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Cameron George Technical Support Engineer 26 April 2001 An Optimized Dual Column System for the Analysis of Chlorinated Pesticides, Herbicides and PCBs.

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Presentation on theme: "Cameron George Technical Support Engineer 26 April 2001 An Optimized Dual Column System for the Analysis of Chlorinated Pesticides, Herbicides and PCBs."— Presentation transcript:

1 Cameron George Technical Support Engineer 26 April 2001 An Optimized Dual Column System for the Analysis of Chlorinated Pesticides, Herbicides and PCBs by GC-ECD

2 Cameron George Applications Chemist April 26, 2001 An Optimized Dual Column System for the Analysis of Chlorinated Pesticides, Herbicides and PCBs by GC-ECD 11:00 a.m. EST Telephone Number: Chair Person: Lisa Lloyd

3 Cameron George Applications Chemist April 26, 2001 An Optimized Dual Column System for the Analysis of Chlorinated Pesticides, Herbicides and PCBs by GC-ECD 11:00 a.m. EST Telephone Number: Chair Person: Lisa Lloyd Starts in Five Minutes

4 Cameron George Applications Chemist April 26, 2001 An Optimized Dual Column System for the Analysis of Chlorinated Pesticides, Herbicides and PCBs by GC-ECD 11:00 a.m. EST Telephone Number: Chair Person: Lisa Lloyd Starts in One Minute

5 CLP Pesticides B-0447 March 8, 2001 AREAS OF FOCUS Injector Detector Column (including guard column)

6 CLP Pesticides B-0447 March 8, 2001 TRACE ANALYSIS INJECTION TECHNIQUES pg On-Column Megabore direct Splitless PTV On-Column (cold & hot) Large volume

7 CLP Pesticides B-0447 March 8, 2001 SAMPLE INJECTION Goals Introduce sample into the column Reproducible No efficiency losses Representative of sample

8 CLP Pesticides B-0447 March 8, 2001 Short Concentrated Long Diffuse Solute Bands Same column, same chromatographic conditions INFLUENCE OF INJECTION EFFICIENCY

9 CLP Pesticides B-0447 March 8, 2001 FIRST, SOME BASIC DEFINITIONS: Regarding Inlets Backflash Discrimination

10 CLP Pesticides B-0447 March 8, 2001 A FEW WORDS ABOUT BACKFLASH Definition: In a vaporization injection, a phenomenon wherein a portion of the sample expands beyond the boundary of the injection port liner towards the septum face and incoming gas line

11 CLP Pesticides B-0447 March 8, 2001 BACKFLASH Effects Ghost peaks Erratic quantitation Poor accuracy

12 CLP Pesticides B-0447 March 8, 2001 BACKFLASH Causes Highly volatile solvent Excessive inlet temperature Excessive injection volume Small liner volume

13 CLP Pesticides B-0447 March 8, 2001 BACKFLASH Preventative Measures Lower inlet temperature Less volatile solvent 1-2 µL injection volume Chambered liner Using pulsed split or pulsed splitless

14 CLP Pesticides B-0447 March 8, 2001 Yes NO!!! INJECTION PORT LINERS Splitless

15 CLP Pesticides B-0447 March 8, 2001 INLET DISCRIMINATION Injected sample  Sample into the column Due to compound volatility differences Higher volatility = More into the column

16 CLP Pesticides B-0447 March 8, 2001 INLET DISCRIMINATION In Pesticide Analyses Generally inlet discrimination is not a concern for pesticide analyses when utilizing appropriate GC inlets such as Splitless, Pulsed Splitless and PTV

17 CLP Pesticides B-0447 March 8, 2001 OTHER INLET CONSIDERATIONS Silylation Using glass wool Cleaning and reusing liners

18 CLP Pesticides B-0447 March 8, 2001 A FEW WORDS ABOUT RESIDUES Semivolatile vs nonvolatile Worst offenders Sample prep

19 CLP Pesticides B-0447 March 8, 2001 GUARD COLUMNS Use 0.53mm Or 0.32mm ID Deactivated Tubing Fit all inlets Enhanced deposition of residues Easy to work with Minimum 1 meter

20 CLP Pesticides B-0447 March 8, 2001 Usually 1-5 meters long and same diameter as the column Detector Deactivated Fused Silica Tubing Union Column Injector GUARD COLUMN Traps non-volatile sample residues

21 CLP Pesticides B-0447 March 8, 2001 COLUMN CONNECTORS Thermal Mass, Inertness, Seal Integrity Stainless steel VU-Tight Press-fits Integral guard columns (Duraguard)

22 CLP Pesticides B-0447 March 8, 2001 Let’s Be Sensitive ANALYTE DETECTION

23 CLP Pesticides B-0447 March 8, 2001 The minimum amount of an analyte that can still be confidently identified as a peak (S/N > 4) SENSITIVITY Analytical Definition

24 CLP Pesticides B-0447 March 8, 2001 SENSITIVITY Analytical Definition Detector Sensitivity: No sample influence (standard) Method Sensitivity: Matrix influence (sample)

25 CLP Pesticides B-0447 March 8, 2001 N S N S x "Normal" response 1. High noise, detector, background 2. Absorption, breakdown of analyte 3. Sample prep losses "Improved" response 1. High quality circuit components and reagents 2. Inertness 3. Method optimization RESPONSE TO A CONSTANT ANALYTE AMOUNT 2 Cases

26 HP 6890 Series Micro-ECD Design

27 Comparison of HP 6890 ECDs Standard < > 10^4 no spec Micro-ECD < > 5 x 10^5 > 5 x 10^ pg/sec lindane lindane pg (ppb) Hz MDL Dynamic range Linear range Linear Range, CLP pesticides Maximum data rate

28 CLP Pesticides B-0447 March 8, 2001 Break Number 1 For Questions and Answers Press *1 on Your Phone to Ask a Question

29 CLP Pesticides B-0447 March 8, 2001 LETS GET TO THE CHROMATOGRAPHY

30 CLP Pesticides B-0447 March 8, 2001 WHAT EXACTLY ARE WE TRYING TO ACHIEVE The best resolution possible Minimize analysis time Get MDLs as low as possible

31 CLP Pesticides B-0447 March 8, 2001 RESOLUTION VS SEPARATION Separation: Time between the 2 peaks Resolution: Describes how well 2 peaks are separated with regard to their widths

32 CLP Pesticides B-0447 March 8, (t m = 95.5) WHICH PAIR OF SOLUTES HAVE BETTER SEPARATION?

33 CLP Pesticides B-0447 March 8, Better Separation  = 1.17 R s = 0.6 Better Resolution  = 1.05 R s = 2.7 K = 7.00K = 6.07 K = 6.00K = 6.30 RESOLUTION VS SEPARATION

34 CLP Pesticides B-0447 March 8, 2001 RESOLUTION AND ANALYSIS TIME Improving resolution often results in the opportunity to shorten analysis times Many variables can affect resolution

35 CLP Pesticides B-0447 March 8, 2001 N=  (L, r c ) k =  (T, d f, r c )  =  (T, phase) R Nk k s = 41 1                 RESOLUTION

36 CLP Pesticides B-0447 March 8, 2001 The column must provide sufficient retention of the early eluting compounds without excessive retention of the late eluting compounds IMPROVING RESOLUTION Retention

37 CLP Pesticides B-0447 March 8, 2001 IMPROVING RESOLUTION Film Thickness Decreasing Film Thickness Results In: Increased efficiency Elution of analytes at lower temperatures Decreased analysis time Decreased bleed interference Increased column activity Decreased capacity

38 CLP Pesticides B-0447 March 8, 2001 IMPROVING RESOLUTION Efficiency High column efficiency is necessary to resolve large numbers of compounds Improperly operated injectors and/or improperly optimized carrier gas can result in efficiency losses

39 CLP Pesticides B-0447 March 8, 2001 IMPROVING RESOLUTION Column Length Increasing Column Length Results In: Increased efficiency Increased analysis time Increased bleed Big increase in cost

40 CLP Pesticides B-0447 March 8, 2001 IMPROVING RESOLUTION Column Inner Diameter Decreasing Column Inner Diameter Results In: Increased efficiency Increased head pressure Decreased capacity Decreased carrier gas flow rates

41 CLP Pesticides B-0447 March 8, 2001 IMPROVING RESOLUTION Stationary Phase Stationary phase selectivity has the largest impact on separation, thus resolution Optimization of stationary phase selectivity should be approached cautiously

42 CLP Pesticides B-0447 March 8, 2001 For Years Environmental Laboratories Have Suffered With Pesticide Analyses Using Non- Optimal Stationary Phases

43 CLP Pesticides B-0447 March 8, 2001 TRADITIONAL STATIONARY PHASES 5% Phenyl-methylpolysiloxane 35-50% Phenyl-methylpolysiloxane Trifluoropropyl-methylpolysiloxane 14% Cyanopropylphenyl-methylpolysiloxane

44 CLP Pesticides B-0447 March 8, 2001 PROBLEMS WITH TRADITIONAL PHASES Long analysis times (Over 30 minutes!) High bleed resulting in decreased sensitivity Poor resolution and confirmation capabilities Poor inertness of some phases

45 CLP Pesticides B-0447 March 8, 2001 TRADITIONAL PESTICIDE COLUMNS

46 CLP Pesticides B-0447 March 8, 2001 EFFORTS TO IMPROVE PESTICIDE ANALYSES Application Specific Phases Stationary phases designed with a primary focus placed upon maximizing separation (  ) for a specific group of target analytes

47 CLP Pesticides B-0447 March 8, 2001 APPLICATION SPECIFIC PHASES C 2 H 4 CF CH 3 m n Si O O 3 Phase 1 Trifluoropropyl-dimethylpolysiloxane 3 CH 3 m n Si O O C 2 H 4 CF CH 3 3 Common CLP Pesticide Phases Phase 2 Trifluoropropyl-diphenyl-dimethylpolysiloxane Dimethyl functionality of Phase 2 not shown

48 CLP Pesticides B-0447 March 8, 2001 EFFECT OF PHASE POLARITY Polarity Thermal Stability

49 CLP Pesticides B-0447 March 8, 2001 DRAWBACKS OF APPLICATION SPECIFIC PHASES Limited thermal stability resulting in longer analysis times and hampered sensitivity Excessive column conditioning times leading to increased column activity Decreased column lifetimes

50 CLP Pesticides B-0447 March 8, 2001 PHASES DESIGNED WITH OPTIMUM PERFORMANCE IN MIND Arylene Phase Technology

51 CLP Pesticides B-0447 March 8, 2001 CH Si O O O O Biphenyl CH Si O O Arylene LOW BLEED STATIONARY PHASES Arylene Structure

52 CLP Pesticides B-0447 March 8, 2001 DB-35ms DB °C 300°C CLP Pesticides Analysis LOW BLEED STATIONARY PHASES DB-35ms vs. DB-35

53 CLP Pesticides B-0447 March 8, 2001 STATIONARY PHASE AFFECT ON SENSITIVITY Both 30 m x 0.25 mm I.D., x 0.25 µm 5 ng Decachlorobiphenyl S/N =10S/N =3 DB-35ms, 320°CDB-35, 300°C

54 CLP Pesticides B-0447 March 8, 2001 LOW BLEED STATIONARY PHASES Spectral Purity

55 CLP Pesticides B-0447 March 8, 2001 BENEFITS OF LOW BLEED STATIONARY PHASES Improved sensitivity Improved spectral purity Reduced analysis times Potential increase in column lifetimes Rigorous inertness testing Less Detector maintenance

56 CLP Pesticides B-0447 March 8, 2001 Break Number 1 For Questions and Answers Press *1 on Your Phone to Ask a Question

57 CLP Pesticides B-0447 March 8, 2001 DEMANDING PESTICIDE APPLICATIONS BENEFIT FROM ADVANCED PHASE TECHNOLOGY DB-35ms and DB-XLB capillary columns contain second generation arylene stationary phases giving them enhanced thermal stability

58 CLP Pesticides B-0447 March 8, 2001 DB-35MS PRIMARY COLUMN CLP Pesticides Should provide adequate resolution of all 22 CLP Pesticides and surrogates Short analysis time ideal Easily realized analysis conditions preferable Should give minimal column bleed

59 CLP Pesticides B-0447 March 8, Tetrachloro-m-xylene (SS) 2.  -BHC 3.  -BHC 4.  -BHC 5.Heptachlor 6.  -BHC 7.Aldrin 8.Heptachlorepoxide 9.  -Chlordane 10.  -Chlordane 11.Endosulfan I 12.4,4’-DDE 13.Dieldrin 14.Endrin 15.4,4’-DDD 16.Endosulfan II 17. 4,4’-DDT 18. Endrinaldehyde 19.Endosulfan sulfate 20.Methoxychlor 21.Endrinketone 22.Decachlorobiphenyl (SS) CLP PESTICIDES Column: DB-35ms 30 m x 0.32 mm I.D., 0.25 µm P/N: Carrier: Helium at 45 cm/sec (EPC in constant flow mode) Oven: 110°C for 0.5 min °C at 15°C/min 320°C for 2 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow) Short Analysis Time Low Bleed At 320ºC

60 CLP Pesticides B-0447 March 8, 2001 DB-XLB CONFIRMATION COLUMN With Regard To The Primary Column Should resolve any co-elutions Needs to provide adequate resolving power when run under the same analytical conditions Should possess at least equivalent thermal stability Should provide a different relative elution pattern Ideally, elution order changes should be realized

61 CLP Pesticides B-0447 March 8, 2001 CLP PESTICIDES Column: DB-XLB 30 m x 0.32 mm I.D., 0.50 µm P/N: Carrier: Helium at 45 cm/sec (EPC in constant flow mode) Oven: 110°C for 0.5 min °C at 15°C/min 320°C for 2 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow) % Confirmation In Under 16 Minutes 1.Tetrachloro-m-xylene (SS) 2.  -BHC 3.  -BHC 4.  -BHC 5.Heptachlor 6.  -BHC 7.Aldrin 8.Heptachlorepoxide 9.  -Chlordane 10.  -Chlordane 11.Endosulfan I 12.4,4’-DDE 13.Dieldrin 14.Endrin 15.4,4’-DDD 16.Endosulfan II 17. 4,4’-DDT 18. Endrinaldehyde 19.Endosulfan sulfate 20.Methoxychlor 21.Endrinketone 22.Decachlorobiphenyl (SS)

62 CLP Pesticides B-0447 March 8, 2001 OPTIMIZING FOR SPEED WITHOUT SACRIFICING ANALYTE RESOLUTION Use Hydrogen as the carrier gas Set linear velocity at 65 cm/sec (3.4 mL/min) Increase oven ramp rate from 15°/min to 25°/min

63 CLP Pesticides B-0447 March 8, 2001 CLP PESTICIDES USING HYDROGEN CARRIER GAS Column: DB-35ms 30 m x 0.32 mm I.D., 0.25 µm P/N: Baseline Resolution In Under 9 Minutes! Carrier: Hydrogen at 65 cm/sec (EPC in constant flow mode) Oven: 110°C for 0.5 min °C at 25°C/min 320°C for 2 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow)

64 CLP Pesticides B-0447 March 8, 2001 Carrier: Hydrogen at 65 cm/sec (EPC in constant flow mode) Oven: 110°C for 0.5 min °C at 25°C/min 320°C for 2 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow) CLP PESTICIDES USING HYDROGEN CARRIER GAS Column: DB-XLB 30 m x 0.32 mm I.D., 0.5 µm P/N: Excellent Resolution And Confirmation In Under 10 Minutes

65 CLP Pesticides B-0447 March 8, 2001 OTHER COMMON ECD APPLICATIONS THAT THIS DUAL COLUMN SHOULD BE ABLE TO PERFORM EPA 8151A (Phenoxy acid herbicides) EPA (Pesticides) EPA (Haloacetic acids) EPA 8082 (PCB congeners and Aroclors)

66 CLP Pesticides B-0447 March 8, Time (min) EPA 8151A PHENOXY ACID HERBICIDES DB-XLB C Time (min) DB-35ms C

67 CLP Pesticides B-0447 March 8, 2001 EPA 8151A PHENOXY ACID HERBICIDES DB-35ms 30m x 0.32 mm I.D., 0.25 µm P/N: DB-XLB 30m x 0.32 mm I.D., 0.50 µm P/N: Carrier: Helium at 45 cm/sec (EPC in constant flow mode) Oven: 50°C for 0.5 min °C at 25°C/min °C at 12°C/min 320°C for 2 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow) 1. Dalapon 2. 3,5-Dichlorobenzoic acid 3. 4-Nitrophenol 4. Methyl-2,4-dichlorophenylacetate (SS) 5. Dicamba 6. MCPP 7. MCPA 8. 4,4´, Dibromooctafluorobiphenyl (IS) 9. Dichloroprop 10. 2,4-D 11. Pentachlorophenol 12. 2,4,5-T,P 13. 2,4,5-T 14. Chloramben 15. Dinoseb 16. 2,4-DB 17. Bentazone 18. DCPA 19. Picloram 20. Acifluorofen

68 CLP Pesticides B-0447 March 8, 2001 EPA PESTICIDES DB-XLB DB-35ms Time (min) Time (min) , , ,10 9, C787 C786

69 CLP Pesticides B-0447 March 8, 2001 EPA PESTICIDES DB-35ms 30m x 0.32 mm I.D., 0.25 µm P/N: DB-XLB 30m x 0.32 mm I.D., 0.50 µm P/N: Carrier: Helium at 45 cm/sec (EPC in constant flow mode) Oven: 75°C for 0.5 min °C at 10°C/min 300°C for 2 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow) 1. Hexachloropentadiene 2. Etridiazole 3. Chloroneb 4. Trifluralin 5. Propachlor 6. Hexachlorobenzene 7. a-BHC 8. Atrazine 9. Pentachloronitrobenzene (IS) 10. Simazine 11. g-BHC 12. b-BHC 13. Hepatachlor 14. Alachlor 15. d-BHC 16. Chlorothalonil 17. Aldrin 18. Metribuzin 19. Metolachlor 20. DCPA 21. 4,4´-Dibromobiphenyl (SS) 22. Heptachlor epoxide 23. Cyanazine 24. g-Chlordane 25. a-Chlordane 26. Endosulfan I 27. 4,4´-DDE 28. Dieldrin 29. Chlorobenzilate 30. Endrin 31. 4,4´-DDD 32. Endosulfan II 33. 4,4´-DDT 34. Endrin Aldehyde 35. Endosulfan sulfate 36. Methoxychlor 37. cis-Permethrin 38. Trans-Permethrin

70 CLP Pesticides B-0447 March 8, 2001 EPA HALOACETIC ACIDS DB-XLB DB-35ms Time (min) , Time (min) 1 4 2, C789 C788

71 CLP Pesticides B-0447 March 8, 2001 EPA HALOACETIC ACIDS 1. Chloroacetic acid 2. Bromoacetic acid 3. Dichloroacetic acid 4. Dalapon 5. Trichloroacetic acid 6. 1,2,3-Trichloropropane (IS) 7. Bromochloroacetic acid 8. Bromodichloroacetic acid 9. Dibromoacetic acid 10. 2,3-Dibromopropionic acid (SS) 11. Chlorodibromoacetic acid 12. Tribromoacetic acid DB-35ms 30m x 0.32 mm I.D., 0.25 µm P/N: DB-XLB 30m x 0.32 mm I.D., 0.50 µm P/N: Carrier: Helium at 45 cm/sec (EPC in constant flow mode) Oven: 40°C for 0.5 min °C at 15°C/min 200°C for 2 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow )

72 CLP Pesticides B-0447 March 8, 2001 EPA 8082 PCB CONGENERS DB-XLB DB-35ms Time (min) Time (min) C791 C790

73 CLP Pesticides B-0447 March 8, 2001 EPA 8082 PCB CONGENERS 1. IUPAC 1 2. Tetrachloro-m-xylene (IS/SS) 3. IUPAC 5 4. IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC IUPAC Decachlorobiphenyl (IS/SS) DB-35ms 30m x 0.32 mm I.D., 0.25 µm P/N: DB-XLB 30m x 0.32 mm I.D., 0.50 µm P/N: Carrier: Helium at 45 cm/sec (EPC in constant flow mode) Oven: 110°C for 0.5 min °C at 15°C/min 320°C for 5 min Injector: Splitless, 250°C 30 sec purge activation time 50 pg per component Detector: µECD, 350°C Nitrogen makeup gas (column + makeup flow = 30 mL/min constant flow )

74 CLP Pesticides B-0447 March 8, 2001 WHAT DOES THIS MEAN FOR ENVIRONMENTAL LABORATORIES? Improved productivity Increased sample throughput Superior results Total solution for ECD systems

75 CLP Pesticides B-0447 March 8, 2001 CONCLUSION Excellent selectivity Exceptional inertness Superb thermal stability DB-35ms and DB-XLB provide excellent resolution and confirmation for CLP Pesticides and other critical GC/ECD methods providing total performance:

76 CLP Pesticides B-0447 March 8, 2001 CONCLUSION When optimized columns are combined with effective injector setup and detector design improved testing results are realized while sample throughput and laboratory efficiency are improved dramatically

77 CLP Pesticides B-0447 March 8, 2001 AGILENT’S J&W TECHNICAL SUPPORT It’s Free! (800) (phone) (916) (phone) (916) (FAX) web site:

78 CLP Pesticides B-0447 March 8, 2001 Wrap-up E-Seminar Questions Thank you for attending Agilent e-Seminars. Our e-Seminar schedule is expanding, please check our website frequently at:


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