Molecularly imprinted polymers for the detection of benomyl residues in water and soil samples

Full Terms & Conditions of access and use can be found at

https://www.tandfonline.com/action/journalInformation?journalCode=lesb20

Journal of Environmental Science and Health, Part B

Pesticides, Food Contaminants, and Agricultural Wastes

ISSN: 0360-1234 (Print) 1532-4109 (Online) Journal homepage: https://www.tandfonline.com/loi/lesb20

Molecularly imprinted polymers for the detection of benomyl residues in water and soil samples

Licia Guzzella, Nadia Casatta, Abdelmalek Dahchour, Claudio Baggiani &

Fiorenzo Pozzoni

To cite this article: Licia Guzzella, Nadia Casatta, Abdelmalek Dahchour, Claudio Baggiani

& Fiorenzo Pozzoni (2019): Molecularly imprinted polymers for the detection of benomyl residues in water and soil samples, Journal of Environmental Science and Health, Part B, DOI:

10.1080/03601234.2018.1473970

To link to this article: https://doi.org/10.1080/03601234.2018.1473970

Published online: 21 May 2019.

Submit your article to this journal

Article views: 5

View Crossmark data

Molecularly imprinted polymers for the detection of benomyl residues in water and soil samples

Licia Guzzella^a, Nadia Casatta^a, Abdelmalek Dahchour^b, Claudio Baggiani^c, and Fiorenzo Pozzoni^a

aWater Research Institute-National Research Council (IRSA-CNR), Brugherio (MI), Italy;^bDepartement des Sciences Fondamentales et Appliquees, Institut Agronomique et Veterinaire Hassan II, Instituts, Rabat, Morocco;^cUniversity of Turin, Torino, Italy

ABSTRACT

Benomyl is a benzimidazol fungicide used against various crop pathogens. Although banned in many countries, it is still widely used worldwide and is listed in different monitoring programs among the substances to be monitored to assess human exposure to pesticide residues. The assessment of benomyl is mainly based on the analysis of the residues of its most important metabolite, carbendazim. Existing methods often lack of selectivity and display a limited perform- ance because of the presence of co-extracted compounds. Molecularly imprinted polymers (MIPs) offer an alternative methodology, adsorbing preferentially those target molecules for which the polymers are specifically prepared. In this study, we optimized the synthesis of a polymer imprinted with benomyl. Tests of specificity recognition showed a good performance for carben- dazim compared with other similar pesticides. The mean recovery of benomyl (measured as car- bendazim) from water samples was estimated to be 90% for MIPs while with real soil samples collected in Morocco the recovery efficiency was 62%. Preliminary tests also suggest that this MIP can implement traditional SPE techniques for assessing benomyl residual concentrations in envir- onmental samples.

ARTICLE HISTORY Received 22 December 2017 Accepted 17 April 2018 KEYWORDS Benomyl; carbendazim;

molecularly imprinted polymers (MIPs); soil samples; water samples

Introduction

Commercially known as Benlate

, benomyl is a systemic fungicide, registered as a systemic foliar fungicide for the control of a wide range of diseases of fruits, nuts, vegetables, turf, ornamentals and field crops.

It acts by inhibiting all the cellular processes dependent upon microtubule forma- tion.

Although less sensitive than fungi, certain mamma- lian functions were also discovered to be altered by benomyl adverse effects, inducing environmental protection agencies to introduce this chemical in various risk assess- ment process.

The principal metabolite of benomyl is carbendazim (methyl

the main responsible for most of the toxicity of benomyl, is in itself a fungicide, used as a pre- and postharvest treat- ment to control fungal diseases on various vegetables, fruits and plants.

It is classified as a mutagen and toxic to reproduction, on the base of adverse effects manifested on mammalian species, soil and aquatic organisms.

Banned in Australia, most of the European countries and in the USA,

it is still produced in different developing countries.

Its excessive and repeated uses in agriculture are raising a growing concern: the 2014 EU monitoring program on pesticide residues on food reports carbendazim presence in about 3% of the food products analysed from 28 coun- tries.

Therefore, the European monitoring program lists carbendazim among the substances to be monitored in

products of plant origin in the coordinate multiannual con- trol program of the European Union for 2017–2019 to ensure compliance with maximum residue levels of pesti- cides and to assess the consumer exposure to pesti- cide residues.

In Morocco, the usage of pesticides has steadily increased, reaching a yearly use of more than 23,000 tons of Plant Protection Products in 2010.

In parallel, Morocco export relevant food commodities to EU countries and USA:

according to 2008 data, Morocco was one of the most important trade partner of fresh vegetables and fruits with the EU.

It is essential to consider that many of the pes- ticides authorized in Morocco cannot be marketed and used in the EU due to the toxicological concerns. As a conse- quence, pesticide residual monitoring activities were acti- vated both by different European authorities

and by Moroccan governmental laboratories, such as the EACCE (Etablissement Autonome de Contr

ole et de Coordination des Exportations) and the LOARC (Laboratoire Officiel des Analyses et Recherches Chimiques).

Indeed, ground- water, surface water and soil monitoring programs for pesti- cide control is one of the main activity of the local environmental agencies.

Benomyl, as most pesticides in general, are present in food and environmental samples at very low concentrations.

Therefore, sample preparation has become a key step of the entire analytical process for the fulfilment of environmental

CONTACTNadia Casatta casatta@irsa.cnr.it IRSA-CNR, via del Mulino 19, 20047 Brugherio (MB), Italy.

ß2018 Taylor & Francis Group, LLC

https://doi.org/10.1080/03601234.2018.1473970

and food legislations.

As a result, in environmental ana- lysis, the improvement of the selectivity during extraction and/or subsequent clean-up of sample extracts is an area of intense research activity.

Solid-phase extraction (SPE) is the most frequently used procedure for trace pollutants preparation in environmental, clinical, biological and food samples.

At this concern, the use of incorporation of molecularly imprinted polymers (MIPs) as sorbents appears as one of the most versatile and promising alternatives, widely used and explored in different fields. MIPs are artifi- cial structures capable of mimic natural recognition entities, with several advantages such as low cost, easy preparation, high stability at pH and temperatures and reusability.

Moreover, their high selectivity and accuracy also lower the detection limits, making them highly appealing in many fields, such as environmental analysis.

MIPs are synthe- tized by means of a polymerization process, which uses a template molecule and a functional monomer for copoly- merization, in the presence of a cross-linking agent and ini- tiator in a porogenic solvent, leading to a highly cross- linked three-dimensional network polymer.

After poly- merization, the template is removed, leaving complementary cavities in dimension and shape similar to the template:

these binding sites, specific for the target used in the synthe- sis, have thus the potential to rebind with the template mol- ecule or with other molecules with similar structure in a strong a selective way. Since their introduction, MIPs evolved including a great variety of organic polymers, poly- mer formats, protocols and synthesis approaches (see

for a review).

In this context, different methods have recently been developed for specifically assessing carbendazim residues in various substrates.

Significant advancement was reported but the need of a sensitive, robust and cost-effective method still remains. The objective of this research was to apply the MIPs technology to this fungicide and to synthetize a poly- mer for the analysis of carbendazim providing an efficient, selective, accurate and cost-effective method for the analysis of trace residues in multiple environmental matrixes. The prepared original MIPs were then evaluated by using tap water and extracting Morocco soils, where the fungicide is widely used.

Materials and methods Reagents

Benomyl, carbendazim and metolachlor were purchased from Dr. Ehrenstorfer GmbH (Germany). Methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) for MIP synthesis were purchased from Merck (Germany), while azobisisobutyronitrile (AIBN) was purchased from Fluka (France).

Solvents (acetone, methanol, toluene, dichloromethane, acetonitrile) used in the different steps of conditioning and extraction cartridges, in the preparation of the standards and in the mobile phase of HPLC were certified for residual pesticide analysis (Carlo Erba, Italy).

MIPS preparation

Imprinted polymers were prepared by bulk polymeriza- tion.

To prepare MIPs by non-covalent imprinting method, MAA was used as functional monomer, EGDMA as a crosslinker, AIBN as an initiator, toluene as a porogen and benomyl as a template. Template (1 mmol), MAA (4 mmol), EGDMA (20 mmol) and AIBN (0.25 mmol) were dissolved into glass vials, using 5.6 mL of toluene. After nitrogen purging (5 min), the solution was sonicated in a water bath for 5 min and allowed to polymerize during 24 h at 60

C into a stoppered glass tube. Bulk polymers were ground and wet-sieved in acetone using 45 and 100

m sieves (Retsch, Germany). The fraction with the appropriate size was collected, washed in a Soxhlet apparatus for 8 h using methanol/acetic acid (90:10 v/v), oven-dried and used for packing solid phase cartridges. The same method with- out the use of template was employed to prepare NIPs (not imprinted polymers).

Chromatographic evaluation of polymer

Polymer powder (

45

m) was suspended in methanol and slurry packed in a 50 mm stainless-steel HPLC column (4.6 mm I.D.). The packing was performed by gradually add- ing the slurry into the column and eluting it with methanol at 100 bar. The column was connected to the HPLC system and equilibrated with methanol until a steady baseline. The pressure in the column was about 90 bar with methanol/

water (50:50 v/v) and the flow rate was 2 mL/min. The retention factors (k) were calculated as

(t

)/t

. A vol- ume of 10

L of the analyte (concentration of 100 mg/L in methanol) was injected and the retention times were recorded at 285 nm with an isocratic flow rate of 1.5 mL/

min.

is the retention time of sodium nitrate 2 mM.

Solid-phase extractions and analytical methods

Empty SPE cartridges were packed with 400 mg of MIPs or NIPs (powder size 45

100

m) between two frits. These MI- SPE (molecularly imprinted solid phase extraction) car- tridges were then conditioned with 6 mL of methanol fol- lowed by 2 6 mL of MilliQ water. Samples were passed through cartridges at a flow rate of 8 mL/min by means of a vacuum pump system. Drying was completed by fluxing air during 30 min using the same vacuum pump.

Dichloromethane (DCM) was used for the washing step.

Analytes were eluted with pure or acidified methanol.

The analysis of pesticides was undertaken by a Diode- Array 1050 HPLC (Hewlett Packard, USA) equipped with an automatic sampler and Luna column (5

m, C18(2), 100 Å, 250 3.0 mm; Phenomenex, USA). The initial mobile phase was water:acetonitrile 60:40 v/v. The following HPLC conditions were used: acetonitrile 100% at 4 min; isocratic at 6 min; acetonitrile 40% at 8 min till to 10 min; flow rate:

0.7 mL/min. For quantitative analysis, the external standard method was used at 285 nm wavelength. The calibration curve was generated using linear regression analysis in a range of concentration from 0.1 to 2

g/mL. The limit of

2 GUZZELLA ET AL.

quantification (LOQ) was determined as the minimum detectable amount of analyte with a signal-to-noise ratio (S/

N) of 10.

Water and soil samples

For water sample analysis, 500 mL of tap water were spiked with 0.1

g of benomyl, the sample was passed through 400 mg MIP-benomyl cartridge, washed with 1 mL of DCM and eluted with methanol. The final extract was reduced to 0.5 mL. Blank water samples were tested to as free pesti- cide samples.

The soil samples were collected in the Gharb area, one of the most important agricultural region of Morocco. After collection, soil samples were air-dried for 48 h, sieved through a 2.0 mm-sieve and kept into amber glass bottles at room temperature until analysis. The soil samples were col- lected from a private plantation: there, an experimental cam- paign was undertaken for monitoring linuron and diuron leaching in undisturbed soil columns. Benomyl and carben- dazim were never used in this plantation for crop treat- ment.

According to the USDA classification of soils,

this area is classified as clayey soil (4.2% sand, 25.2% silt, and 70.6% clay) and can be considered representative of the whole area. The organic matter content of soil samples was 2.1%, the mean pH value 8.73 and the average cation- exchange capacity (CEC) of 42.6 cmol/kg.

Soil extraction

Soil samples (25 g) were extracted with 120 mL methanol in an automated Soxhlet (Buchi B-811, Switzerland), concen- trated to about 5 mL in a Rotavapor, filtered with a 0.22

Spartan

RC 30) and diluted with 50 mL of MilliQ water to evaluate the efficiency of the clean-up step through MIP cartridges. Soil enrichment was obtained adding target pesticides (25

g) dissolved in few mL of MilliQ water to sample soils. Before analysis, soils were kept in dark conditions at room temperature some days to allow soil aging of the added pesticides. In particu- lar, methanol Soxhlet extracts of soil samples were fortified

with 25

g of benomyl and metolachlor in a water solution.

They were concentrated, filtered 0.22

was added until reaching a final volume of 50 mL (metha- nol/water 1:10, v/v). Extracts were then concentrated on MIPs cartridge and eluted. Volume was reduced to 1 mL.

Results and discussion Analysis of carbendazim

Benomyl binds strongly to soil and is scarcely soluble in water. In non-sterile soils, it degrades with a half-life of few days.

Organic solvents, such as methanol, commonly used to extract pesticides from environmental matrices and/or to make up standard solutions, can rapidly degrade benomyl into carbendazim and a volatile compound,

ate; in these conditions, benomyl is completely degraded in few hours.

Depending on the nature of the soils, residual carbendazim has a half-life of about 3 days to 12 months, and it degrades through the formation of another highly toxic components.

For this reason, the residual concentration of the parental compound is usually expressed as carbendazim concentration. Similarly, official guidelines for benomyl residues in food and in the environ- ment are indicated as carbendazim levels.

Consistently, in this study, we will identify and quantify benomyl residues as carbendazim.

Chromatographic evaluation

SPE techniques extract target compounds with the same principles of liquid chromatography analysis, i.e., the use of adsorbent materials as stationary phase. At this purpose, an important value is the retention factor (k

) in water: it is estimated by eluting the analytical columns with mobile phase composed of water:methanol mixtures at different ratios (from 60:40 to 10:90 v/v in this study) and can be determined by extrapolating the curve to a content of zero methanol. Higher log

values indicate a greater affinity of reversed-phase adsorbents towards compounds dissolved into aqueous samples. As shown in

Figure 1. Variation of the retention factor (logkw) of carbendazim varying the percentage of methanol (MeOH) in the water/methanol mobile phase. NIP: not imprinted polymer; MIP: imprinted polymer.

was not linear and could be better described with a quad- ratic relationship. When the percentage of methanol was reduced in the water/methanol mobile phase, the adsorption of MIP increased, as well as the retention time of carbenda- zim. This is due to a higher stabilization of the hydrophobic interaction between carbendazim and the stationary phase as compared to the increase in the mobile phase polarity. The adsorption on MIPs was higher than on NIPs in all cases, with a larger difference when the methanol:water ratio was about 1:1, suggesting this proportion as desirable starting point in this study. A log

value of 3.6 was obtained for MIPs synthetized using benomyl as a template, while the log

for NIPs was 2.9. Present results are higher than those previously calculated for carbendazim with C

columns and similar to those obtained with porous graphitic car- bon columns.

The success of the imprinting process was confirmed using metolachlor as ligand. Metolachlor is a widespread non-triazinic pesticide belonging to the chloroacetanilide herbicide family.

In this case, the curves obtained using imprinted and not imprinted SPE columns were closely superimposable (data not shown), suggesting that MIPs syn- thetized with benomyl are not able to recognize metolachlor, and only weak hydrophobic interactions between the analyte and the MIP stationary phase occurred.

The efficiency of benomyl-MIP was evaluated through the imprinting factor (IF), an index of the imprinting effi- cacy through the comparison to a NIP prepared in the same conditions. The IF is calculated as the ratio between the retention factor

obtained for the same compound with MIP- and with NIP-columns.

This normalization method removes the contributions of nonspecific binding

interactions, leaving a value that can be attributed mainly to the imprinting effect of the monomers in the MIPs. The IF of MIPs prepared with benomyl was 1.80 ± 0.11, reaching the maximum when methanol in the aqueous mobile phase was 50% (IF: 2.00), thus suggesting the effective presence of specific molecular recognition interactions.

Another index of polymer selectivity is the specific select- ivity factor (S), calculated as the ratio between the IF of the target compound (IF

) and the IF of another compound not related to the target (IF

, metolachlor in this case). This par- ameter provides information about the selectivity of the polymer toward the compound of interest due to the pres- ence of imprinted binding sites, neglecting any partition effect due to the bulk of the polymer: the higher it is, the higher the selectivity that can be reached.

Again, the

of the MIP-benomyl obtained with different methanol:water ratios was 1.99 ± 0.12, a value similar to, or even higher than, the

value of a previously synthetized MIP for propa- zine that displayed a good affinity towards triazinic compounds.

SPE affinity tests

On the base of previous chromatographic results of the ben- omyl imprinted polymers, we also focused on their perform- ance in extracting carbendazim from water and soil samples.

We evaluated the recoveries obtained for carbendazim as a comparison with metolachlor, a no target compound. Thus, we packed SPE cartridges with 400 mg (45–100

MIP-benomyl. An aqueous standard solution (60 mL) of car- bendazim and metolachlor, respectively, was prepared at a concentration of 5 mg/L. This solution was loaded 5 mL at a

a b

0 20 40 60 80 100 120

MeOH Carbendazim

MeOH Metolachlor

DCM Carbendazim

DCM Metolachlor

%yrevoceR

1 mL 2 mL 3 mL 4 mL 5 mL 6 mL

0 20 40 60 80 100 120

Carbendazim Metolachlor Carbendazim Metolachlor Carbendazim Metolachlor

MeOH/Water 1:3 MeOH/Water 1:1 MeOH/Water 3:1

Recovery (%)

Eluted (MeOH) Washed (DCM) Not absorbed

Figure 2. Chromatographic evaluation of MIPs. Total recovery of standard solutions after the washing and elution steps (a) and at different methanol:water ratios (b).

4 GUZZELLA ET AL.

time on MI-SPE cartridges without reaching the break- through point. Overall, polymers were loaded with a total amount of 300

g (5 mg/L 60 mL) of each compound.

After loading the standard solution, a washing step using 1 mL of DCM followed by elution steps with methanol were completed.

As shown in

very high for metolachlor (87%), while the organic solvent DCM was not able to extract carbendazim from MIP car- tridges. This result confirms the difference of interactions between the imprinted polymer and its template and between the polymer and other non-template compounds:

the non-specific interactions between the stationary phase and metolachlor were rapidly destroyed by a non-polar solv- ent, such as DCM. One of the most common troubles of SPE extraction procedures is the interference of the matrix within the analysis. Therefore, a washing step before eluting SPE cartridges can be useful to reduce this kind of trouble;

here we propose that, using MIP-benomyl, a washing step with DCM may increase the selectivity of this SPE technique by removing possible interferences of no target compounds from the sample extracts, as previously shown.

Moreover, an elution step with methanol, a polar protonic solvent, showed that a volume of 3 mL is enough to extract the 95%

of carbendazim (Fig. 2a).

Soil samples are traditionally extracted with organic sol- vents (methanol, DCM,

cules are diluted in non-aqueous solutions before the purification steps. To test the efficiency of our polymers on so-prepared samples, a standard of the template was diluted

into solutions with different water/methanol ratios. These solutions were then passed through a cartridge filled with MIP-benomyl (Fig. 2b). When the target compound was diluted into a water/methanol solution 50:50 v/v, MIPs-ben- omyl showed a good affinity for benomyl, with a leakage of about 2%. When the ratio methanol:water increased up to 3:1, losses of the compound reached about 28%, suggesting that polymers imprinted with benomyl are effective in con- centrating and purifying soil extracts in methanol, but after a proper dilution in water.

Analysis in tap water samples

Recovery experiments were performed using tap water.

Preliminary tests confirmed that the 45–100

fraction of the MIPs provided the best recovery efficiency, in agreement with the particle size of others stationary phases employed in commercial SPE cartridges (data not shown). A comparison was undertaken between MIP-ben- omyl and the octadecyl SPE cartridge, a largely utilized sor- bent phase for environmental analyses.

Carbendazim recovery from tap water improved from 83 ± 9.2% to 88.90 ± 7.6% (n

6), using C

and MIP sorbents, respect- ively, even if the difference is not statistically significant (Student’s

test,

.09). Present results are comparable to previous studies, in which Oasis HLB and C

cartridges were used.

Figure 3. Recovery (%) of carbendazim and metolachlor at 0.5mg/mL from soil extracts (a) and at 1mg/g from Morocco soils, before and after MI-SPE (b). Data are represented as means with standard deviation (n¼3). DCM: washing solvent; MeOH and MeOH/AcOH: eluting solvent.

Analysis in soil samples

Figure 3a

shows the results of two series of experiments on soil samples performed in triplicate, test 1 and 2. In both cases, DCM was used as washing solvent, while methanol or acidified methanol as elution solvents. As reported in the figure, once again, metolachlor was extracted entirely using a washing step, while carbendazim was extracted only fol- lowing the elution step. The best recoveries were obtained in the second test, using methanol

methanol:acetic acid 90:10 v/v, as previously suggested:

in this case, recoveries increased from 78 ± 5% (only methanol) to 105 ± 4% of the second test (methanol

methanol:acetic acid 90:10 v/v).

Recoveries were also tested starting from 25 g of soil dir- ectly fortified with 25

(Fig. 3b). To discriminate between the efficiency of the Soxhlet extraction and the efficiency of MI-SPE in purifying and concentrating the soil extracts, HPLC analysis were per- formed on the sample extracts before and after passing them through the cartridges. As clearly demonstrated by the results shown in

efficient for metolachlor (recovery: 81%) than for benomyl (recovery: 60%). However, MI-SPE technique could entirely recover carbendazim (103 ± 4.1%) when methanol acidified with acetic acid was used. In this case, the total recovery of carbendazim from soil samples was 62%. The presence of interferences was further reduced through a clean-up step with DCM that also improved the LOQ; a LOQ of 10

g/kg for carbendazim was achieved for soil samples. Results indi- cates that, while MI-SPE step was very effective into pre- concentrating soil extracts, more efforts are still needed for Soxhlet extraction of benomyl residues from soils.

Conclusion

MIPs imprinted with benomyl were prepared and evaluated both in terms of chromatographic properties and of SPE applications. The analysis of the chromatographic behaviour, the comparison with NIPs and the selectivity for carbenda- zim showed that these polymers could be useful applied as stationary phase to extract and preconcentrate carbendazim residues from aqueous samples and soil extracts. Moreover, this method, based on easily available and low cost materi- als, provides the synthesis of MIPs with a great stability for long-term use. By coupling MI-SPE and HPLC analysis, we propose an alternative analytical method to detect a fungi- cide that is widely spread in Morocco as well as in many developing countries. Using the GC–MS technique, the LOQ of this method could be also further reduced. Future efforts may complete this study for detecting benomyl residues through MIPs in biological matrices, such as fruit juices or vegetables, important commodities of Morocco export.

Funding

This research was funded by the Environmental Security Program, NATO, Brussel, Grant n. ESP.MD.CLG.982626 “Synthesis of molecu- larly imprinted polymers for pesticide residue analyses in agricultural commodities”.

References

[1] European Food Safety Authority. Conclusion on the peer review of the pesticide risk assessment of the active substance carben- dazim. EFSA J.2010,8, 1598.

[2] Enviromental Protection Agency, U. S. Reregistration Eligibility Decision (RED)–Benomyl;2002.

[3] Singh, S.; Singh, N.; Kumar, V.; Datta, S.; Wani, A. B.; Singh, D.; Singh, K.; Singh, J. Toxicity, monitoring and biodegradation of the fungicide carbendazim. Environ. Chem. Lett. 2016, 14, 313–317.

[4] California Environmental Protection Agency. Benomyl – Risk Characterization Document;1999.

[5] European Commission Rsegulation (EU) No 559/2011 of 7 June 2011. Amending annexes II and III to regulation (EC) no. 396/

2005 of the European parliament and of the council as regards maximum residue levels for captan, carbendazim, cyromazine, ethephon, fenamiphos. Off. J. Eur. Union2011,2011, 5–21.

[6] U.S. Environmental Protection Agency.Chemicals Evaluated for Carcinogenic Potential;2015.

[7] European Food Safety Authority. The 2014 European Union report on pesticide residues in food. EFSA J.2016,14, e04611.

[8] European Commission. Commission implementing regulation (EU) 2016/662 of 1 April 2016 concerning a coordinated multi- annual control programme of the Union for 2017, 2018 and 2019 to ensure compliance with maximum residue levels of pes- ticides and to assess the consumer exposure. Off. J. Eur. Union 2016,1185, 1–14.

[9] European Commission. Final Report of a Mission Carried Out in Morocco from 08 to 15 February 2011 in Order to Evaluate Controls of Pesticides in Food of Plant Origin Intended for Export to the European Union;2011.

[10] United States Department of Agriculture.Morocco Citrus Semi- Annual 2016 Report–GAIN Report Number: MO1603;2016. [11] Codron, J.-M.; Adanacioglu, H.; Aubert, M.; Bouhsina, Z.;

Mekki, A. E.; Rousset, S.; Tozanli, S.; Yercan, M. Pesticide Safety Risk Management in High Value Chains: The Case of Turkey and Morocco – Deliverable D16 – FP7-KBBE-2009-3, 146;2012. DOI:10.13140/2.1.2057.2164

[12] Villaverde, J. J.; Sevilla-Moran, B.; Lopez-Goti, C.; Alonso- Prados, J. L.; Sandın-Espa~na, P. Trends in analysis of pesticide residues to fulfil the European Regulation (EC) No. 1107/2009.

Trends Anal. Chem.2016,80, 568–580.

[13] Martın-Esteban, A. Recent molecularly imprinted polymer- based sample preparation techniques in environmental analysis.

Trends Environ. Anal. Chem.2016,9, 8–14.

[14] Kubo, T.; Otsuka, K. Recent progress in molecularly imprinted media by new preparation concepts and methodological approaches for selective separation of targeting compounds.

Trends Anal. Chem.2016,81, 102–109.

[15] Zacs, D.; Perkons, I.; Bartkevics, V. Determination of steroidal oestrogens in tap water samples using solid-phase extraction on a molecularly imprinted polymer sorbent and quantification with gas chromatography–mass spectrometry (GC–MS).

Environ. Monit. Assess.2016,188, 433.

[16] Haginaka, J. Molecularly imprinted polymers as affinity-based separation media for sample preparation. J. Sep. Sci.2009,32, 1548–1565.

[17] Andrade-Eiroa, A.; Canle, M.; Leroy-Cancellieri, V.; Cerda, V.

Solid-phase extraction of organic compounds: a critical review.

Part I. Trends Anal. Chem.2016,80, 641–654.

[18] Cormack, P. A. G.; Elorza, A. Z. Molecularly imprinted poly- mers: synthesis and characterisation. J. Chromatogr. B 2004, 804, 173–182.

[19] Ferrer, I.; Lanza, F.; Tolokan, A.; Horvath, V.; Sellergren, B.;

Horvai, G.; Barcelo, D. Selective trace enrichment of chlorotria- zine pesticides from natural waters and sediment samples using terbuthylazine molecularly imprinted polymers. Anal. Chem.

2000,72, 3934–3941.

6 GUZZELLA ET AL.

[20] Imache, A.; Dahchour, A.E.; Elamrani, B.; Dousset, S.; Pozzoni, F.; Guzzella, L. Leaching of diuron, linuron and their main metabolites in undisturbed field lysimeters. J. Environ. Sci.

Heal. Part B: Pest. Food Contam. Agric. Wastes 2009, 44, 31–37.

[21] United States Department of Agriculture. Soil Survey Laboratory Information Manual – Report No. 45, Version 2.0.

(45);2011.

[22] Mallat, E.; Barcelo, D.; Tauler, R. Degradation study of benomyl and carbendazim in water by liquid chromatography and multi- variate curve resolution methods. Chromatographia 1997, 46, 342–350.

[23] FAO. Joint FAO/WHO Food Standards Programme – Codex Alimentarius Commission–Report of the 48th Session of the Codex Committee on Pesticide Residues REP 16/PR. 2016; pp.

1–133.

[24] Hennion, M. C.; Cau-Dit-Coumes, C.; Pichon, V. Retention behaviour of polar compounds using porous graphitic carbon with water-rich mobile phases. J. Chromatogr. A 1998, 823, 147–161.

[25] Enviromental Protection Agency, U. S. Pesticides Industry Sales and Usage: 2006 and 2007 Market Estimates. U.S.

Environmental Protection Agency;2011.

[26] Jing, T.; Gao, X. D.; Wang, P.; Wang, Y.; Lin, Y. F.; Zong, X. C.; Zhou, Y. K.; Mei, S. R. Preparation of high selective molecularly imprinted polymers for tetracycline by precipitation polymerization. Chin. Chem. Lett.2007,18, 1535–1538.

[27] Spivak, D. A. Optimization, evaluation, and characterization of molecularly imprinted polymers. Adv. Drug Deliv. Rev.2005, 57, 1779–1794.

[28] Cheong, S. H.; McNiven, S.; Rachkov, A.; Levi, R.; Yano, K.;

Karube, I. Testosterone receptor binding mimic constructed using molecular imprinting. Macromolecules 1997, 30, 1317–1322.

[29] Guzzella, L.; Pozzoni, F.; Baggiani, C. Synthesis and character- ization of a propazine imprinted polymer for the extraction of triazines herbicides. Water Sci. Technol.2008,57, 139–144.

[30] Carabias-Martınez, R.; Rodrıguez-Gonzalo, E.; Herrero- Hernandez, E. Behaviour of triazine herbicides and their hydroxylated and dealkylated metabolites on a propazine- imprinted polymer: comparative study in organic and aqueous media. Anal. Chim. Acta2006,559, 186–194.

[31] Dujakovic, N.; Grujic, S.; Radisic, M.; Vasiljevic, T.; Lausevic, M. Determination of pesticides in surface and ground waters by liquid chromatography–electrospray–tandem mass spectrom- etry. Anal. Chim. Acta2010,678, 63–72.

[32] Belmonte Vega, A.; Garrido, F. A.; Martınez Vidal, J. L.

Monitoring of pesticides in agricultural water and soil samples from Andalusia by liquid chromatography coupled to mass spectrometry. Anal. Chim. Acta2005, 538, 117–127.

[33] Berggren, C.; Bayoudh, S.; Sherrington, D.; Ensing, K. Use of molecularly imprinted solid-phase extraction for the selective clean-up of clenbuterol from calf urine. J. Chromatogr. A2000, 889, 105–110.