Agriculture Reference
In-Depth Information
5.2.5 Analytical Methods
5.2.5.1 GPC Cleanup
GPC column: 360mm
filled with BIO-Beads S-X3; detection wavelength:
254 nm; mobile phase: ethyl acetate
×
25mm,
flow rate: 5.0 ml/min;
injection volume: 5 ml; start collect time: 23min; stop collect time: 60min; online
concentration temperature and degree of vacuum: zone 1: 45
-
cyclohexane (1
+
1, v/v);
C, 33.3 kPa;
°
zone 2: 49
C, 26.6 kPa; termination mode: liquid-level
sensor mode; termination temperature and degree of vacuum: zone 1: 51
C, 29.3 kPa; zone 3: 52
°
°
C, 26.60 kPa;
°
zone 2: 50
C, 23.94 kPa.
°
5.2.5.2 GC-MS/MS with EI Source
Column: DB-1701, 30m
×
0.25mm
×
0.25
μ
m silica capillary column;
the oven
temperature is held isothermally at 40
°
C for 1 min, then increased to 130
°
Cat
30
°
C/min, then increased to 250
°
Cat5
°
C/min, and
finally increased to 300
°
C
at 10
C/min for 5min; carrier gas: helium, purity
99.999%; inlet temperature:
°
200
l; injection mode: splitless injection, purge on after
1.5min; ionization energy: 70 eV; ion source temperature: 200
C; injection volume: 1
μ
°
C; interface tempera-
°
ture: 250
C; solvent delay: 5min; data acquisition mode: multiple reaction monitor-
ing (MRM); quantifying and qualifying ions and collision energies (CEs) of 284
environmental pollutants are given in Table 5.1.
°
5.2.5.3 GC-MS with NCI Source
Column: DB-1701, 30m
×
0.25mm
×
0.25
μ
m silica capillary column;
the oven
temperature is held isothermally at 70
C for 1 min, then increased to 260
Cat
°
°
20
C/min, held for 5min; carrier gas: helium, purity
99.999%; inlet temperature:
°
280
l; injection mode: splitless injection, purge on after
0.75min; ionization mode: NCI, 30 eV; ion source temperature: 230
C; injection volume: 1
μ
°
C; interface
°
temperature: 280
C; reaction gas: methane (CH
4
); solvent delay: 10 min; data
acquisition mode: selective ion monitoring; selective ions and relative abundances
of endosulfans are given in Table 5.2.
°
5.2.5.4 LC-MS/MS
Column: AtlantisT3,
T3, 3
C; mobile
phase: 0.1% formic acid (A), 5mmol/l ammonium acetate (B), and acetonitrile (C);
μ
m, 150mm
×
2.1 mm; column temperature: 35
°
flow rate: 0.2ml/min; injection volume: 20
μ
l; the elution steps of positive ion mode
are as follows: 0
-
3min isocratic at 90% A, 3
-
4min linear gradient from 90 to 20%A,
4
-
12min isocratic at 20% A, 12
-
12.1min linear gradient from 20 to 90% A,
12.1
10 min
isocratic at 90% A; ion source: ESI; scan mode: positive/negative ion scan; ion spray
voltage: 5500V; nebulizer gas pressure: 0.076MPa; curtain gas pressure: 0.069MPa;
-
20min isocratic at 90% A; the elution steps of negative ion mode are 0
-
