneous determination of 100 pesticide residues in olive oil. The determination of pesticide residues was carried out in only 19 min by gas chromatography coupled to tandem mass spectrometry using a triple quadrupole mass analyzer. The mass spectrometer was operated in electron ionization and the selection reaction monitoring mode was used, acquiring two or three fragmentation reactions per compound. Two extraction processes were studied, and an evaluation of the stability and sensitivity of the chromatographic system has been performed for the tested extraction procedures. The final proposed methodology was based on a liquid-liquid partition with an n-hexane/acetonitrile mixture followed by a gel permeation chromatography cleanup step. An adequate lineal relation was obtained in the studied concentration range (10-200 microg kg (-1)); the recovery values were in the range 70-110% for the two levels of concentration studied: 12 and 50 microg kg (-1). Precision values, expressed as relative standard deviation, were lower than 18% at the aforementioned spiking levels; detection limits, confirmation limits, and quantitation limits were below or equal to 1.9, 2.6, and 3.6 microg kg (-1), respectively. The developed methodology was applied to the analysis of pesticide residues in real samples of olive oil from the south of Spain.

Application of high-performance liquid chromatography–tandem mass spectrometry with a quadrupole/linear ion trap instrument for the analysis of pesticide residues in olive oil

This article describes the development of an enhanced liquid chromatography-mass spectrometry (LC-MS) method for the analysis of pesticides in olive oil. One hundred pesticides belonging to different classes and that are currently used in agriculture have been included in this method. The LC-MS method was developed using a hybrid quadrupole/linear ion trap (QqQ(LIT)) analyzer. Key features of this technique are the rapid scan acquisition times, high specificity and high sensitivity it enables when the multiple reaction monitoring (MRM) mode or the linear ion-trap operational mode is employed. The application of 5 ms dwell times using a linearly accelerating (LINAC) high-pressure collision cell enabled the analysis of a high number of pesticides, with enough data points acquired for optimal peak definition in MRM operation mode and for satisfactory quantitative determinations to be made. The method quantifies over a linear dynamic range of LOQs (0.03-10 microg kg(-1)) up to 500 microg kg(-1). Matrix effects were evaluated by comparing the slopes of matrix-matched and solvent-based calibration curves. Weak suppression or enhancement of signals was observed (<15% for most-80-of the pesticides). A study to assess the identification criteria based on the MRM ratio was carried out by comparing the variations observed in standard vs matrix (in terms of coefficient of variation, CV%) and within the linear range of concentrations studied. The CV was lower than 15% when the response observed in solvent was compared to that in olive oil. The limit of detection was < or =10 microg kg(-1) for five of the selected pesticides, < or =5 microg kg(-1) for 14, and < or =1 microg kg(-1) for 81 pesticides. For pesticides where additional structural information was necessary for confirmatory purposes-in particular at low concentrations, since the second transition could not be detected-survey scans for enhanced product ion (EPI) and MS3 were developed.

Automated determination of pesticide residues in olive oil by on-line reversed-phase liquid chromatography–gas chromatography using the through oven transfer adsorption desorption interface with electron-capture and nitrogen–phosphorus detectors operating simultaneously

A rapid method for the multiresidue analysis of pesticides in olive oil is presented. Pesticides are analyzed by on-line coupling reversed-phase liquid chromatography–gas chromatography using the through oven transfer adsorption desorption (TOTAD) interface with subsequent simultaneous electron-capture and nitrogen–phosphorus detection by post-column splitter. An autosampler is employed and the olive oil is simply filtered before the chromatographic analysis. Organophosphorus, organochlorine and triazine pesticides are determined in one run. The limits of detection are below the required maximum residue levels and calibration curves are linear in the range tested. Repeatabilities (intra-day and inter-days) are good. The method was satisfactory applied to the routine analysis of numerous olive oil samples.

Determination of pesticide residues in olive oil and olives

Pesticide-residue determination in olive oil is becoming a very important and challenging issue. The present article provides a review of the most significant methods for determining pesticides in olive oil. The discussion of sample-treatment procedures is focused on not only the final product (olive oil), but also the direct analysis of the raw material (olive fruits). We outline extraction and clean-up procedures (e.g., liquid-liquid partition, gel-permeation chromatography (GPC), solid-phase extraction (SPE), matrix solid-phase dispersion (MSPD) and Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS). However, we pay specially attention to the clean-up stage, which plays an important role in the whole process. In addition, identification and quantitation of pesticides have been carried out by gas chromatography (GC) coupled to different detectors (flame-ionization (FID), nitrogen-phosphorus (NPD) and electron-capture (ECD), although either GC-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode or GC-tandem MS (GC-MS 2) are becoming the combination of choice, because of higher selectivity and confirmation capabilities. In recent years, the appearance of new, more polar pesticides has prompted the use of liquid chromatography-MS (LC-MS) instead of GC-MS, and we outline its advantageous features for the analyses of polar pesticides in olive oil.

Multiresidue analysis of pesticides in olive oil by gel permeation chromatography followed by gas chromatography–tandem mass-spectrometric determination

A method for the multiresidue analysis of olive oil samples for 26 pesticides is proposed. Residual pesticides are extracted from oil using an n-hexane/acetonitrile mixture, extracts being cleaned-up by gel permeation chromatography (GPC) for analysis by gas chromatography–tandem mass spectrometry (GC–MS/MS). Electron ionization and chemical ionization are employed in a single analysis for the determination of pesticides. Pesticide recoveries from virgin and refined olive oil spiked with 10, 100 and 250 μg/kg concentrations of the pesticides ranged from 83.8 to 110.3%. The proposed method features good sensitivity: its limits of quantification are low enough to allow pesticide residues to be determined at concentrations below the maximum residue levels legally accepted. The precision, expressed as relative standard deviation, ranges from 4.93 to 8.11%. Applicability was tested on 40 olive oil samples. Several pesticides were detected in most of the virgin olive oil samples. By contrast, refined olive samples contained few pesticides, and only endosulfan sulphate was detected in all.

Immunochemical determination of four organophosphorus insecticide residues in olive oil using a rapid extraction process

Sensitive, simple and rapid ELISA methods have been developed for the determination of four organophosphorus pesticides in extra virgin olive oil. The analytical procedure involves simultaneous extraction of the analytes from oil matrix with methanol and a freezing clean-up step (−80 °C), followed by immunoassay determination using standards in matrix. The methodology is specific for diazinon, fenthion, malathion and chlorpyrifos showing little or no cross-reactivity against other organophosphorus compounds. Limits of detection for the pesticides in olive oil are from 46 ng ml −1 for diazinon to 10 ng ml −1 for fenthion, all of them under the established MRLs for olives. The excellent recoveries (between 94 and 122%) obtained by the complete analytical protocol confirm the potential of this approach for detecting these compounds in olive oil, being useful as screening and complementary method in pesticide regulatory and food safety programs. The proposed methodology also correlates well with the reference chromatographic (GC–MS) methods.