Rapid Generation of Fatty Acid Methyl Ester Profiles using (Direct Analysis in Real Time) DART- Mass Spectrometry

Transcription

1 Rapid Generation of Fatty Acid Methyl Ester Profiles using (Direct Analysis in Real Time) DART- Mass Spectrometry Brian Musselman, Jordan Krechmer, Tim Ng, and Joseph LaPoint IonSense, Inc. 999 Broadway Suite 44 Saugus, MA 196 USA

2 Original Objective Saponification and methylation to prepare samples for GC/MS is a common technique for oil characterization Eliminate the time required for GC/MS analysis in order to facilitate higher throughput oil characterizationutilize DART can acquire MS in seconds thus it made sense to attempt to combine the two technologies

3 First: What is DART? DART is a non-contact surface sampling technique for mass spectrometry or ion mobility spectrometry at atmospheric pressure under ambient conditions. An open-air direct probe that can analyze volatile and involatile materials. The Open Air Ionization method capable of analysis of gases, liquid, solids and materials on surfaces simultaneously or descretely.

4 DART-SVP Ionization Source

5 Transmission Mode DART-SVP Stainless steel mesh screens used as the sampling surface Sample Spotting 5 µl of liquid sample pipetted onto stainless steel mesh screen and allowed to completely dry before analysis

6 DART MS FINGERPRINTS ICT Prague Relative Abundance Relative Abundance ,28 411, , ,31 397,38 63,53 256, ,29 92,81 876,8 214,18 423, ,43 537,53 78,61 85,78 766,65 87, ,18 295,23 311,22 328,25 411,4 268,23 397,38 427,39 443,39 DART MS SPECTRA (POSITIVE ION MODE): DILUTED OLIVE OIL 63,53 577, ,57 638,57 876,8 92,81 465,39 357,3 654,56 493,39 78,61 946,84 792,67 85,78 Courtesy of J. Hajslova, Institute Chemical Technology, Prague, CZ

7 Dilution of the Fish Oil Products Simple Sample Preparation For both of the fish oil products the following preparation was performed before direct MS analysis: The gel capsules were cut open and the liquid fish oil product was collected in a small vial A small aliquot (2 µl) of the fish oil product was diluted in 1 ml of toluene and vortexed for 3 seconds The diluted fish oil product was spotted onto the appropriate mesh support for direct MS analysis

8 Fish Oil in Softgel Products Tablet Content from Label Images and product information accessed on August 6, 211 from:

9 Fish Oil 1 Positive Ion DART-MS C NL: 5.37E6 DART-SVP 1-D Trans Bounty Fish Oil Caplet 2_POS_211727# T: FTMS [1.-1.] Relative Abundance [Cholesterol + H H 2 O]+ Elemental composition search on mass = Theo. Mass Delta (ppm) RDB equiv C 27 H C H O N [Cholesterol + H H 2 O]+ Diglycerides Composition 35 C 45 C Triglycerides NL: 1.39E6 DART-SVP 1-D Trans Bounty Fish Oil Caplet 2_POS_211727#7 SB: T: F [1.-1.] NL: 2.48E5 DART-SVP 1-D Trans Bounty Fish Oil Caplet 2_POS_211727#1 SB: T: F [1.-1.]

10 Relative Abundance Fish Oil 1 Negative Ion DART-MS C 25 C C Negative Ion Mode EPA Elemental composition search on mass = Theo. Mass Delta (ppm) RDB equiv C 2 H 29 O C H O N Elemental composition search on mass DHA NL: 2.12E5 DART-SVP 1-D Trans Bounty Fish Oil Caplet 1_NEG_211729#1 SB: T: F [1.-1.] Composition = Theo. Mass Delta (ppm) RDB equiv C 22 H 31 O C H O N NL: 6.33E5 DART-SVP 1-D Trans Bounty Fish Oil Caplet 1_NEG_211729#5 Composition SB: T: F [1.-1.] NL: 4.91E5 DART-SVP 1-D Trans Bounty Fish Oil Caplet 1_NEG_211729#1 SB: T: F [1.-1.]

11 Fish Oil 2 Positive Ion DART-MS Relative Abundance Elemental composition search on mass = Theo. Mass Delta (ppm) RDB equiv. Composition C 29 H 5 O C H O Vitamin E as alpha-tocopherol No Diglycerides C 35 C 45 C No Triglycerides NL: 4.73E6 DART-SVP 1-D Trans Shoppe Fish Oil Caple 1_POS_211727#1 SB: T: F [1.-1.] NL: 6.11E6 DART-SVP 1-D Trans Shoppe Fish Oil Caple 1_POS_211727#6 SB: T: F [1.-1.] NL: 7.27E6 DART-SVP 1-D Trans Shoppe Fish Oil Caple 1_POS_211727#1 SB: T: F [1.-1.]

12 Fish Oil 2 Negative Ion Mode C EPA NL: 1.25E5 DART-SVP 1-D Trans Shoppe Fish Oil Caple 1_NEG_211729#1 SB: T: F [1.-1.] Relative Abundance C C DHA Elemental composition search on mass = Theo. Mass Delta (ppm) RDB equiv C 2 H 29 O C H O Elemental composition search on mass = Theo. Mass Delta (ppm) RDB equiv C 22 H 31 O C H O NL: 2.3E6 DART-SVP 1-D Trans Shoppe Fish Oil Caple 1_NEG_211729#6 Composition SB: T: F [1.-1.] NL: 2.32E6 DART-SVP 1-D Trans Shoppe Fish Oil Caple Composition 1_NEG_211729#1 SB: T: F [1.-1.]

13 Observation that Free Fatty Acids as [M-H] - were easy to detect with great signal-to-noise

14 Can we simplify oil characterization by leveraging saponification? Hydrochloric acid to saponify oil. 1 1 µl Concentrated HCl was mixed with 1mg of EVOO Heated at 75 C for 35 minutes Sample produced viscous yellow green solution Abandoned this approach due to undesirable solution conditions 1. Mossoba, Magdi M., and John K. G. Kramer. Official Methods for the Determination of Trans Fat. 2nd ed. Urbana, IL: AOCS, Print. 14

15 Can we simplify oil characterization leverage saponification Utilize chemistry from ammonium hydroxide-based method for prep of dairy and cheese fatty acids. 1 Add 1 µl of 58% ammonium hydroxide to 1 mg of EVOO Diluted with 4 µl of HPLC grade water to permit mixing Originally, heated at 8 C and sampled every 5 minutes Temperature was then lowered to 4 C to monitor the reaction better 1. Mossoba, Magdi M., and John K. G. Kramer. Official Methods for the Determination of Trans Fat. 2nd ed. Urbana, IL: AOCS, Print.

16 Step 1 Pipet Diluted Oil onto Screen Spot a 5 µl aliquot of analyte solution using a micropipettor on center cutout on the OpenSpot sample card Liquid sample can be left to dry for offline analysis or run immediately for instant sampling

17 1. Spot 3 µl aliquot of 1% Oil on the OpenSpot Card 3. Insert sample card into the slot on ID-CUBE Source 2. Let sample dry 4. Set the desired heating setting on ID-CUBE control box and press button for instant desorption

18 Utilize a second generation DART ID-CUBE near-instant rapid heating 18

19 Commercial EVOO 1 / High Res MS ColavitaOliveOil_8min_MED_ #11-21 RT: AV: 11 SB: NL: 5.32E6 T: FTMS - p NSI Full ms [9.-1.] Oleic Acid C18H33O2 9 8 Relative Abundance 7 6 Linoleic Acid C18H31O Palmitic Acid C16H31O2 3 Stearic Acid C18H35O

20 MS Instrumentation Thermo Exactive Settings Scan Parameters: Exactive Inlet Parameters: Negative Ion Mode Resolution: High - 5, Fragmentation: None, HCD Gas Off Scan Settings: 1 µ-scan by 25 ms max inject time AGC Target: Balanced (1e6) Capillary Temp: Capillary Voltage: Tube Lens Voltage: Skimmer Voltage: 2 C - 5 V -12 V -25 V For all ID-CUBE experiments the Exactive Spray Voltage was set to 1 kv and the following parameters to zero: Sheath Gas Flow, Aux Gas Flow, Sweep Gas Flow 2

21 Monitor the Reaction over time Relative Abundance NL: 5.31E6 colavitaoliveoil_6min_med_212416#22-3 RT: AV: 9 SB: T: FTMS - p NSI Full ms [9.-1.] NL: 6.14E6 colavitaoliveoil_8min_med_212416#17-2 RT: AV: 4 SB: T: FTMS - p NSI Full ms [9.-1.] MIN NL: 6.58E6 colavitaoliveoil_1min_med_212416#263 RT: AV: 5 SB: T: FTMS - p NSI Full ms [9.-1.] MIN MIN NL: 2.69E6 colavitaoliveoil_4min_med_212416#11-18 RT: AV: 8 SB: T: FTMS - p NSI Full ms [9.-1.] MIN

22 Commercial EVOO 1 EVOO MONITOR REACTION 7 6 INTENSITY 5 Oleic Acid Palmitic Acid Stearic Acid Linoleic Acid TIME (min) 22

23 EVOO 2 EVOO REACTION MONITORING 7 6 INTENSITY 5 Oleic Acid Palmitic Acid Stearic Acid Linoleic Acid TIME(min)

24 Sunflower Oil SUNFLOWER OIL REACTION MONITORING Oleic Acid Palmitic Acid Stearic Acid Linoleic Acid INTENSITY TIME( min)

25 Hazelnut Oil: Still work needed HAZELNUT OIL REACTION MONITORING Oleic Acid Palmitic Acid Stearic Acid Linoleic Acid INTENSITY TIME(min)

26 Fish Oil - Different Acids of EPACourse FishOil_8min_ #9-19 RT: AV: 11 SB: NL: 2.24E6 T: FTMS - p NSI Full ms [9.-1.] C2H29O2 9 8 Oleic Acid C18H33O2 Relative Abundance 7 Palmitic Acid C16H31O2 6 DHA C22H31O Myristic Acid C14H27O

27 Fish Oil - AFISHlittle different kinetics OIL REACTION MONITORING 3 25 Oleic Acid Palmitic Acid Stearic Acid Linoleic Acid DHA EPA INTENSITY TIME (min)

28 What else can we measure: How about Oxidation? EVOO heated at 5 C 3 hour Objective was to oxidize the oil Samples were then tested using the IDCUBE using a Low heat setting

29 EVOO 1 3 hours colavita_5c_3min_ #2-9 RT:.2-.7 AV: 8 NL: 5.16E6 T: FTMS - p NSI Full ms [9.-1.] C 18 H 33 O C16H31O3 Relative Abundance C 16 H 31 O C 16 H 29 O C 18 H 33 O C 18 H 31 O C 16 H 3 O C 18 H 33 O

30 Forget the Container Direct in-situ reaction on the Open Spot card 1% EVOO in Hexane was pipetted directly onto the Open Spot card (3µL) 58% Ammonium Hydroxide was pipetted onto the same Open Spot card (3µL) Open Spot card was run on the low temperature Open Spot card was then removed and more Ammonium Hydroxide was added (3µL) and ran at the low temperature setting again 3

31 1. Spot 5 µl aliquot or powder residue on the OpenSpot Card 2. Let sample dry and then apply ammounium hydroxide solution directly onto sampling spot

32 EVOO 1 1 Relative Abundance 5 1 1st Sample nd Sample rd Sample NL: 1.46E5 EVOO_NH4OH_run5_212419# RT: AV: 36 SB: T: FTMS - p NSI Full ms [9.-1.] NL: 2.7E5 EVOO_NH4OH_run5_212419#15318 RT: AV: 28 SB: T: FTMS - p NSI Full ms [9.-1.] th Sample NL: 1.99E5 EVOO_NH4OH_run5_212419#18-33 RT: AV: 16 SB: T: FTMS - p NSI Full ms [9.-1.] NL: 1.33E5 EVOO_NH4OH_run5_212419#22925 RT: AV: 22 SB: T: FTMS - p NSI Full ms [9.-1.] 25 32

33 Conclusions Direct Saponification in under 1 minutes yields reasonable distribution of fatty acids Fatty acids are detected as the deprotonated molecule by DART Conditions for in-situ saponification need work but promising start Near-instant high throughput Fatty Acid has potential for qualitative analysis in seconds per sample Investigation of quantitative analysis underway requires validation by GC/MS so will take time 33