37 / 302
Analysis of Triazine Pesticides in Drinking
Water Using LC-MS/MS (EPA Method 536.0)
Jonathan Beck, Thermo Fisher Scientific, San Jose, CA, USA
Introduction
The US EPA has recently issued a draft form of a proposed
method for the analysis of triazine compounds in drinking
water.
1
This method uses a simple method to directly analyze
triazine compounds using LC-MS/MS without requiring any
solid phase extraction (SPE) or other lengthy sample
preparation steps. This application note demonstrates the
analysis of these compounds over the concentration range
0.25 – 5.0 ng/mL (ppb) using the Thermo Scientific TSQ
Quantum Access
™
triple stage quadrupole mass spectrometer
and the Thermo Scientific Accela
™
HPLC system.
Experimental Conditions
The following triazine and triazine degradates were analyzed:
Atrazine, Atrazine-desethyl, Atrazine-desisopropyl,
Cyanazine, Propazine, and Simazine, purchased from
Sigma-Aldrich, St. Louis, MO, and Ultra Scientific, North
Kingstown, RI. The following internal standards were used:
Atrazine-d
5
, Atrazine-desethyl-d
7
, Atrazine-desisopropyl-d
5
,
Cyanazine-d
5
, Propazine-d
14
, and Simazine-d
10
, purchased
from C/D/N Isotopes, Inc., Pointe-Claire, Quebec, Canada.
Standards and internal standard stocks were prepared in
solutions of methanol and diluted to their appropriate
concentrations prior to analysis.
Sample Preparation
While no SPE was required for this method, samples were
treated as per the EPA’s draft method. The method calls
for the addition of ammonium acetate at 20 mM for pH
adjustment and dechlorination and sodium omadine at
64 mg/L to prevent microbial degradation, both purchased
from Sigma-Aldrich, St. Louis, MO. All samples were
prepared in reagent water. All samples were spiked with
the internal standard solution, resulting in a final
concentration of 5 ng/mL (ppb) for each internal standard.
Calibration standards were prepared at the following
levels: 0.25, 0.5, 1, 2, 2.5 and 5 ng/mL.
HPLC Conditions
Column:
Thermo Scientific Hypersil GOLD
™
100 x 2.1 mm, 3 µm
Solvent A:
5 mM Ammonium Acetate
Solvent B:
Methanol
Flow Rate:
400 µL/min
Injection Volume:
100 µL
HPLC Gradient:
Time
%A
%B
0:00
98
2
10:00
98
2
20:00
10
90
25:00
10
90
25:06
98
2
30:00
98
2
Mass Spectrometer Conditions
Ionization Source:
Positive Electrospray
Sheath Gas:
30 arbitrary units
Auxiliary Gas:
10 arbitrary units
ESI Voltage:
3.5 kV
Ion Transfer Tube Temperature:
350 °C
Collision Gas:
1.5 mTorr
Q1/Q3 Peak Resolution:
0.7 Da
Scan Width:
0.01 Da
MS Parameters
Precursor
Product
Collision
Tube
Compound
Mass
Mass
Energy
Lens
Atrazine-desisopropyl
174
132
17
90
Atrazine-desethyl
188
146
16
95
Simazine
202
124
17
80
Atrazine
216
174
16
85
Propazine
230
124
17
80
Cyanazine
241
214
15
100
Atrazine-desisopropyl-d
5
179
137
17
85
Atrazine-desethyl-d
7
195
147
17
95
Simazine-d
10
212
137
19
95
Atrazine-d
5
221
179
17
95
Propazine-d
14
244
196
18
95
Cyanazine-d
5
246
219
16
100
Key Words
• Drinking Water
Analysis
• Herbicides
• Hypersil GOLD
Columns
• Triazines
• TSQ Quantum
Access
Application
Note: 434