R² = 0.9889

R² = 0.987

0

10000

20000

30000

40000

50000

60000

70000

80000

0 0.5 1

AU

C

Concentration (ppm)

Effect of ion source on AEEA 1 using UHPSFC

ESI Unispray

R² = 0.9998

R² = 0.9889

0100020003000400050006000700080009000

0 0.5 1

AU

C

Concentration (ppm)

Effect of chromatography on +ve ion ESI of AEEA 1

UHPLC UHPSFC

R² = 0.9921

R² = 0.9859

050000

100000150000200000250000300000350000400000450000500000

0 0.5 1

AU

C

Concentration (ppm)

Effect of ion source on Q1 using UHPSFC

R² = 0.9998

R² = 0.9819

0

2000

4000

6000

8000

10000

12000

0 0.5 1

AU

C

Concentration (ppm)

Effect of ion source on AEEA 1 using UHPLC

ESI Unispray

R² = 0.9995

R² = 0.9687

0

10000

20000

30000

40000

50000

60000

0 0.5 1

AU

C

Concentration (ppm)

Effect of ion source on Q1 using UHPLC

Conclusions

UnisprayTM ion source coupled to UHPSFC for the detection of oilfield additives

Efstathios Andreas Elia1, William Durnie2, Ed Sprake3 and G. John Langley1

1Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton; 2BP Exploration, Sunbury-on-Thames, Middlesex; 3Waters Corporation, Wilmslow, UK

Introduction

Experimental

Results and Discussion

Design of UnisprayTM source

Figure 2. Schematic representation and actual photograph of the UnisprayTM source .

Comparison of UHPSFC to UHPLC

Comparison of ESI and UnisprayTM using UHPLC

Comparison of ESI and UnisprayTM using UHPSFC

Results and Discussion

Figure 5. Comparison of the MS response for the two model CIs using UHPLC with UnisprayTM and ESI.

• Chromatographic separation of six CIs used in the oil industry achieved in 6 min. with no

sample preparation required

• UHPSFC provides a 6-fold increase in sensitivity compared to UHPLC2

– Unispray TM ion source introduces a 6 to 10-fold increase when compared to standard ESI

• A combination of UHPSFC and UnisprayTM could provide a 60 fold increase in sensitivity

compared to using UHPLC with ESI

• Experimentation with the UnisprayTM ion source and different chemistries can provide further

insight into the ionisation mechanism of both ESI and UnisprayTM

1. Elia Efstathios, Durnie William, Langley G. John, Determination of oilfield additives using separation science and mass spectrometry, BMSS Annual Meeting, 2015

2. Lucie Nováková, Alexandre Grand-Guillaume Perrenoud, Raul Nicoli, Martial Saugy, Jean-Luc Veuthey, Davy Guillarme, Ultra high performance supercritical fluid chromatography coupled with tandem mass spectrometry for screening of doping agents. I: Investigation of mobile phase and MS conditions, Analytica Chimica Acta, Volume 853, 1 January 2015, Pages 637-646

References

Figure 3. Combined RICCs of a 10 ppm solution of the model CI formulation and analysed using UHPSFC (A) and UHPLC (B).

Figure 1. Positive ion ESI mass spectra and chemical structures for each CI used.

• Quaternary amines readily amenable to (+)ve ion ESI due to permanent charge, M+ ion detected

• AEEA imidazolines also easily protonated through the addition of formic acid, [M + H]+ ion

detected

• Full scan mass spectra acquired for concentrations above 1 ppm, SRM spectra acquired for

concentrations below 1 ppm

UHPLC conditions used

Instrument: Waters Acquity UPLC H-class

Mobile phase A: H2O + 0.2% formic acid Mobile phase B: ACN + 0.2% formic acid

Flow rate: 0.7 mL/min. Column: Acquity BEH C18 (100 mm × 3 mm, 1.7 µm)

• The oil and gas industry relies on the use of carbon steel for transmission pipelines which is

susceptible to corrosion

• Use of corrosion inhibitors is the most cost effective means of corrosion mitigation

• Although beneficial to the industry, these additives are toxic and pose a direct threat to aquatic life

• Ongoing need to accurately quantify such additives in trace concentrations in oilfield fluids

• Quantitation of such CIs has been shown to be achieved by direct analysis of crude oil using

UHPSFC1

• A novel ion source (UnisprayTM) was compared to standard ESI source for the trace level detection

of six corrosion inhibitors in various oilfield fluids

Figure 6. Comparison of the MS response for the two model CIs using UHPLC with UnisprayTM and ESI.

Using UnisprayTM ion source with UHPSF is shown to increase the MS response by a factor of 60-

100 when compared to UHPLC with ESI. This is believed to be due to the formation of smaller

droplets in early stages of ESI or the introduction of the impact pin directs more of spray towards

the MS or even that it produces a finer electrospray plume.

C11H23 C13H27 C15H31

C17H35

C17H33C11H23

Mass spectrometer conditions used

Parameters ESI UnisprayTM

Cone Voltage 20 V 20 V

Capillary Voltage 3.3 kV 1.4 kV

Source temp. 150 oC 150 oC

Desolvation temp. 350 oC 350 °C

Desolvation gas flow 700 L/h 700 L/h

Extractor 3 V 3 V

R² = 0.9995

R² = 0.9921

0

10000

20000

30000

40000

50000

60000

70000

0 0.5 1

AU

C

Concentration (ppm)

Effect of chromatography on +ve ion ESI of Q1

Q1 Q2 Q3

Q4 AEEA1

AEEA2

Q1

Q2 Q3

Q4

AEEA2

AEEA1

Figure 4. A comparison of the ESI response of two CIs using UHPSFC and UHPLC.

One quaternary amine and one imidazoline were chosen as model CIs to perform all statistical analyses

on. The observations below are true for all other CIs in the formulation.

Q1

Q2

Q3

Q4

AE

EA

2

AEEA1

A B

UHPSFC conditions used

Instrument: Waters Acquity UPC2

Mobile phase A: scCO2 Mobile phase B: MeOH + 2% H2O + 50 mM NH4OAc

Flow rate: 1.5 mL/min. Column: Acquity HSS C18 (100 mm × 3 mm, 1.8 µm)

Acknowledgements

Q1 Q2 Q3

Q4 AEEA1

AEEA2

Figure 3. Positive ion UnisprayTM mass spectra for each CI used.