ORGANONITROGEN PESTICIDES: METHOD 5601, Issue 1, dated 15 January 1998 - Page 9 of 21 TABLE 3. RECOMMENDED LIQUID CHROMATOGRAPHIC COLUMNS AND CONDITIONS PARAMETER
HPLC COLUMN AND CONDITIONS
Column: Solvent:
C18 Acetonitrile
C18 Methanol
Cyano Acetonitrile
Cyano Methanol
Primary Analysis
Confirmation
Confirmation
Confirmation
NOVA-PAK C18
NOVA-PAK C18
Supelcosil LC-CN
Supelcosil LC-CN
octadecyl
octadecyl
cyanopropyl
cyanopropyl
Length (mm)
300
150
250
250
ID (mm)
3.9
3.9
4.6
4.6
4
4
5
5
2.7
2.7
5.2
5.2
water
water
water
water
2% 1-propanol
none
none
none
TEA-PO4
none
TEA-PO4
TEA-PO4
0.02 M
none
0.02 M
0.02 M
acetonitrile
methanol
acetonitrile
methanol
2% 1-propanol
none
none
none
0
0
0
0
3-95% B
10-80% B
3-60% B
3-95% B
30
30
30
30
linear
linear
linear
linear
5
5
5
5
1.00
1.00
1.00
1.00
ambient(~24)
ambient(~24)
ambient(~24)
ambient(~24)
0.6-0.8
3.5-3.8
0.6-0.8
0.6-0.8
5
30
5
5
acetonitrile
1:3 acetonitrile:H2O
acetonitrile
acetonitrile
Application: Column parameters: Column Stationary phase
Particle size (µm) A
Ligand density
Mobile Phase A: Solvent B
Organic modifier C
Buffer
Concentration (Molarity) Mobile Phase B: SolventD Organic modifier Mobile Phase Program: Initial hold time (min) Program rate Program time (min) Program type Final hold time (min) Flow rate (mL/min) Column temperature ( C) Dwell volume (mL) Injection volume (µL) Injection solvent
A B
C
D
Ligand density (micromole/m2) is a better description of surface coverage than % carbon loading [22,23]. Choice of alcohol modifier is not critical. Percentages may be varied to adjust retention times andpeak shapes for early eluting analytes. Reequilibration time may be shorter with 1-propanol [24-26]. Buffer is very essential for basic analytes such as Formetanate, Carbendazim, and Benomyl [12,27,28]. Formentate is cationic at about pH 7, and its actual elution time is sensitive to small changes in pH and ionic strength of the buffer in mobile phase A. Acetonitrile is the better choice when monitoring compounds at UV absorptions below 210 nm [20,29].
NIOSH Manual of Analytical Methods, Fourth Edition
