Fausto Munari e Andrea Cadoppi ThermoFisher - Italy

Transcription

1 The world leader in serving science Ultra Fast GC Determination of Total Hydrocarbons (C7-C40) and BTEX in Water and Soils through Direct Resistively Heated capillary columns and Robotic Autosampler. Fausto Munari e Andrea Cadoppi ThermoFisher - Italy

2 Summary Official regulations for Total Hydrocarbons: GC as replacement of IR Ultra Fast GC and Triplus Autosampler ISO with Ultra Fast GC ISO (Mod.) with Ultra Fast GC 2

3 IR and GC methods Infra Red GC Method: EPA ISO TNRCC 1005 EPA 8015 ISO/TR ISO/TR (for Oil in soil and sediments) Extraction Solvent: CCl 4, Freon n-pentane, (banned) n-hexane TTCE Analysis Time: around 2 min 20 min 2 min by Ultra Fast GC 3

4 How fast is UFGC? UFGC (direct resistive heating) Rate ( C/min) Rate ( C/s) Conventional fast oven Final oven temperature ( C) 4

5 Ultra Fast GC: Requirements Ultra Fast heating capability ( C/min) Short capillary columns (typically 2-5m narrow-bore; or 0.32mm i.d. when separation power is not an issue) High pressure pneumatic control capability Fast Detector (High Frequency Response) 5

6 Direct column heating technology The heating element and the T sensor are wrapped around the column The column is mounted in a cage ULTRA FAST Column Module Dedicated heated interfaces for injector and detector NO oven heating is required Heater Capillary column Column assembly Ceramic fiber Temperature sensor The column module includes both heating and temperature sensing elements 6

7 The column module in the oven Column modules are housed in the GC oven and connected to inlet (SSL or PTV) and detector as a conventional capillary column Configurations used for TPH analysis: Additional heated block FID Injector SSL / FID PTV / FID Trace GC Ultra oven 7

8 Trace GC Ultra Column Module FEATURES Assemblies of 2, 5, 10 m ( mm i.d.) Up to 20 C/s (1200 C/min) temperature programming rates Broad temperature range (from 35 to 370 C) Cooling from 350 C to 50 C in about 1 min If needed, also cryo cooling is available (0 C minimum temp) Significant implications over conventional GC Faster analysis times Higher column lifetime Higher sensitivity: capability to handle trace analysis 8

9 Increased sensitivity - Peak compression effect 1.6E E E+05 nc20 (about 1ng) area (uv.s) 300 C/min 0.1 mm id column PW 1/2 = 0.10 s FID signal (uv) 1.0E E E E E C/min 0.32 mm id column PW 1/2 = 1.6 s Narrower peaks result in better signal to noise ratio 0.0E time (s) 9

10 E7 E8 E20 E9 E17 E18 E19 E10 E16 E15 E11 E12 E13 E14 E7 E8 E20 E19 E9 E18 E17 E10 E16 E15 E11 E14 E12 E13 Ultra Fast Analysis of FAME Classical Analysis 30 m, 0.32 mm id, 0.25 um Column TR-5 10 C/min 20 min 1 min Ultra Fast GC Analysis 5m, 0.10 mm id, 0.10 um Column TR C/min 1min 10

11 Retention Time repeatability study 10 C/s Carrier gas mode: constant flow (1 ml/min H2) Column 5m x 0.1 mm id, 0.1 um TR-5 70 to 330 C Split 1:200 Components 35 s 5 C/s 5 C/s nc10 nc12 nc nc20 nc22 nc23 4 nc16 9 nc25 60 s 5 5 nc C/s 2 C/s 110 s Time (s) 11

12 Retention Time repeatability Clear Identification: SD << peak width Rate ( C/s) Component Retention times Mean (s) SD (s) Peak widths at ½ h at 5% h 6 SD window* C C12 C C C C12 C C C C12 C C * In a ± 3 SD span there is a probability of 99.7 % for a measure to fall in 12

13 ISO ISO Norm Extraction of 900ml of water with 50 ml of n-hexane 2. Purification of the extract through Florisil, to remove interferences 3. Concentration of the extract from 50 to 1ml 4. GC analysis (FID detector) Solvent: n-hexane Range of hydrocarbons: C10-C40 13

14 Hydrocarbon analysis in water and soils Soil extract (50 mg/l tot. hydroc.) C10 C40 Splitless injection Total hydrocarbons 2 min time (min) Column :TR- 5m, 0.32 mm id, 0.25 um FT, T prog.: 40 (20s), 3.3 C/s, 350 (30s), Sample: Soil extract (50 ng/ul tot hyd.), Injection: 1 ul SPLITLESS, Splitless time: 20 s, Carrier: He at 5 ml/min CF 14

15 Hydrocarbon analysis in water and soils High linearity from 5 to 500 mg/l C40/C20 area ratio > 0.9 (required 0.8) RSD% on group peak absolute area 0.8% Area counts (*10^6) Calibration curve mg/l R Concentration (mg/l) 15

16 ISO SSL - UFM - Fast FID Trace GC Ultra Compliance with the requirements of the official methods Sampling Run Time Cooling Time 5 min High sample/day throughput! 100 samples in about 8h (a work-day)! 16

17 ISO QC sample (50 ng/µl) Column: 5 m x 0.32 mm id, 0.25 µm TR-5 Temperature Program: 40 C (0.3 ), 200 C/min to 350 C (0.5 ) Injection volume: 1 µl - splitless (mvolt) C10 Ultra Fast GC C Gain in speed Faster run Faster cooling Gain in sensitivity Peaks compression: peaks are narrower and consequently higher (mvolt) (sec) C Conventional GC (sec) 2 min C40 20 min 17

18 No more extract re-concentration! Ultra Fast GC LIQUID EXTRACTION SAMPLE CLEAN-UP SOLVENT EVAPORATIVE CONCENTRATION Conventional GC The sample reconcentration step can be by-passed! 18

19 ISO (Mod.) 2003: OSPAR proposed a new reference method ISO (Mod.), to get in force from January 2007 in North Sea area Solvent: n-pentane Range: C7-C40 BTEX havetobeseparatedaswell! Is it still possible to fulfil these specs at high speed of analysis? YES! using PTV Injector and Triplus Autosampler 19

20 Optimized PTV Injector Split Programmable Temperature Vaporizer (PTV) Cool Injection Prevents in-needle Discrimination During Transfer from the Needle to the Injector Higher Boiling Point Compounds Operate PTV independently of Column at Optimum Cool Temperature for Injection Sample evaporation zone Cold Permanently Heated Block at Base Avoids Cold Spots for the Sample Transfer to the Column Sample transfer line Hot 20

21 TriPlus Trio: AS, HS, and SPME Flexible Sampling Solutions Standard and Advanced Liquid sampling: From nano-volumes to Large Volume techniques (up to 450 µl) Accurate Headspace sampling: Zero bench space system based on gas tight syringe approach SPME (*) technique: Unprecedented fiber handling robustness to cut sample prep costs (*) under license from Supelco 21

22 TriPlus Technical Overview Main Features TriPlus AS TriPlus HS - Designed to fully exploit the potentiality of the GC Injectors - AS-HS convertibility; - Easy installation; - Multiple GCs configurations; Control software 22

23 Optimization of Injection : UFGC with Triplus Autosampler Robotic autosampler Optimum injection to avoid sample introduction discrimination over wider bp range Improved precision Cooling of syringe before sampling Avoid losses of light solvents Needle solvent Wash technique Depth of injection control Injection speed control 23

24 Ultra Fast GC : PTV Split injection of BTEX in n-pentane Column 5m x 0.1 mm id, 0.1 um TR TRACE GC-Channel 1 Fluorobenzene + BTEX Mix_New_40C Col temp Fluorobenzene + BTEX Mix_New_40C Col temp Name Retention Time If the analysis is performed at 40 C Initial Col Temp a loss of resolution is obtained! Millivolts Benzene Fluorobenzene Toluene Ethylbenzene m/p-xylene O-Xylene Millivolts Seconds 24

25 Co-solvent addition during injection What is a co-solvent? A liquid with: a lower volatility a different polarity (in some cases) Co-solvent addition: to tune solvent trapping effect to better managing difficult solvents and difficult solutes to reduce the total amount of solvent transferred to column and detector It is a momentary retention power that disappear by evaporation! 25

26 TriPlus: Software utilities Needle Solvent wash: selection of solvent vial position and solvent vial depth 26

27 Co-solvent addition trough the Autosampler syringe during PTVLVI injection at two different liner level Co-solvent Sample 27

28 Variation of injection speed and injection level during LVI Liner/precolumn conditions are different at the beginning and during injection Injection speed can be high at the beginning of the injection and reduced for the rest of the injection 28

29 PTV-BKF with Co-solvent addition during sampling PAH s in n-hexane with iso-octane ul in Hexane only ul Hexane +15ul Iso-octane

30 ON-Column LVI with co-solvent addition during injection 30

31 Ultra Fast GC : PTV Split injection of BTEX in n-pentane Column 5m x 0.1 mm id, 0.1 um TR TRACE GC-Channel 1 Fluorobenzene + BTEX Mix_New_40C Col temp Fluorobenzene + BTEX Mix_New_40C Col temp Name Retention Time If the analysis is performed at 40 C Initial Col Temp a loss of resolution is obtained! Millivolts Benzene Fluorobenzene Toluene Ethylbenzene m/p-xylene O-Xylene Millivolts Seconds 31

32 Injection and separation of BTEX (10ng/ul) + Fluorobenzene (20ng/ul) in Pentane using the cryo option for the oven Column 5m x 0.1 mm id, 0.1 um TR TRACE GC-Channel 1 Fluorobenzene + BTEX Mix_New 002_Fluorobenzene and BTEX Mix_New Name Fluorobenzene 5 C Initial Column Temp m/p_xylene Millivolts Benzene Toluene Ethylbenzene Millivolts 7000 O-Xylene Seconds 32

33 Co-Solvent addition applied during PTV injection Perfect solvent effect for BTEX at 40 C Column 5m x 0.1 mm id, 0.1 um TR TRACE GC-Channel 1 Fluorobenzene + BTEX Mix_New_40C Col temp_2ul with 1 MTBE Fluorobenzene + BTEX Mix_New_40C Col temp_2ul with 1 MTBE Name ul of MTBE added to 2 ul of Standard solution in n-pentane m/p_xylene C Initial Column Temperature! Millivolts Benzene Fluorobenzene Toluene Ethylbenzene O-Xylene Millivolts Seconds 33

34 Standard Mix BTEX and Hydrocarbons Column: 5 m x 0.1 mm id, 0.1 µm TR-5 Temperature Program: 38 C (0.8 ), 100 C/min to 350 C (0.5 ) Injection volume: 3µl split flow 20ml/min C40/C20 > 0.9 < 5 min 34

35 BTEX and Hydrocarbons separation 35

36 Mix Real Sample and BTEX in Pentane PTV injection with Co-solvent (MTBE) Millivolts Millivolts Name TRACE GC-Channel 1 2ul Real Sample in Pentane plus 1ul of MTBE 002_2ul Real Sample in Pentane plus 1ul of MTBE Minutes Seconds Benzene Fluorobenzene Toluene Ethylbenzene m/p_xylene O-Xylene Millivolts Millivolts Column 5m x 0.1 mm id, 0.1 um TR-5 TRACE GC-Channel 1 MIX_ BTEX_Real sample_ in C5_ 5C Col Temp 001_MIX_ BTEX_Real sample_ in C5_ 5C Col Temp Name Ethylbenzene Benzene Toluene m/p_xylene O-Xylene

37 Reference Gasoil Reference Gasoil - 50 ppm RSD% = 2.2% (10 repetitions) 37

38 Software: Chrom-Card A specific application of Chrom-Card allows automatic integration and reporting The group peak area C7-C40 is calculated The BTEX are individually integrated Benzene Toluene Ethyl-Benzene m,p-xylene o-xylene 38

39 ISO (Mod.): Linearity Test Gasoil Reference Mix - from 2 to 200 ppm 39

40 Sensitivity Reference Gasoil 3µl only! 40

41 Robustness vs dirty matrices System Robustness? 41

42 Robustness vs dirty matrices RSD% Group Peak Real Water Extract After 100 real water extract injections is (10 runs) = 2.3% 42

43 ISO (Mod.): Conventional capillary GC with LVOC Inj Large Volume On Column Injection 50µl injected into a pre-column Automatic OC LV Ultra Fast analysis is 10-fold more productive! 40 min!!! 43

44 Conclusions The analysis of Total Hydrocarbons in water/soil is carried out by Ultra Fast GC in 10-fold shorter run time, still mantaining compliance with ISO (Mod.) and other official methods The Ultra Fast method allows to: - Maximize productivity - Grant top level of repeatability, sensitivity and ruggedness 44