Direct Determination of Paraquat, Diquat, Mepiquat

Direct Determination of Paraquat, Diquat, Mepiquat, Morpholine, and Chlormequat Pesticides Using Ion Chromatography and High Resolution Accurate Mass Spectrometry Terri Christison1, John E. Madden1, Alex Semyonov1, Jonathan Beck2, and Jeffrey S. Rohrer1. 1Thermo Fisher Scientific, 1214 Oakmead Parkway, Sunnyvale, CA 94085; 2Thermo Fisher Scientific, 355 River Oaks Parkway, San Jose, CA, USA, 95134 Instruments

Figure 1 shows the IC-HRAM spectrometry flow diagram.

Column

Chlormequat

Dionex IonPac CS17, 2 x 250 mm

MSA Gradient Separation

Flow Rate

Alternating polymer graft with carboxylic acid groups

100 µL injection Equilibrate for 4 min at 2 mM MSA, 2 to 6.4 mM (0.1–2 min), 6.4 to 30 mM (2–5 min), 30 to 60 mM (5–7 min), 60 mM (7–9 min), 10 mM (9.0–10 min) 40 mL/min, 10 min run

Eluent Source Separation Temperatures First Detection

IC-MS interface

Column: 40 C; CD Detector: 35 C, Detector compartment: 20 C Parallel Reaction Monitoring (PRM) Results

IC-MS Installation kit, acetonitrile desolvation solvent at 0.23 mL/min delivered by a second auxiliary pump

Figure 3 shows that trimethylsulfonium, morpholine, mepiquat, and chlormequat were chromatographically resolved and diquat and paraquat were resolved by HRAM spectrometry. Table 1 lists the ions of interest with the PRM conditions.

HRAM Spectrometry

0 100

183.0917

-1.6 ppm

98.097 58.066

114.1283

114.1280

-2.6 ppm

Morpholine

70.066 68.050

D8-Paraquat

88.0764

88.0763

-1.0 ppm

0 100

MS Detection

+ESI, 3.5V, HESI II, full scan, Parallel Reaction Monitoring MS/MS (PRM)

Capillary: 425 C, Ion Transfer: 260 C

Full scan

Collision Energy (V)

PRM Window (min)

Trimethylsulfonium (TMS)

C3H9S+

5.18

50

3–6

Morpholine

C4H9NO

4.84

140

3–6

Mepiquat

C7H16N+

6.31

120

3–6

C5H13ClN+

5.91

70

6–9

Table 1. xx

Sheath: 40, Aux: 5, Sweep: 1 Arb

Temperature

Formula

Retention time (min)

0 100

97.5844 96.5797

97.0832

97.0828

-4.2 ppm

185.107 171.092

186.1146

186.1157

+0.5 ppm

TMS

62.019 61.011

77.0043

77.0043

--

50–300 m/z, AGC 1e6, MIT: 100 mS, resolution: 30,000

90 80 70

8.20

NL: 1.25E7 Base Peak F: FTMS + p ESI Full ms2 [email protected] [50.0000-395.0000] MS PRM_10x_grnbns_10ugL+IS_6

Diquat, m/z 184.0990

60 50

PRM

Chlormequat

AGC 2e5, MIT: 100 mS, 30,000 resolution, fixed first mass: 50.0 m/z, NCE 10–140V, inclusions list (Table 1)

40 30

Diquat

C12H12N2+2

8.04

50

6–9

C12H14N2+2 C12H6D8N2+2

8.05

30

6–9

20 10

Paraquat Data Analysis

ISTD d8-Paraquat

8.05

50

0 100

8.12

90

6–9

80 70

Thermo Scientific™ Xcalibur™ software, Thermo Scientific™ TraceFinder™ software

Paraquat, m/z 186.1146

NL: 1.03E7 Base Peak F: FTMS + p ESI Full ms2 [email protected] [50.0000-400.0000] MS PRM_10x_grnbns_10ugL+IS_6

PRM_10x_grn-bns_7 NL: 1.52E6 FTMS + p ESI Full ms2 [email protected] [50.0000-395.0000] 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 73.0290 131.0189 15 85.0289 119.0190 101.0087 10 5 0 60 80 100 120 140 160 180 200 220 240 m/z

143.0188

40 30

90

Base Peak F: FTMS + p ESI Full ms2 [email protected]

E

97.0828

100

40

188.1220

100

SRD-10

Base Peak F: FTMS + p ESI Full

Electrolytic Eluent Suppressor

Conductivity Detector 0.31 µS

Relative Abundance

ms2 [email protected]

trap Waste

70.0658

[50.0000-110.0000] MS 50

10000ppt_mix7_1

0

100

98.0968

50

10000ppt_mix7_1

6.0

7.0

8.0

9.0

0

10.0

60


157.0760

100

50

Base Peak F: FTMS + p ESI Full ms2 [email protected]

100

[50.0000-205.0000] MS

90

10000ppt_mix7_1

NL: 6.61E5

100

G

171.0913

RT: 0.00 - 10.00


NL: 2.15E7 Base Peak F: FTMS + p ESI Full ms2 [email protected] [50.0000-205.0000] MS PRM_10x_pear_IS_2

70 60

[50.0000-210.0000] MS

30

10000ppt_mix7_1

20

0 NL: 2.45E7

0.0


1.0

2.0

3.0

4.0

5.0 6.0 Time (min)

7.0

8.0

9.0

The Thermo Scientific™ Dionex™ SRD-10 device was added (between the Regen Out on the suppressor and the Regen In on the CR-TC trap column) and programmed to turn off the IC pump when the IC suppressor regenerant flow stops for > 5 min. This is to prevent unneutralized (unsuppressed) eluent flowing into the MS.

[50.0000-145.0000] MS 50

10000ppt_mix7_1

0 0.0

1.0

2.0

3.0

4.0

5.0

6.0

Time (min)

7.0

8.0

9.0

180

200

220 m/z

240

260

280

300

320

340

360

378.49091 380 400

10.0

A. Trimethylsulfonium, m/z 77.0426 >62.019 B. Morpholine, m/z 88.0764 >70.0658 C. Mepiquat, m/z 114.1283 >98.0968 D. Chlormequat, m/z 122.0732 E. ISTD d8-Paraquat, m/z 97.0828 F. Diquat, m/z 183.0920 >157.0760 G.Parquat, m/z 186.1157 >171.0913

183.0914

171.0913

NL: 4.44E7 Base Peak F: FTMS + p ESI Full ms2 [email protected] [50.0000-210.0000] MS PRM_10x_pear_IS_2

60 50 40

m/z 184.0990 7.03

Parquat

NL: 1.84E7 Base Peak F: FTMS + p ESI Full ms2 [email protected] [50.0000-400.0000] MS 50000ppt_mix6_1

m/z 186.1146 2

3

4

5

6 Time (min)

7

8

9

10

11

12

 Fast determinations of six quaternary amine pesticides (TMS, morpholine, mepiquat, chlormequat, diquat, and paraquat) in homogenized fruit and vegetable samples were demonstrated by ICHRAM spectrometry.

4. Thermo Scientific Application Note 666, Routine analysis of polar pesticides.

6. SANTE/11813/2017. European Commission, Directorate General for Health and Food Safety, Safety of the Food Chain, Pesticides and Biocides. http://eurl-pesticides.eu (accessed April 28, 2018)

60 50 169.0758170.0836 106.0653 60

70

118.0652

144.0805 143.0728

80 90 100 110 120 m/z 130 140 150 160 170 180 190 200

PRM_10x_pear_50-4ugL_IS_1 2.40E7 100 FTMS + p ESI Full ms2 [email protected] 90 [50.0000-210.0000]

TRADEMARKS/LICENSING © 2018 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific and its subsidiaries. This information is not intended to encourage use of these products in any manner that might infringe the intellectual property rights of others.

185.1069

80 70 60 50 40

30


185.1069

70

0 50

70

171.0913

186.1148

30

20

172.0946

20

10 0 0.0

157.0758

10

Paraquat, 90 80 m/z 186.1146

7.63

Diquat

5. Rajski, et al. Coupling Ion Chromatography to Q-Orbitrap for the Fast and Robust Analysis of Anionic Pesticides in Fruits and Vegetables, J. AOAC., 101(2), 2018.

20

100

10.0


Mass spectrometer

160

30

0

Relative Abundance

100

140

40

40


0

122.0732

120

PRM_10x_pear_50-4ugL_IS_1 1.17E7 100 FTMS + p ESI Full ms2 [email protected] 90 [50.0000-205.0000] 80

50

[50.0000-135.0000] MS 50

157.0758

Diquat, 80 m/z 184.0990

ms2 [email protected] 10000ppt_mix7_1

D

100

Figure 5. Ten-Fold Diluted, QuPPe-Extracted Pear Sample

10

Data Management

80

NL: 7.75E5

F

0

NL: 1.03E7

C

5.0


m/z 122.0733

3. Thermo Scientific Application Note 661, Fast routine analysis of polar pesticides.

118.0652 144.0807 106.0653

0

NL: 1.29E6

B

4.0

2.49

Chlormequat

2. Adams, S., FERA, Ltd. The Analysis of Polar Pesticides by Ion - Exchange Chromatography Tandem Mass Spectrometry; A Tale of Two (and many more) Molecules, NACRW 2016 symposium.

Time (min)

Relative Abundance

Eluent Generator Cartridge (H+)

0

3.0

Mepiquat

1. European Commission, QuPPe Method. http://quppe.eu/ (accessed April 28, 2018)

[50.0000-120.0000] MS 50

Relative Abundance

Makeup Pump (Solvent)

10000ppt_mix7_1

2.0


m/z 114.1280

REFERENCES

380

45

5

1.0

360

50

15


[50.0000-100.0000] MS 50

0 0.0

340

55

10


320

60

20

77.0425

300

65

25

10

A

280

171.0915

80

30

100

260

186.1150

95

35

20

NL: 2.30E7

3.33

185.1071

70

50

NL: 2.52E7

50


 The JM0006 prototype column improved the chromatographic resolution of diquat and paraquat, but more column development is needed.

PRM_10x_grn-bns_10ugL+IS_6 NL: 9.35E6 FTMS + p ESI Full ms2 [email protected] [50.0000-400.0000] 100

85

m/z 88.0762

 TMS, morpholine, mepiquat, and chlormequat pesticides were chromatographically separated, where as diquat and paraquat were resolved by accurate mass spectrometry.

171.0915 183.0915 157.0759

75

60

Figure 3. Chromatograms of ISTD and Six Cationic Pesticides Using PRM Mode

Morpholine

MSA gradient used on the prototype column JM0006

CONCLUSIONS

Figure 4. PRM Chromatograms and Spectra: Resolution of 20 µg/L Diquat from 20 µg/L Paraquat in QuPPe-Extracted Green Bean Sample

100

2.23

1

Paraquat

RT: 0.00 - 10.00

0 100


m/z 77.0426

0 100

50

Table 1. Ions of Interest and PRM Conditions

Add 30 mL of cold methanol (2. In contrast, diquat-paraquat with the carbon isotopic masses within 2 m/z fully coeluted but were easily resolved in MS/MS by HRAM spectrometry. The four pesticides had good accurate mass, between