336 / 471
and product ion transitions monitored by GC-MS/MS are shown in Table
2014.09D
.
(
c
)
LC-MS/MS analysis.—
(
1
)
LC-MS/MS system
.—An Agilent Series 1200 HPLC system directly coupled to
a 6430 triple quadrupole mass spectrometer equipped with electrospray ionization (ESI) source and
Model G1367D autosampler with a Mass Hunter data processing software system (Agilent Technologies,
Santa Clara, CA, USA). LC separation was achieved on a Zorbax SB-C18 column, 2.1 × 100 mm, 3.5 μm
(Agilent Technologies) or equivalent.
(
2
)
Column
.--Zorbax SB-C18, 2.1 × 100 mm, 3.5 μm, or equivalent.
(
3
)
Mobile phase program and flow rate
.--
See
Table
2014.09E
.
(
4
)
Column temperature
.--40°C.
(
5
)
Injection volume
.--10 µL.
(
6
)
Ionization mode
.—ESI.
(
7
)
Ion source polarity
.--Positive ion.
(
8
)
Nebulizer gas
.--Nitrogen gas.
(
9
)
Nebulizer gas pressure
.--0.28 Mpa.
(
10
)
Ion spray voltage
.--4000 V.
(
11
)
Dry gas temperature
.--350°C.
(
12
)
Dry gas flow rate
.--10 L/min.
(
13
) Monitored ion transitions, collision energies, and fragmentation energies for the 20 pesticides and
chlorpyrifos methyl are shown in Table
2014.09F
; and SRM acquisition parameters by LC-MS/MS for the
precursor and product ion transitions monitored are shown in Table
2014.09G
.
(
d
)
Homogenizer
.—Rotational speed higher than 13500 r/min (report also in
g
-force units; T-25B, Janke
& Kunkel, Staufen, Germany or equivalent).
(
e
)
Rotary evaporator
.—Buchi EL131 (Flawil, Switzerland) or equivalent.
(
f
)
Centrifuge
.—Centrifugal force higher than 2879 ×
g
(Z320; B. HermLe AG, Gosheim, Germany or
equivalent).
(
g
)
Nitrogen evaporator
.—EVAP 112 (Organomation Associates, Inc., New Berlin, MA, USA) or
equivalent.
(
h
)
TurboVap
.
—LV Evaporation System(Caliper Life Sciences, Hopkinton, MA,USA) or equivalent.
Candidates for 2016 Method of the Year
276