M.C.Khetagoudar, Mahadev B. Chetti.,* Deepa G.T., P.T.Goroji, Dinesh B.K. Download full-text
Pesticide Residue Testing Laboratory, UAS, Dharwad 580 005, Karnataka, India,
*(Corresponding author's E-mail : email@example.com)
Introduction Validation study
Sl. WindowtR Name ofPrecursor Product Collision Conc.
No. (min) (min) Compounds ion (m/z) ion (m/z)energy(ppb)
Results and Discussion
M Pesticides are widely used to protect the crops from a variety of
pests. The use of pesticides benefits in increasing agricultural
production but the repeated and indiscriminated uses of
pesticides have led to their accumulation in plants, animals and
79 10 50
thus effecting widespread contamination of the environment.
2 10.03 Phorate260
M Application of excess pesticides leads to accumulation of residues
3 10.75 Lindane181145 10 10
which remains on fruits and vegetables, constituting a potential risk
10.7511175 10 10
to consumers. Fruits and vegetables are the foods that receive the
411.03 Chlorothalonil 266 13326 50
highest doses of pesticides.
11.04 266 2311550
5 12-13 12.42 Fenitrothion 277 260550
12.42 206 162 1150
6 12.59 Malathion 173 1275 50
12.58173 9910 50
7 12.73 Chorpyriphos314 25812 50
8 12.81 Fenthion 278 109 1250
12.81278 245 12 50
9 12.84 Aldrin263193 22100
1012.87 Parathion291 10910 50
12.87 29181 3550
1113-1413.66 Phenthoate 2741218 50
12 13.68 Dimethoate1254720500
1313.70 Quinalphos146 1187 10
13.70 15710220 10
1414-15 14.28 A- endosulphan 240.9 205.91050
14.28194.9 124.920 50
15 14.66 4,4-DDE246 17626 10
14.66 248 1762610
16 14.57 Profenfos339269 10100
14.57 337267 10100
1714.80 2,4-DDD 23516516 10
18 15-18 15.18 Endrin26319330 100
15.18 263191 22 100
19 15.38 B- endosulphan195160450
2015.43 Ethion231 1291850
2115.70 Triazophos 257162 10100
15.70161 77 19100
22 17.33 Anilophos 226157 12100
17.33226 1844 100
Table1: Experimental conditions of the optimized GC MS/MS
Linearity - Assumed when regression coefficient was >0.99 with
residuals lower than 30%.
Selectivity - Estimated by considering the absence of interfering
peaks at the RT of each compound and based on the acquisition of two
5-11.56.03 Dichlorvos 185
MS/MS transitions for each analyte by selecting adequate precursor
and product ions.
LOQ - Established as the lowest concentration level validated with
satisfactory values of recovery and precision.
LOD - Estimated as the analyte concentration that produced a peak
signal of three times the background noise in the chromatogram, and it
Control of pesticide residues in food commodities has become a
was obtained by using a software option i.e., S/N ratio, referring this
requirement for compliance with the legislation, ensuring safety of
value to a S/N value of three.
the population and international and national trade.
Multi-residual methodologies capable to determine a large number
of pesticides simultaneously with satisfactory sensitivity and
To improve those methodologies by changing the analytical
selectivity are highly required.
determination using GC-MS/MS with QqQ analyzer, in order to
Combination of GCMS/MS, with ion trap analyzer approach has
improve sensitivity and selectivity, taking advantage of the possibility
been successfully validated for a large number of GC-amenable
of acquiring two MS/MS transitions for each compound.
pesticides in food ,water , soil samples,and etc.
Use of tandem mass spectrometry (MS/MS) with triple quadrupole
(QqQ) analyzer takes advantage of adequate precursor and
Optimization of the MS/MS method was performed for all
product ions selection.
pesticides using hexane standard solutions injected in the EI
Acquiring two transitions leads to a reliable confirmation of the
compound detected in sample.
For full scan spectra of each compound, the base peak of the
spectrum was selected as precursor ion.
Once the precursor ion was selected, different values of collision
Optimization of wide-scope multi-residue method using GC-
energy (between 4 and 40 eV) were tested to study the
MS/MS with QqQ analyzer for the determination of a large number of
fragmentation. The final purpose was to develop a method with two
organochlorines, organophosphorus pesticides.
Table shows the precursor and the product ions corresponding
to the quantitative and confirmative transitions monitored.
Optimum values of collision energy for most compounds were
found to be between 4 and 36 eV.
Retention time of GC-MS/MS chromatograms for OCs and OPs
pesticide reference standards, pesticides have been showed
within a wide range of retention times (5-20 min.) to better illustrate
the performance of the method.
The selectivity of the method was satisfactory and came from the
acquisition of two specific transitions for each pesticide.
GC-MS/MS chromatograms did not show the presence of
Acquisition of two transitions allows the simultaneous
quantification and confirmation of pesticides in only one injection,
as an alternative approach to the proposed elsewhere where one
injection with only one transition is used as a screening method
and a second injection, of only potentially positive samples, is
Fig-1 : A GC system (Agilent 6890N) equipped with an Autosampler
required for confirmation and quantification purposes.
(Agilent 7683) coupled to a Triple quadrupole (QqQ) mass
spectrometer Quattro Micro GC (RAB120 Waters).
GC Column: HP-5MS (30 m L, 0.25 mm i.d, 0.25 ?m
film thickness )
Oven programming: 50 C - 1 min.
25 C/min. - 150
10 /min. - 280 C (holding time 4 min.)
Injection volume : 1 µl
Injector temperature: 250 °C split less time of 1 min.
Carrier gas: Helium 99.999%, at a flow of 1.3 mL/min.
Interface temperature : 250 °C.
Mode: Electron impact, source temperature at
Collision gas: Argon 99.995%.
Dwell time / channel: 0.05 sec .
Reference gas: Heptacosa (perfluorotri-n-butylamine),
Multi-residue method has been optimized for the simultaneous quantification and confirmation of around 22 pesticides.
Potential of GC-MS/MS with triple quadrupole analyzer has shown to be a key tool for the quantitative determination of this high number of
Selection of two transitions, one for quantification and one for confirmation, gives excellent selectivity and sensitivity.
M. I. Cervera & C. Medina & T. Portolés & E. Pitarch &J. Beltrán & E. Serrahima & L. Pineda & G. Muñoz & F. Centrich & F. Hernández. Multi-
residue determination of 130 multiclass pesticides in fruits and vegetables by gas chromatography coupled to triple quadrupole tandem
mass spectrometry, Anal Bioanal Chem (2010) 397:28732891.
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Authors acknowledge ASIDE, Govt. of India and University of Agricultural Sciences, Dharwad, Karnataka, India for financial support.