Automating Solid Phase Extraction and Florisil

Clean-up for Organochlorine Pesticides

and PCB Aroclors

by Philip Bassignani Technical Director; Applications lab

Fluid Management Systems Inc.

Methods

• EPA 508.1 • EPA 608 • EPA 8080/8081/8082

Objective •  Develop a completely automated procedure combining

the extraction and clean-up for chlorinated pesticides and PCB Aroclors utilizing Solid Phase Extraction

•  Minimize manual steps to lessen error and maximize limited man hours

Reasons for SPE

•  Reduced solvent •  Reduced glassware •  Simplified procedures •  Automation versus manual protocols =

Reproducibility

Determining Factors •  Extraction sorbent (C18, DVB, HLB, etc)

•  Clean-up Sorbent (Florisil, Silica Gel, Alumina, NH2)

•  Extract drying agent (NaSO4, MgSO4, Diatomaceous Earth)

•  Solvent compatibilities (EtAC, DCM, Hexane, Acetone, etc)

FMS TurboTrace ABN

FMS, Inc. SuperVap w/direct to GC vial

Extraction w/C18 •  Advantages

–  Widespread current usage –  Lower cost compared to DVB/HLB –  Easier/shorted drying times

•  Format –  1 gram sorbent amount to 1 liter sample

•  Ensure adequate matrix retention per unit volume –  25 ml cartridge

•  Sufficient surface area to reduce clogging •  High enough flow rate to maintain smooth sample loading.

C18 Cartridge: Loading of a Dirty Matrix

Clean-up with Floirisil

•  Offers suitability for all OCPs and PCBs – Dieldrin & Endrin

•  Approved in all existing EPA methods •  Great application flexibility (amount, level of

deactivation, elution gradient, etc) •  Can be utilized without the usage of Methylene

Chloride*

Drying Agent •  NaSO4

– Widely used in manual procedures – Can be H2O soluble – Prone to clumping

•  MgSO4 – Wide spread usage of OPP/OPN application – Ultra fine particle size – Greater difficulty than NaSO4 to in lab purify.

Drying Agent

•  Diatomaceous Earth – Silica based – Generally used for extraction drying for PFE – Good H2O removal – Does not clump – Can be easily baked at 500C for easy

purification – Large pellet size allows for smooth inline SPE

flow.

Clean-up Cartridge(s)

•  Packaged into a 6ml SPE format •  1 gram of activated Florisil •  Drying agent can either be packaged in an

independent 6 mls cartridge stacked, or layered in the same cartridge

Clean-up Cartridge(s)

Extract Evaporation

SuperVap 12 position concentrator with direct to GC Vial vessels

Operating Temperature = 35 degrees C Nitrogen Pressure = 5 PSI Final Volume = 1ml

Extraction Procedure •  Condition clean-up Cartridge with elution solvent (10%

Acetone in Hexane) •  Condition C18 Cartridge with elution solvent. •  Nitrogen purge off elution solvent •  Condition C18 cartridge with methanol •  Condition C18 cartridge with H2O •  Load sample across C18 via vacuum •  Nitrogen dry C18 Cartridge

Elution Protocol •  Sample bottle rinsed with elution solvent •  Bottle rinse loaded and eluted across C18 and Clean-up

cartridges, collected into FMS SuperVap concentrator •  Cartridges eluted with additional 20mls elution solvents. •  Cartridges nitrogen purged into SuperVap

Total elution solvent = 45mls of 90:10 Hexane/Acetone

Analytical Platforms

•  Agilent 7890 w/µECD •  Thermo Trace GC, DSQ (MS Confirmation

in live matrices)

Data: IPR

#1

#3

0.0%

20.0%

40.0%

60.0%

80.0%

100.0%

120.0%

#1

#2

#3

#4

RSD

Average

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

1016

1260

11.20%

3.40%

77.90% 93.10%

RSD

Average

Data: IPR

0.0%

20.0%

40.0%

60.0%

80.0%

100.0%

120.0%

140.0%

2.2% 2.0% 2.1% 2.1% 9.8% 6.9% 1.9% 3.1% 2.0% 2.0% 2.6% 2.1% 2.7% 3.7% 2.7% 5.8% 4.1% 3.0% 6.3% 4.5%

106% 105% 99%

111%

100%

76%

101%

92% 95% 100% 94%

102% 111%

103% 102%

84%

104% 104% 100% 100%

RSD

Average

Data MDL

0.000 0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.029

0.015

0.028

0.021 0.027

0.025

0.034

0.046

0.023 0.023 0.019 0.020 0.022

0.019 0.020

0.014 0.019 0.020

0.019 0.020 MDL

Mean

Commercial PT Performance

0 2 4 6 8

10 12 14 16 18

8.449

2.53

7.741 7.505

11.367

7.238

3.894

12.584

5.433

17.662

0

7.873 8.65

12.655

15.128

10.017

16.331

11.445

0

8.674

Result ProficiencyValue

Commercial PT Rank

Conclusions

•  All IPR recoveries within 70%-130% •  Capable of delivering clean blanks and

acceptable MDLs •  Excellent performance in live sample

matrices and blind PT studies •  Complete automation of the entire process

from bottle to GC ready extract.

Questions?