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Elemental, My Dear Watson

Paul Middlestead University of Ottawa, G.G. Hatch Laboratory For 19th Continuous Flow Conference, Calgary, 2013. Elemental, My Dear Watson. This talk is for new users We will touch the basics on Elemental analysers A mix bag of tricks and advices Refer to manufacturer’s instruction manuals

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Elemental, My Dear Watson

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  1. Paul Middlestead University of Ottawa, G.G. Hatch Laboratory For 19th Continuous Flow Conference, Calgary, 2013 Elemental, My Dear Watson

  2. This talk is for new users • We will touch the basics on Elemental analysers • A mix bag of tricks and advices • Refer to manufacturer’s instruction manuals • Only endorsed products are: Rickards Red and Rickards White Who/whatisthis talk for?

  3. EA TC/EA Combustion Pyrolysis NCHS HO Large capacity S only TOC Stable isotopes Meetmyfamily 12000C 15000C

  4. Leco is the most popular manufacturer of elemental analysers. Every department has one or two of those accumulating dust. • Static combustion using oxygen: not suitable for IRMS Meet Grand Pa

  5. Let’s touch on • Elemental Analyser as an…instrument • Schematics • Autosamplers • Flash combustion • Chemicals & Configurations • Gas Chromatography • Thermal Conductivity Detector • Typical run • Common problems • EA-IRMS

  6. Simultaneous determination of Nitrogen, Carbon, Hydrogen, Sulfur, Oxygen • Measuring range: 100 ppm to 100% • Sample size: 0.1 to 1000 mg / 0.1 to 25 ul • Detection limit: 10 ppm • Accuracy: 0.3% - 0.02% absolute EA as an …. instrument

  7. CE instruments (Carlo Erba) models 1108, 1110, NA 1500, NA 2100, Flash 1112 • Costech Model ECS4010 • Elementar cube family • Eurovector models EuroEa3028-HT, Ea3024-IRMS, pyrolysis model • Sercon-Integra • TC\EA Thermo • … Manufacturers, models blablabla

  8. Organic compounds • Pharmaceuticals • Organometallics • Petrochemicals • Gasoline & fuels • Graphite • Carbides & nitrides • Metals & alloys • Polymers • Explosives • Hydrocarbons • Soils • Coal & coke • Liquids EA : Bulk analysis of NCHS/O In short, you can combust your grandmother!

  9. Typical EA setup with IRMS Ref gas 1 He Ref gas 2 2 m Elemental Analyser (CNS) (OH) Isotope Ratio Mass Spectrometer Interface

  10. EA picture

  11. Autosampler He O2 Gas chromatography Column in oven Thermal Conduc- tivity Detector Water Trap EA line out TCD Elemental Analyser Schematic CO2 N2 Reduction Chemicals 650C Combustion Chemicals 1020C H2O SO2

  12. Found the problem with the previous slide?A beer if you do…(5 seconds)

  13. Autosampler He O2 Gas chromatography Column in oven Thermocouple Detector Water Trap EA line out TCD Elemental Analyser Schematic CO2 N2 Reduction Chemicals 700C Combustion Chemicals 1020C H2O SO2

  14. A cold Rickard’sRedfor me please.

  15. Sample/Std is weighed and wrapped in tin foil, placed in culture tray/autosampler • Sample drops is flash-combusted in O2 in He stream, causing rapid cracking and oxidation of gases stoichiometrically equivalent to their elemental components, some gas oxides need to be reduced before obtaining final products (N2, CO2, H2O, SO2) i.e. oxidation and reducing reactions involved Typical Analysis Procedure for EA

  16. Separation of gases by gas chromatography or chemical column traps • Detection by thermal conductivity detector (TCD) or IRMS. • Curve made from weighing certified stds (for isotope and/or quantitative measurements) Typical Analysis Procedure for EA

  17. Some torture tools…

  18. Wellwell, got culture?

  19. Supersizeme

  20. MAIS C’EST IMPOSSIBLE!

  21. Filters? Careful! C’EST FANTASTIQUE!

  22. Not flat please

  23. Autosamplers (AS128)

  24. Autosamplers (AS200)

  25. Zero Blank

  26. Zero Blank modified

  27. Special tools required ECS 4010

  28. Take 20 minutes to study the gasschematics of your instrument Be good to yourself

  29. TO AUTOSAMPLER He only He 99.996 O2 99.998 Loop concept (a) SAMPLE LOOP 10 , 5 , 3 ML OXYGEN OUT

  30. TO AUTOSAMPLER He + O2 + He He O2 Loop concept (b) SAMPLE LOOP 10 , 5 , 3 ML OXYGEN OUT

  31. Combustion starts Flash should occur within 2-3 seconds of being dropped Injected O2 Sample drops START Sample dropping 10 20 30 40 0 seconds

  32. PLATINUM: Absorbs much of the heat of the reactor before passing it on to the sample, slowing down reaction • ALUMINIUM: Supplies good oxidation flash and prime sample ignition but does not melt or mix with the sample thus does not promote inner oxidation • SILVER: Melts at 9600C, does not take part in the combustion, retains trace of carbon when in molten state • TIN: Inexpensive & takes active part in process. Melts at 2350C with very low enthalpy, intermixes with organic and inorganic substances, expedites the final oxidation reaction Why you Tin man?

  33. Increases local temperature from 10200C to 1700-18000C, accelerating combustion • Cancels the endothermic effects of tin melting (0.14 calories required for melting vs 11.96 calories given off during flash) • Equalizes the thermal degradation of any substance • Uses available oxygen immediately and requires less Sn + O2 SnO2+ 142 000 cal 2350C 1700-1800C Dynamic Flash CombustionOxidation of TIN gives a tremendous enthalpy reaction

  34. Ensures that sample oxidation is performed in gaseous phase (95%) rather than in the catalytic reactions • Breaks down any matrix without combustion aid • Converts the sample into a homogenous, quantitative combustion gas mixture (unfractionated) • Provides a gaseous plug for the entry into the GC column • Forms tin oxide, an oxidation catalyst • Provides visual indication of the reaction Dynamic Flash CombustionOxidation of TIN gives a tremendous enthalpy reaction

  35. C CO2 CO2 Reduction tube Combustion tube N N2 + NxOx N2 HH2O H2O Let’s get cracking S SO2 + SO3 SO2

  36. System should be optimized for element(s) to be analyzed • One-tube system: both oxidant catalyst and reducing chemicals in one tube; usually used if S is to be analyzed • Two-tube system: one tube for oxidant, one tube for reducing chemicals; usually used for N, NC or NCH • Chemical traps: Mg Perchlorate or Anhydrone will trap H2O, and Carbosorb will trap CO2 (and SO2) Chemicals and Configurations

  37. ConfigurationCN

  38. ConfigurationS

  39. Small isbeautiful

  40. Usinggrindingtools and dilutedNitricacid, one canre-use combustion and reduction tubes More torture tools

  41. Gas chromatographic columns will separate different components according to their polarity and molecular size. • Factors influencing the quality of the chromatography: column length, size of packing, tube diameter, stationary phase type, flow rate, temperature. • Packed column: packed polymer beads, different sizes available. High capacity , low resolution. • Capillary column: small capillary with polymeric film on inner wall. High resolution, low capacity. • Deactivated fused silica is free of adsorption problems encountered with most packings or capillaries columns. Gas Chromatography

  42. He + N2 , CO2 , H2O , SO2 + He He + SO2 + H2O+ CO2 + N2 + He INCREASING POLARITY OF GASES Gas Separation/ GC

  43. He + SO2 + H2O+ CO2 + N2 + He DETECTOR CO2 N2 SO2 H20 DETECTOR What after we separate? TIME

  44. TCD SO2 CO2 H2O Gas Separation / Purge & Trap

  45. Thermal conductivity detector (TCD) Heated filament from which heat is removed at a constant rate by He gas stream. Change in heat transfer is caused by presence of analyte molecules with different thermal conductivities than He. Relatively low sensitivity, excellent range and linearity. Non-destructive. Electron capture detector (ECD) Electrons are captured by organic species in ionized carrier; used for trace sulfur determination. Isotope Ratio Mass Spectrometer (IRMS) Detectors

  46. TCD schematic

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