86
Bull Environ Contam Toxicol (2007) 78:85–89
were extracted in a Soxhlet extractor for 4 hr with 300 mL
of a mixture of hexane–acetone (1:1). The extract of the
grain sample was evaporated completely under vacuum,
was dissolved in hexane (40 mL), and was then exchanged
into acetonitrile (3 · 40 mL) to remove the oil from the
grains. The acetonitrile portion was further diluted with
saline water (2%, 600 mL) and was then partitioned into
dichloromethane (3 · 30 mL).
Cl
Cl
O
C
O
O
F
CH
CN
I
The organic solvent was evaporated (dissolved in)
hexane-acetone (9 + 1) and was subjected to clean up. The
concentrate (5 mL) was subjected to column clean up. The
glass column (1.5 mm · 45 cm) was packed with anhy-
drous sodium sulfate (1g) + neutral alumina (2g) + Florisil
(1g) + anhydrous sodium sulfate (1g). The column was
prewashed with hexane (30 mL). The concentrate was
loaded onto the column and was eluted with a mixture of
hexane–acetone (1 + 1). The eluant was concentrated to
dryness under a rotary vacuum evaporator and made up in
hexane before analysis by GLC.
O
F
Cl
Cl
O
H
C
O
OHC
II
III
Fig. 1 b- cyfluthrin (I), 4-fluoro-3- phenoxybenzaldehyde (II), and
3-(2, 2- dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid
(III)
crop (var Pusa 203) were raised in the fields of Indian
Agricultural Research Institute, New Delhi, following the
good agricultural practices of the region. The plot size was
6 m2 for each replicate. Pigeon pea was grown during
Khariff season, whereas chickpea was grown in the Rabi
season. b-cyfluthrin formulation was obtained from M/s
Bayer India Ltd. for the experimental study. b-cyfluthrin
(Bulldock 025 SC) was applied @ 12.5 and 25 g a.i. ha–1 in
750 L water (Treatment T1 and T2) at 50% pod formation
stage in both chickpea and pigeon pea. The experiment was
performed in triplicate for each crop and a control plot was
kept aside in which no pesticide was applied.
b- cyfluthrin (1g) was dissolved in methanol (30 mL)
and was refluxed with aqueous sodium hydroxide (100 g L–
1, 20 mL) for 2 hr. The reaction mixture was cooled and
extracted with dichloromethane. The crude mixture showed
two products on TLC. Column chromatography over silica
gel, and successive elution with hexane and mixture of
hexane:acetone yielded pure two compounds. 4-fluoro-3-
phenoxybenzaldehyde (Fig. 1, II, Rf 0.28), IR m cm–1
1725(s, C = O); NMR-CDCl3 d: 6.76 (m, 5H, Ar-H, C-5,
C-2¢, 3¢, 4¢, 5¢, and 6¢), 7.52 (dd, J = 2Hz, 2H, C-2, and 4),
7.63 (s, 1H, C-6), C-9.85 (s, 1H, D2O, CHO), m/z 243.
3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarb-
oxylic acid (Farkas acid, Fig. 1, III, Rf 0.13), IR: m cm–1
1780,COOH, 3200 (b, OH); NMR-CDCl3 d: 1.22 (s, 6H, 3
· CH3), 1.72 (s, 1H, CH-C), 2.22 (s, 1H, CH-COOH), 5.65
(s, 1H,C=CH), 10.0(s, 1H, D2O exchangeable), m/z 208.
The quantitative estimation of b-cyfluthrin was carried
The maximum temperature during chickpea crop was
27.2ꢁC and 12.0ꢁC, respectively, with a relative humidity
of 32%. Average sunshine hours recorded was 9.50. There
was no rainfall during the period of study. In the case of
pigeon pea, the maximum and minimum temperatures were
29.8ꢁC and 16.9ꢁC, respectively, with relative humidity of
69%. Average sunshine hours recorded was 5. The rainfall
recorded during the period was 68.6 mm.
out using Hewlett Packard gas liquid Chromatograph series
63
II (model 5890) equipped with Ni
electron capture
detector. The column BP-5 was megabore (12 m · 0.52
mm i.d · 1 l) and was used for the estimation of b-
cyfluthrin in crop samples. Another column [megabore BP-
5 30 m · 0.52 mmi.d · 1 l] of varying length but same
polarity was used, to ascertain the identity of the pesticide.
b-cyfluthrin was determined by HPLC (Merck-Hitachi),
consisting of an L-7100 (computer operated dual pump), an
L-7400 (UV detector), and an L-7200 (Auto sampler). The
column used was Lichrospher, RP-18 (30 cm · 5 lm). The
concentration of b-cyfluthrin was calculated on the basis of
a peak area from the calibration curve. Standard solutions
of different concentrations 0.1, 0.2, 0.5, 1.0, 1.5, and 2.0,
lg mL–1 of b-cyfluthrin were injected in the GLC, and a
calibration curve was drawn by plotting peak area vs
concentration. Each injection was made thrice for all the
Green pod samples of both chickpea and pigeon pea
were collected one hour after application of the pesticide,
and subsequently at periodic intervals of 1, 3, 5,7, 10, and
15 days and grains at harvest. 50-g samples of green pods
and grains were spiked in triplicate at two concentrations:
0.5 and 1.0 lg g–1 level. 50-g representative subsamples of
green pods were extracted with acetone (3 · 50 mL) in a
Waring blender. The extract was concentrated under re-
duced pressure and was transferred to a separatory funnel,
and saline water (10%, 150 mL) was added. The pesticide
was exchanged into organic phase by liquid–liquid parti-
tioning with dichloromethane (3 · 30 mL). The organic
solvent was concentrated under reduced pressure and then
was subjected to clean up. The harvest time grain samples
123