Headspace Technology for GC and GC/MS: Features, benefits & applications Karima Baudin Oct 2015
Why use Headspace? Very Simple no to minimum sample prep Robust enhance uptime Non-detectable carry-over Inert sample path Enhance accuracy and repeatability Excellent repeatability Investigating volatiles in many matrices Avoid extraction Eliminate losses Prevent non-volatiles from entering chromatographic system Enables aggressive detection limits Concentrator 1mL, 2mL entire volume. enhance productivity and efficiency - saves time and money
BLOOD FILMS Enables the Analysis of Volatiles In Matrices Which Cannot Be Directly Injected BEER RESINS GELS DETERGENTS
Advantages of using HeadSpace technology Maintenance: is there any? No Septum to change No Liner to change No Glass Wool required (no active sites) No Syringe to clean
Advantages of using HeadSpace technology Saves Time Not changing the above (or forgetting to change them) Analysis time - Shorter runs analyzing Volatiles not Matrix
Advantages of using HeadSpace technology Saves Money Increase productivity Minimal consumables Extends Column Live
Three sampling methods Static (equilibrium) Headspace Multiple Headspace Extraction (MHE) Total Evaporation
Static or Equilibrium Headspace
Partition equilibrium of analyte i between liquid and gas phase Consider: Time Temperature Solute i Liquid Sample
Balanced Pressure Sampling Standby Pressurization Sampling
How Sampling works HS Trap
Why use Headspace Trap (HS Trap) instead of conventional HS Enhance Detection Limits by at least 50 Enables injection of entire HS vapor plus more with multiple injections of same vial focusing on a trap Dry Purge remove water excellent water management Removes Oxygen Enables the use of Narrow Bore Short columns for Fast GC
Sample Vial Thermal Equilibration detector valve trap seal column vial oven Headspace Sampler Gas Chromatograph
Vial Pressurization detector valve trap seal column vial oven Headspace Sampler Gas Chromatograph
Trap Load column isolation valve trap seal detector column vial oven Headspace Sampler Gas Chromatograph
Vial Re-Pressurization detector valve trap seal column vial oven Headspace Sampler Gas Chromatograph
Trap Re-Load detector valve trap seal column vial oven Headspace Sampler Gas Chromatograph
Dry Purge detector valve trap seal column vial oven Headspace Sampler Gas Chromatograph
Trap Desorption detector valve trap seal column vial Trap desorbed in Opposite direction oven Headspace Sampler Gas Chromatograph
Applications
New USP Residual Solvent Test by Static Headspace Technique Class 1 Residual Solvents Class 2 - Mixture B Residual Solvents Class 3 Residual Solvents (continued) 1,2-Dichloroethane 1,1,1-Trichloroethane Carbon Tetrachloride Benzene 1,1-Dichloroethene Chloroform 1,2-Dimethyoxyethane Hexane Methylbutylketone Nitromethane Pyridine Tetralin Trichloroethylene Heptane Isobutyl Acetate Isopropyl Acetate Methyl Acetate 3-Methyl-1-Butanol Methylethylketone Methylisobutylketone 2-Methyl-1-propanol Pentane 1-Pentanol 1-Propanol 2-Propanol Class 2 - Mixture A Residual Solvents Acetonitrile Chlorobenzene Cyclohexane c-1,2-dichloroethene t-1,2-dichloroethene Methylene Chloride 1,4-Dioxane Methanol Methylcyclohexane Tetrahydrofuran (THF) Toluene Ethyl Benzene m-xylene p-xylene o-xylene Class 3 Residual Solvents Acetic Acid Acetone Anisole 1-Butanol 2-Butanol Butyl Acetate t-butylmethyl ether Cumene Dimethyl sulfoxide Ethanol Ethyl Acetate Ethyl Ether
Blank (bottom) / Class 1 Standard Solution (top) 1 4 2 5 3 Standard Solution Blank 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 HS Conditions 10.5 11.0 11.5 Eq. Temp: 80oC Eq. Time: 15min Inj Volume: 1mL Needle Temp: 110oC T Line Temp: 130oC Injector Temp: 140oC
Class 1: Comparing results on 0.32 id column to 0.53 id column - 10.05-9.68-8.92-8.57-3.87 All method criteria are achieved PE Elite 624 30m x 0.32mm x 1.8um 7.8 7.6 13.0 7.4 12.5 12.0 7.2 1 11.5 7.0 4 2 Component PPB Area S/N 1,1-Dichloroethene 1,1,1-Trichloroethane Carbon Tetrachloride Benzene 1,2-Dichloroethane 64.7 83.3 33.0 17.0 42.2 14685 14097 2185 14116 7546 34 : 1 35 : 1 6:1 35 : 1 17 : 1 11.0 1 2 3 4 5 6.8 10.5 6.6 10.0 6.4 5 9.5 6.2 9.0 8.5 6.0 8.0 5.8 3 7.5 5.6 7.0 5.4 6.5 0.5 6.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.0 10.5 10.5 11.0 11.5 5.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 11.0 11.5 12.0 12.5 PE Elite 1301 30m x 0.53mm x 3.0um 1 Component PPB Area S/N 1,1-Dichloroethene 1,1,1-Trichloroethane Carbon Tetrachloride Benzene 1,2-Dichloroethane 64.7 83.3 33.0 17.0 42.2 38361 36551 4658 36528 14349 143 : 1 86 : 1 11 : 1 89 : 1 36 : 1 4 2 5 3 1 2 3 4 5
- 10.05-9.68-8.92-8.57-3.87 Headspace vs Headspace Trap Residual Solvents Class 1 Conventional Headspace 7.8 7.6 7.4 4 7.2 1 7.0 2 6.8 Component PPB Area S/N 1,1-Dichloroethene 1,1,1-Trichloroethane Carbon Tetrachloride Benzene 1,2-Dichloroethane 64.7 83.3 33.0 17.0 42.2 14685 14097 2185 14116 7546 34 : 1 35 : 1 6:1 35 : 1 17 : 1 6.6 1 2 3 4 5 5 6.4 6.2 6.0 5.8 3 5.6 5.4 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 Residual Solvents Class 1 Headspace Trap - 10.13 7.0-9.75 6.5-9.00 6.0-8.66 5.5-5.07 5.0-4.86 4.5-4.41-4.20 4.0-4.00 3.5-3.63 3.0-3.01 2.5-2.74 2.0-2.39 1.5-2.00 1.0-0.58 0.5 50 45 40 35 30 1 2 3 4 5 25 20 15 10 5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 Component PPB Area S/N 1,1-Dichloroethene 1,1,1-Trichloroethane Carbon Tetrachloride Benzene 1,2-Dichloroethane 64.7 83.3 33.0 17.0 42.2 123689 230364 38202 184737 81162 1021: 1 969 : 1 156 : 1 816 : 1 377 : 1
Analytical Performance of BTEX acquiring in Full Scan s/n at 0.02 ppb 100 Benzene Toluene Ethyl Benzene m,p-xylenes* o-xylene Linearity, r2 Precision at 1 ppb 0.02 to 60 ppb (n=7) 370 to 1 550 to 1 578 to 1 670 to 1 240 to 1 0.9996 0.9994 0.9993 0.9997 0.9994 3.65 2.85% 2.76% 2.53% 1.07% 3.86% O-Xylene 3.61 3.06 3.81 % 2.44 Chromatogram is 4 ppb 0 Time 1.55 1.65 1.75 1.85 1.95 2.05 2.15 2.25 2.35 2.45 2.55 2.65 2.75 2.85 2.95 3.05 3.15 3.25 3.35 3.45 3.55 3.65 3.75 3.85 3.95 Under four minutes
Amount of Ethanol in Glycerin Soap via Headspace GC This test was performed via equilibrium HS and total evaporation techniques. Equlibrium Headspace Sample Received same results with both techniques 3% ethanol in soap 3% is a lot of material so dilution and/or using total evaporation works well Since total evaporation is easier, this would be the recommended technique (both are described) Soap is a matrix that cannot be directly injected into a GC inlet and extraction is laborious. Headspace provided a quick, precise, accurate means of determining the amount of ethanol in soap while significantly reducing labor time and costs. Weigh 0.20g of soap into vial Fill vial with 5mL of water Cap vial and place on autosampler Standard Prepare a standard of known concentrations in water Add 5mL aliquot of this standard to HS vial Cap vial and place on autosampler and run Software calculates results (Std amt and sample weight is entered into appropriate places in software) For single level calibration (response unknown/response std)*std conc.=amount of unknown Total Evaporation Sample Weigh 0.2g of soap into vial Cap vial and place on autosampler Thermostat sample at temp that will volatilize ethanol from matrix leaving most matrix in vial Standard ETHANOL Prepare a known standard in a volatile solvent Add 20uL into HS vial. The amount of ethanol into vial is known Software calculates results
Analytes in Paper - Headspace - GC / MS (5g paper) good_sample_2 Scan EI+ TIC 1.40e7 Sample Temp: 150oC 100 Th Time: 30 min good_sample_2 2369 (34.090) Cm (2369-2406:2418) 41 100 % % 43 54 38 70 57 29 39 67 66 83 81 72 84 98 110 111 121 136 0 40 Scan EI+ 1.97e5 55 60 80 100 120 140 153154163 160 186 180 202 200 265 220 240 260 325 280 300 320 340 360 380 400 2-decenal 2 Time 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00
Determination of amount of Fragrance in a polymer sphere by Headspace Sample Matrix: Fragrance is suspended in a polymeric sphere. The amount of fragrance in this matrix needs to be known for QC purposes. Injecting polymer directly into GC, would have resulted in time consuming maintenance. Extracting fragrance, would have been time consuming and expensive. In addition, the extraction recoveries could be poor and also selective depending upon analyte. With Headspace: Easy, fast sample prep. Extremely low maintenance Precise, accurate results Sample Preparation: 0.06 g sample in 1mL THF Volume in HS vial: vial 20 ul aliquot in HS vial cap Standard Preparation: Prepare fragrance at known concentration in THF Volume of Std in vial: 20uL of standard in HS vial cap vial Sample Temp: 120oC (this temperature was enough to completely volatilize the fragrance but not the matrix Required detection limits and accurate results were attained. The fragrance amount calculated at 15% which was the expected amount Using HS resulted in reduced costs and time Chromatogram of fragrance in a matrix by HS/GC
Analyzing Beer
Characterizing Flavors in Beer and starting products: HSTrap/GC/MS Sample Size: Beer Flavors HS_GC_MS Excellent Chromatography Required detection limits Repeatable response Linear response 100 Sample Temp: 16.59;70 5 ml Scan EI+ oc 70TIC 2.95e10 Sample Load: 1 cycle Trap Load Temp: 25oC Dry Purge: 6 min Trap high Temp: 300oC Needle Temp: 160oC T Line Temp: 180oC Column Flow: 22.31 70 16.76 55 Pressure Pulse: 2mL/min for 0.4min Analytical Flow Rate 1mL/min % 6.04 46 11.43 12.02 43 61 30.33 88 Propyl acetate 10.15 43 26.01 88 22.42 43 18.17 19.26 43 43 31.54 104 33.77 88 0 Time 6.50 8.50 10.50 12.50 14.50 16.50 18.50 20.50 22.50 24.50 26.50 28.50 30.50 32.50 34.50
Blood Alcohol composite Oven Temp: 70 oc Needle Temp: 110 oc T Line Temp: 120 oc HS psi: 25 psi Column psi: 21 psi Column Flow: 3 ml/min dual channel Columns: BAC 1-30m x 0.32mm x 1.8um BAC 2-30m x 0.32mm x 1.2um n-propanol IPA Acetone Ethanol 40oC isothermal Methanol GC Oven Temp:
Flavors in Green Tea HS/GC/MS Green Tea_HS_05 Scan EI+ TIC 2.58e8 100 Sample Size: Sample Temp: Needle Temp: T Line Temp: Column Flow: 1.6488 g 130oC 180oC 180oC 4 ml/min for 0.2 min then 1mL/min 35 to 400 amu 7.83 96 Mass Range: % 7.92 96 24.24 59 3.22 45 19.32 93 2.78 46 5.35 45 14.58 93 17.88 93 16.22 119 18.97 95 19.81 93 17.10 91 22.50 112 23.37 95 6 Time 2.88 4.88 6.88 8.88 10.88 12.88 14.88 16.88 18.88 20.88 22.88 24.88 26.88
I-Octane Methyl Sterate o-xylene P&M Xylene Volatiles and Semi-Volatiles in High Density Polyethylene
Off odors in Resin 3.2g in vial HS/GC/MS 032700_008 Scan EI+ TIC 7.10e6 100 Mal-odor investigation 19.65 43 % 9.41 45 8.22 45 31.05 57 6.61 56 11.88 42 5.93 44 4.03 44 32.93 34.01 57 57 12.49 45 32.09 57 9.85 43 27.30 28.14 71 57 7.06 44 17.81 18.44 46 55 34.97 57 26.47 57 22.19 55 7 Time 5.40 7.40 9.40 11.40 13.40 15.40 17.40 19.40 21.40 23.40 25.40 27.40 29.40 31.40 33.40 35.40 37.40
Off odors in Resin 0.5g in vial HS/GC/MS 041300_001 Scan EI+ TIC 4.74e7 35.37 101 100 39.50 96 45.69 67 40.52 43 % 10.78 43 45.51 95 27.80 73 38.15 58 7.76 58 46.74 67 42.62 55 10.31 45 43.28 58 31.81 73 12.11 43 15.51 55 33.57 44 44.11 96 37.92 119 21.45 45 53.84 58 0 Time 10.76 15.76 20.76 25.76 30.76 35.76 40.76 45.76 50.76
Summary the optimum technique for analyzing residual solvents Robust and stable Inert Excellent analytical results Precision Accuracy Detection Limits Minimal Maintenance User friendly interface Non-detectable carry-over Simple sample prep Enhance long term productivity and efficiency Enhance detection limits and repeatability with the HS Trap
Headspace Technology for GC and GC/MS: Features, benefits & applications Karima Baudin Oct 2015