Pesticides in Grape and Wine

Mass Spectrometry in Grape and Wine Chemistry, by Riccardo Flamini and Pietro Traldi 

TABLE 9.2. Maximum Residue Limits of Pesticides on Grapes Registered in Italy2 

The pesticide residues are affected by environmental conditions, such us temperature, wind, rain, and solar irradiance. Consequently, MRLs can vary between countries because of the different climatic conditions. Currently, the EU is working for the harmonization of MRLs for raw food, but no limits are fixed for transformed foods. In Italy, when there is no legal limit for transformed food, the amount of raw food for a transformed food unit (e.g., 1.5 kg of grape to produce 1L of wine) and the incidence of technological process should be taken into account. Unfortunately, in the absence of specific data on changes of the residue occurring with the transformation, the only reference data is the MRL of raw food. Some countries, such as the United States, adopt the same MRL of grape for wine (Cabras and Caboni, 2008). 

triazoles (triadimefon, penconazole, propiconazole, and myclo-butanyl structures are reported in Fig. 9.1) are fungicides widely employed in viticulture to control powdery mildew, molds, and other fungal pathogens. These compounds are classified as acutely toxic. They may affect liver functionality, decrease kidney weights, alter urinary bladder structure, and have acute effects on the central nervous system (Briggs, 1992). Due to their persistence, they may be present in fruit juices and wines. The Italian law fixed their LODs in wine between 100 and 500pg/kg. 

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A wide number of analytical methods are available for the determination of pesticides in grapes and wine. Here we report some of the methods commonly used for the MRL control and for the study of pesticide behavior in field experiments and wine-making. 

Pesticides in grape and wine 279 Polyphenols 163 Postsource decay (PSD) 89 Procyanidins 165,214 Production ion scan 81 Proteins 323 Proton affinity 12... 

The use of LC/MS and GC/MS for multiresidue methods reduces the need for a purification step of grapes and wine extracts and circumvents any possible false positive. A description of MS applications in grape and wine pesticides analysis was recently reported by Flamini and Panighel (2006). 

Cabras, P. and Caboni, P. (2008). Analysis of Pesticide Residues in Grape and Wine, In Hyphenated Techniques in Grape Wine Chemistry, Riccardo Flamini, (Ed.) John Wiley Son, Ltd., pp. 227-248. 

Previously, pesticide extraction procedures from grapes and wine in the multiresidue analysis were carried out with polar solvents such as methanol and acetone (Holland and Malcolm, 1992). To increase the recovery of more polar analytes, the extracts were salted out with NaCl, Na2S04 or MgS04, and then partitioned with non-polar solvents such as CH2C12, petroleum ether, etc (Holland and Malcolm, 1992). 

The grape extract or the wine is then purified by using a dispersive aminopropyl solid-phase extraction. These extraction techniques allow the removal of unwanted substances from grapes and wine such us sugars, organic acids, and other substances interfering in the pesticide quantitation (Anastassiades et al., 2003). 

TABLE 9.7. Retention Times (RT) and Quantification Ions in the GC/MS-SIM Analysis of Pesticides in Grape Extract and Wine Coupled with the QuEChERS Method"... 

A GC/ITMS analysis of propanil, acetochlor, myclobutanil, and fenoxycarb in grape juice and wine is performed by recording signals of the collision-produced ions formed by multiple mass spectrometry (MS/MS) reported in Table 9.9. Data in the table compare the GC/ MS-SIM and GC/MS-MS methods used for analysis of these pesticides in grape juice and wine. The two methods have a similar precision and sensitivity in wine analysis, with IT providing a lower sensitivity in the grape juice analysis. 

The pesticide residues on grapes can be transferred to the must and this can influence the selection and development of yeast strains. Moreover, yeasts can also influence the levels of the pesticides in the wine by reducing or adsorbing them on lees (Cabras et ah, 1987). 

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