**Acknowledgements**

*Gas Chromatography - Derivatization, Sample Preparation, Application*

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Vol injected(μl) <sup>×</sup> Std conc (ng) \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Wt of the sample(g)

In QuEChERS method the use of acetonitrile has several advantages, mainly addition of salt separates it from water without using nonpolar solvents, mutual compatibility with dispersive solid-phase extraction and very good separation/ matching with gas and liquid chromatography. The anhydrous MgSO4 tends to form lumps. Shaking the tubes of the centrifuge on adding the salt mixture for 1 min or more, it was observed that the formation of lumps was eliminated. Next, adding the salt to all of the samples, it was also found that the one-minute extractions of the entire batch could be run parallelly. Dispersive solid-phase extraction with primary secondary amine eliminated the color pigments, acidic components and sugars [10, 11]. Apart from this, sugars, lipids and waxes were removed by freezing which

Grape samples were collected from farmers' fields in Vijayapura district in Karnataka. These areas are very popular for the production of grapes, and we see an excessive use of pesticides. The developed analytical method was used for the determination of residues of pesticides in grape samples and that were analyzed in triplicate. The results confirmed that the grape samples contained pesticide residues well above the prescribed level, viz. carbofuran, fenvalerate, triazophos, and endrin (**Table 2**). Grapes which were analyzed in the present study mainly contributed to

> **MRLs exceeded samples**

 Carbofuran 9 0.14 0.02 Fenvalerate 6 0.33 0.02 Triazophos 4 0.13 0.01 Endrin 5 0.04 0.01

**Residue content (ppm)**

**EU MRLs (ppm)**

Grapes contaminated with residues of pesticides pose a major health hazard. Therefore we have developed effective method for the detection of contaminated grapes. Hence, for the simultaneous confirmation and quantification of 35 pesticides in grape samples, a mulitresidue method has been developed and validated. For multi-class pesticide residue determination, GC-MS/MS with triple quadrupole analyzer played an important role. Within 22 min of run time, all the closely eluted and co-eluted peaks were separated with higher sensitivity. The two MRM transitions, one for confirmation another for quantification, achieved very good

*Analytical results of grape sample analysis collected from Vijayapura district (n = 100).*

<sup>×</sup> \_\_\_\_\_\_\_\_\_\_\_\_\_\_ 100 Fortification level (2)

Area of std <sup>×</sup> Final vol (ml)

helped in increasing the efficiency of GC analysis [12].

**5. Applicability of the developed method**

the major dietary intakes of the citizens in India.

**Name of the pesticides**

*EU, the European Union; MRL, maximum residue limit.*

Residue

**5.1 Sampling**

**Sl. no.**

**Table 2.**

(ppm) <sup>=</sup> Area of sample \_\_\_\_\_\_\_\_\_\_\_\_\_\_

**104**

**6. Conclusion**

Authors acknowledge the ASIDE, Govt. of India and University of Agricultural Sciences, Dharwad, Karnataka, for providing grants for the establishment of Pesticide Residue Testing and Quality Analysis Laboratory.
