pcbs in fish oil pittcon 2008 - agilent | chemical … in...page 1 gc analysis of pcbs in fish oil...

GC Analysis of PCBs in Fish Oil by Direct Injection

Without Any Sample Cleanup

Philip L. Wylie, Ph.D.Sr. Applications Chemist

Agilent Technologies

Pittsburgh Conference, 2008Paper 1120-1

Tuesday, 8:30 am

Background Information

Fish are an excellent source of omega-3 fatty acids (DHA & EPA)

American Heart Association recommends eating fatty fish at least two times per week or taking a daily fish oil supplement

0.5-1.8 g of DHA + EPA /day “significantly reduces deaths from heart disease and all causes”

But fish and fish oil may contain pollutants:

PCBs, PBDEs, PCDDs, PCDFs, & heavy metals

American Heart Association (http://www.americanheart.org/presenter.jhtml?identifier=4632)

Analysis of PCBs in Fish Oil – The Challenges

209 possible PCB congeners

No single-column method separates them all

“Indicator” congeners measured in fish oil are: 28, 52, 101, 138, 153, 180 – can be difficult to resolve from other PCBs

Recommended method uses extraction followed by GC with High Resolution MS $$$$$

Problems when trying to GC fish oil

High boilers stay on column causing:

- carryover

- dramatic shifts in PCB retention times

ECD 1

S/S Inlet

ECD 2

PCM

solenoid valve (off)

restrictor

DB-XLB

DB-200

41.040 psig 20.160 psig

No Cut

The Solution: Agilent 7890A with Deans Switch for Heart Cutting and Backflushing

Solenoid Valve “On” for Heart Cutting

ECD 1

S/S Inlet

ECD 2

PCM

solenoid valve (on)

restrictor

DB-XLB

DB-200

41.040 psig 20.160 psig

Cut to Column 2

Restrictor to back detector

Primary columnDB-XLB

Secondary Column DB-200

Pneumatic connections to the solenoid valve

Deans Switch – One of Agilent’s Capillary Flow Technology Devices

Fish Oil Sample Preparation is “Dilute and Shoot”

7683BAuto-sampler

Dilute 1:10 withisooctane

Transfer to2 mL vial

Fish oil supplementcapsule

AddISTD

Heart Cutting with the Deans Switch to Isolate Target PCBs from Fish Oil Spiked with Aroclor 1260

min6 8 10 1 2 14 1 6 18

Hz

15 0

20 0

25 0

30 0

35 0

EC D 1 A , E C D 1A , F ron t S ign al (C H U A N H O N G F ISH O IL D A T A J AN 20 07\20 07 01 22- P C B \P C B0 2-C A LIBR A T IO N IN IS O - O C T AN E 200 7- 01- 22

min4 6 8 10 12 14 16 18

Hz

500

1000

1500

2000

2500

3000

3500

4000

28 52 101 118 153 138 180Heart Cuts

Column 2: DB-200 P/N 122-2033

Column 1: DB-XLB P/N 121-1232

52 101118

153

138

180

28

GC-FID Chromatogram of Fish Oil with No Backflushing

5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

g

1-µL splitless injection of 10% fish oil without backflushing.GC oven was held at 290 oC for 30 min at the end of the run.

5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

1st Blank run

2nd Blank run

Highlighted areas are backflushed

Deans Switch in Backflush Mode

Backflushing Column (3 min @ 295 oC)

ECD 1

S/S Inlet

ECD 2

PCM

solenoid valve (off)

restrictor

DB-XLB

DB-200

1.000 psig 80.000 psig

New ChemStation Software Makes it Easy to Set Up Backflushing

Setting Up Backflush Method

From a 35-Sample Sequence: Chromatograms 2, 20, & 35 Overlaid

min10 12 14 16

Hz

175

200

225

250

275

300

325

350

375

min14.04 14.06 14.08 14.1 14.12 14.14 14.16 14.18

Hz

220

225

230

235

240

245

250

255

260

Zoom

138

PCBs Spiked at 0.5 ppb Each

At 0.5 ppb, PCB 28 is obscured byan interference in the Fish oil

52101

118

153 138

180

Retention Time Precision Column 1 with and without Backflushing

m in5 .3 5 .4 5 .5 5 .6 5 .7 5 .8 5 .9 6 6 .1

N or m .

0

2 0 0 0

4 0 0 0

6 0 0 0

8 0 0 0

1 0 0 0 0

1 2 0 0 0

1 4 0 0 0

1 6 0 0 0

m in5 .3 5 .4 5 .5 5 .6 5 .7 5 .8 5 .9 6 6 .1 6 .2

N or m .

2 0 0 0

4 0 0 0

6 0 0 0

8 0 0 0

1 0 0 0 0

1 2 0 0 0

1 4 0 0 0

10 Runs with Backflushing

10 Runs without BackflushingRetention times shift ~4-5 secduring 10 runs

Retention Time Precision Column 1 with and without Backflushing –

m in9 .7 9 .8 9 .9 1 0 1 0 .1

N or m .

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

m in9 .7 9 .8 9 .9 1 0 1 0 .1

N or m .

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

PCB 118Heart Cut

PCB 153Heart Cut

With Backflushing

Without Backflushing

Shifting RTs result in PCBs moving out of heart cut window.

From a 35-Sample Sequence: Chromatograms 2, 20, & 35 Overlaid

min10 12 14 16

Hz

175

200

225

250

275

300

325

350

375

min14.04 14.06 14.08 14.1 14.12 14.14 14.16 14.18

Hz

220

225

230

235

240

245

250

255

260

Zoom

138

PCBs Spiked at 0.5 ppb Each

At 0.5 ppb, PCB 28 is obscured byan interference in the Fish oil

52101

118

153 138

180

PCBs 118 & 153 Heart Cut to DB-200 Column – with & without Backflushing

m in1 1 . 4 1 1 . 4 5 1 1 . 5 1 1 . 5 5 1 1 . 6 1 1 . 6 5 1 1 . 7 1 1 . 7 5

N o r m .

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

9 0 0

1 0 0 0 PCB 118 PCB 15310 Overlaid Chromatograms

m in1 1 . 4 1 1 . 4 5 1 1 . 5 1 1 . 5 5 1 1 . 6 1 1 . 6 5 1 1 . 7 1 1 . 7 5

N o r m .

4 0 0

6 0 0

8 0 0

1 0 0 0

PCB 118 PCB 15310 Overlaid Chromatograms

Retention times shift by 2.0 seconds in first 7 runs on the secondary column (DB-200)

With Backflushing

Without Backflushing

Comparing Area Count Stability on Secondary Column for 2 PCBs – With and Without Backflushing

Comparing PCB Area Counts on Column 2 With and Without Backflushing in a 10-Injection Series

0

200

400

600

800

1000

1200

2 4 6 8 10 12 14 16 18 20

Injection number

Raw

Are

a Co

unts

PCB 118PCB 153118 No BF153 No BF

Quantitative Analysis of Indicator PCBs in aReal Fish Oil Sample (Un-spiked)

min10 12 14 16 18

Hz

150

200

250

300

350

400

450

4.6 ppb101

13.7 ppb153 11.2 ppb

13810.9 ppb

180

9.02

9

9.45

7

10.6

7810

.886

11.1

2711

.200

13.1

20

13.9

0614

.106

14.2

3414

.437

14.4

9014

.574

16.6

08

17.6

33

ConclusionsCapillary Flow Technology – Deans switch

- extremely low dead volume- inert- does not leak- tracks oven temperature- easy column installation

Backflushing made easy by the ChemStation softwareCan configure columns to Capillary Flow Devices and easily set pressures/flows – 7890A is extremely versatile!For this application…

- No fish oil extraction – saves time and $- Low column maintenance - saves time and $- HR/MS or HR/MS/MS not needed – Saves ~ $400,000

More than 100 fish oil injections made without inlet or column maintenance

http://www.headington.org.uk/shark/

Thank You

pcbs in fish oil pittcon 2008 - agilent | chemical … in...page 1 gc analysis of pcbs in fish oil...

Documents