Chromatography Applications and Technology

Transcription

1 Using Flow Switching Devices to Improve GC-MS Productivity in Environmental Analyses Andrew Tipler, Jonas Bjorklund, William Goodman and Lee Marotta, Chromatography Applications and Technology Group, PerkinElmer PerkinElmer

2 2 Content A novel reversed Deans heartcutting system for application switching The need The design approach Application to environmental analyses

3 PerkinElmer The Need for Application Switching

4 4 The Need Many labs wish to run more than one application on an expensive and sensitive analytical system such as a GC-MS. To do this, they must either: Purchase more than one system Expensive Requires more bench-space May be under-used Swap columns and conditions Time consuming Prone to mistakes Stresses system Affects sample throughput Application switching offers convenience and ease of use without the significant added cost or increased bench-space requirements of multiple systems.

5 5 The Application Switching Concept Injector 1 Column 1 Flow Switching Device Injector 2 Column 2 Transfer Line Detector

6 PerkinElmer The Design Approach to Application Switching

7 7 Mechanical Switching Valve High thermal mass - causing thermal lag Limited it temperature t limit it restricts ti t application Moving parts may wear and leak Metal surfaces risk of activity Large internal volumes risk of dispersion Causes flow disruption baseline artifacts Vent Vent Input A Input B Input A Input B Output Output

8 8 T-Piece Simple doesn t need many parts Low thermal mass no thermal lag Low dead volumes gives good peak shape Easy to deactivate high inertness Both columns always active possible increase in column bleed and other contamination Output flow rate increased- may yg give problems with the MS Input A Input B Output

9 Pressure Controlled T-Piece Column is deactivated t d by dropping its inlet Input A pressure Simple doesn t need many yp parts Low thermal mass no thermal lag P Low dead d volumes gives good peak shape Easy to deactivate high inertness Only one column is active other is backflushed. No increase in bleed etc. Input B Input A Flow rate into detector only increased slightly good for MS P Sample from active column is split into inactive column loss in effective sensitivity and cross-contamination issues Input B 9 Output t Output

10 10 The Traditional Deans Switch The simple switching of a solenoid valve directs the input flow between two outputs Low dead volumes Low thermal mass No moving gp parts Fast response Inert No disruption to flows Input Input Output t A Output B Output A Output B P P

11 11 The Reversed Deans Switch The simple switching of a solenoid valve directs the output flow between two inputs An input is made inactive by dropping its pressure slightly (e.g. by lowering the pressure at the column injector) No disruption to detector flow Pressure balancing is not so important as long as the Golden Rule is observed: the flow from the active input must be less than the output flow. P P Input A Input B Input A Input B Output Output

12 12 The Swafer Technology Ports 1,2 and 6 are configured according to application Ports 3 and 5 are inputs for switching gas Integrated by-pass restrictor

13 13 Swafer Technology About the same size as a US 5-cent coin Layers are 80µm thick Channels are laser-fabricated to different widths down to 50µm Channels are chemically deactivated Easy to remove and replace Low effective thermal mass holder

14 14 Photos of the Technology

15 15 Demo Animation

16 PerkinElmer Example A Simple HS/GC/MS S Methods

17 17 Example A - 3 Simple Applications on 1 GC/MS PAH Analysis Liquid extraction of liquid or solid matrix Liquid autosampler introduction of extract Thin Film Column Nonylphenol lanalysis Liquid extraction Liquid autosampler introductions of extract Thin film column Trihalomethane Analysis HS Analysis of Water Thick film column

18 18 Requirements PAH to be calibrated between ug/ml Nonylphenol lt to be calibrated between 5 50 ug/ml Trihalomethanes should have a quantification limit of 1.0 pg/ml It should be possible to switch between HS Trap analysis and liquid injection in a sequence automatically unattended.

19 Conditions for PAH Analysis Split/Splitless Injector 30m x 0.25mm x 0.25µm Elite-5MS 27.0 Helium Pressures in psig m x 0.25mm x 1.0µm Elite-1MS TurboMatrix HS-Trap D-Swafer 0.1mm Fused Silica Restrictor Oven 50(1) (5) TurboMass MS

20 20 Software Tool to Aid Method Development

21 PAH Analysis PAH Standard (0.2 ug/ml) 21

22 PAH Quantitative Performance PAH % RSD (n=5) r 2 benzo(b)fluoranthene benzo(k)fluoranthene benzo(a)pyrene indeno(1,2,3-cd)pyrene benzo(ghi)perylene

23 Conditions for Nonylphenol Analysis Split/Splitless Injector 30m x 0.25mm x 0.25µm Elite-5MS 29.5 Helium Pressures in psig m x 0.25mm x 1.0µm Elite-1MS TurboMatrix HS-Trap D-Swafer 0.1mm Fused Silica Restrictor Oven 65(1) (10) TurboMass MS

24 Nonylphenol Performance 24 Nonylphenol STD 4 Nonylphenol STD ug/ml

25 Conditions for Trihalomethane Analysis Split/Splitless Injector 30m x 0.25mm x 0.25µm Elite-5MS 19.0 Helium Pressures in psig m x 0.25mm x 1.0µm Elite-1MS TurboMatrix HS-Trap D-Swafer 0.1mm Fused Silica Restrictor Oven 35(2) (0) TurboMass MS

26 26 Trihalomethane Analysis SIR, 10 ml (H2O), 0.5 ng/ml trihalomethane standard 1,1,2-trichloroethane (IS) Chloroform Bromodichloromethane Chlorodibromomethane Bromoform

27 27 Trihalomethane Analytical Results

28 28 Switching between Liquid and HS Injection

29 Switching between HS and Liquid 13:47:23 14:10: HS Trap run of trihalomethanes standard (1.0 ng/ml) followed by a liquid injection of PAH standard 3. HS Sample injected at 13:47 Liquid sample injected at 14:10 Time difference 23 minutes. Headspace Trap method run time 18.8 min. GC oven cool down and liquid autosampler wash cycles = minutes

30 PerkinElmer Example B US-EPA Methods 8260 & 8270

31 System for Switching Between Methods 8260 and : Determination ti of VOCs by Purge & Trap and GC/MS 8270: Determination of semi-volatiles by liquid injection and GC/MS 31

32 Conditions for 8260 Analysis Split/Splitless Injector 30m x 0.25mm x 0.25µm Elite-5MS 20.0 Helium Pressures in psig Aquatech P&T 20m x 0.18mm x 1.0µm Elite-624 D-Swafer 0.1mm Fused Silica Restrictor Oven: 40(2) (0) (3) TurboMass MS

33 33 Volatiles 8260 Chromatogram 100 % Time

34 4-Bromofluorobenzene (BFB) Tune Evaluation BFB % m/z

35 Example 8260 Calibration Data (5 200 ug/ml) 79.7 Compound 11 name: 1,1-Dichloroethene 1 Compound 32 name: 1,3-Dichlorobenzene 209 RSD% = 2.78 RSD% = 4.33 Response Response 0 ppb Compound 19 name: Dibromomethane RSD% = ppb Compound 36 name: Hexachlorobutadiene RSD% = 6.35 Response Response ppb ppb 0 35

36 Conditions for 8270 Analysis Split/Splitless Injector 30m x 0.25mm x 0.25µm Elite-5MS 30.0 Helium Pressures in psig Aquatech P&T 20m x 0.18mm x 1.0µm Elite-624 D-Swafer 0.1mm Fused Silica Restrictor Oven: 45(0) (0)-6-300(7) TurboMass MS

37 Semivolatile Chromatogram 100 % Time

38 Decafluorotriphenylphosphine (DFTPP) Tune Evaluation DFTPP) % m/z 38

39 Semivolatile 8270 Calibration (10 80 ug/ml) 124 Compound 5: 1,4-Dichlorobenzene RSD% = Compound 50: 4-Nitroaniline RSD% = 6.84 Response Responsee 0 ug/kg ug/l Compound 23: 2 - Nitrophenol 54.8 Compound 67: Butyl benzyl phthalate RSD% = 8.79 RSD% = 7.02 Responsee Responsee 0 ug/l ug/l

40 40 Conclusions The reversed heartcut switching technique based on this micro-channel wafer technology is a highly effective means of switching applications between a single MS as illustrated by these example environmental analyses. The technique reduces the need for multiple instruments to run multiple applications or saves hours of otherwise lost time in venting the detector, exchanging columns, etc. Analytical performance is not significantly affected. The system may also be used, without modification, to backflush late-eluting unwanted sample material from either or both channels to further save time and increase analytical throughput.