1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB
2、ED HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS (MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 2010 UOP LLC. All rights reserved. Non
3、confidential UOP Methods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at serviceastm.org, 610.832.9555 FAX, or 610.832.9585
4、 PHONE. Total Cycloparaffins and Total Aromatics in Synthetic Paraffinic Kerosene Fuels by Comprehensive Two-Dimensional GC with Flame Ionization Detection UOP Method 965-10 Scope This method is for determining total cycloparaffins (naphthenes) and total aromatics in synthetic paraffinic kerosene fu
5、els (SPK) or petroleum distillates in the boiling range of 69C to 350C using comprehensive two-dimensional gas chromatography (GCxGC) coupled with a flame ionization detector (FID). Molecular type groups are identified by their location, as plotted on a chromatographic contour plot image. The precis
6、ion of this test method has been established for SPK fuels containing from 1.6 to 32.3 mass-% naphthenic hydrocarbons and 0.03 to 1.9 mass-% aromatic hydrocarbons. Alkenes and compounds containing sulfur, nitrogen, and oxygen are possible interferents. References UOP Method 999, “Precision Statement
7、s in UOP Methods,” www.astm.org Zoex GC Image Users Guide, Zoex Technical Note KT030606-1: “What is Loop Modulation?” Outline of Method The sample to be analyzed is injected into a gas chromatograph that is equipped with a two-stage thermal modulator system, “primary” and “secondary” fused silica
8、capillary GC columns and a flame ionization detector (FID). The modulator serves as an interface between the two GC columns. The first “primary” column is a conventional high resolution capillary GC column coated with cross-linked methyl silicone stationary phase, which separates molecules based on
9、volatility. The “secondary” GC column is coated with cross-linked polyethylene glycol; it is short and narrow, for fast GC separations based on the molecular property of polarity. The modulator repetitively accumulates, focuses and re-injects “heart-cut” fractions eluting off the “primary” column on
10、to the “secondary” column, which is connected to the FID. The outcome is a series of high speed 2 of 18 965-10 chromatograms from the “secondary” column which are transformed by computer software into a two-dimensional array, with one dimension representing the retention time from the “primary” colu
11、mn and other representing the retention time from the “secondary” column. Alternatively, the data can be displayed as a 3-dimensional plot containing a third dimension which represents the FID signal intensity. A template is used to identify the boundaries between the different hydrocarbon types and
12、 label the separated components. The mass-% composition of the sample is obtained by internal normalization, wherein the peak volumes are normalized to 100 %. Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used if equiva
13、lent performance can be obtained. Autofill unit, liquid nitrogen level controller with 2 LSI-1 dual level sensors and liquid nitrogen transfer assembly with installed solenoid valve, Zoex Corporation, Cat. No. KT-DWR-AMI24 Balance, readable to 0.1-mg Chromatographic column, “primary”, 50 m of 0.20 m
14、m ID fused silica capillary, internally coated to a film thickness of 0.5 m (bonded) with cross-linked methyl silicone, Agilent Technologies, Cat. No. 19091S-001E. Use of this specific column is recommended. Chromatographic column, “secondary”, 20 m of 0.10 mm ID fused silica capillary, internally c
15、oated to a film thickness of 0.2 m (bonded) with poly (ethylene glycol), Agilent Technologies, Cat. No. 127-7023. Use of this specific column is recommended. Only a portion of the original column is used. See Preparation of GCxGC Fused Silica Column Set in the Appendix for specific instructions. Col
16、umn holder, for mounting secondary column, Zoex Corporation, Cat. No. KT-CLM-ZOE02 Comprehensive two-dimensional GC imaging and data processing software, GC Image, Cat. No. R.2.0. The precision statement of this method was obtained using data processed by this specific software. Computer, suggested
17、minimum hardware configuration: 1000MHz Intel Pentium 4 (or comparable) CPU, 512MB RAM (2GB or more RAM is preferred), 32MB graphics card (128MB is preferred), and color monitor with 1024x768 (or higher) resolution. Processed GCxGC data may require large disk capacity. Cryo cylinder, 230 LP SB, cont
18、ainer for liquid nitrogen, square base, with 22 psi relief valve, Chart Industries, Inc. Storage System Division, Cat. No. 10648556 Data system, electronic, for GC instrument control and data acquisition (i.e. recording detector response as a *.ch file). This device must acquire data at a sufficient
19、ly fast rate (200 Hz) so that narrow peaks typically resulting from use of a capillary column can be accurately measured. Agilent Technologies, ChemStation. Fused silica tubing cutter, ceramic wafer, Agilent Technologies, Cat. No. 5181-8836 Gas chromatograph, temperature programmable, capable of con
20、stant flow, built for capillary column chromatography, utilizing a split injection system, equipped with a capillary injection port with a deactivated glass liner, and a flame ionization detector, Agilent Technologies, Model 7890A, with additional electronic pressure control 3 of 18 965-10 GCxGC the
21、rmal loop modulation system, consisting of a 5-L “secondary” liquid nitrogen dewar, a 30 inch vacuum insulated transfer line, a modulator control module, valve assembly (controlled by valve ports 1 through 4 of the Agilent 7890 valve control bank), and a jet assembly, Zoex Corporation, Model No. ZX1
22、 Leak detector, gas, Restek, Cat. No. 22451 Regulator, air, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tri-Gas, Model 3122-590 Regulator, hydrogen, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tri-Gas, Model 3122-350 Regulator
23、, nitrogen, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tri-Gas, Model 3122-580 Sample injector, syringe or injector capable of introducing a consistent 0.5-L volume of sample. An automatic injection device is highly recommended, although injection can be accompl
24、ished with manual injection with a syringe. The precision of the method is based on instrumentation that is capable of synchronizing sample injection with initiation of the GCxGC modulator. Agilent Technologies, Model 7683B. Reagents and Materials References to catalog numbers and suppliers are incl
25、uded as a convenience to the method user. Other suppliers may be used. Air, zero gas, total hydrocarbons less than 2.0 ppm as methane Autosampler vials, glass, 2-mL volume, 12 x 32 mm, for Agilent autosampler, VWR, Cat. No. HP-5182-0714 Bottles, glass, narrow mouth, round, supplied with fluoropolyme
26、r resin-lined caps, 120-ml, VWR, Cat. No. 16151-060 Caps, for autosampler vials, open hole with septum, screw, 9-mm, with Tef/Sil/Tef liner, VWR, Cat. No. HP-5182-0717 Dichloromethane, ACS reagent, 99.5% pure, VWR, Cat. No. EM-DX0835-8 Gas purifier, air, with 1/8” fittings, to remove moisture from a
27、ir supply, VICI Mat/Sen, Cat. No. P400-1 Gas purifier, hydrogen, with 1/8” fittings, to remove CO, CO2, S, oxygen, non-methane hydrocarbons and moisture from carrier gas, VICI Mat/Sen, Cat. No. P200-1 Gas purifier, nitrogen, with 1/8” fittings, to remove CO, CO2, S, oxygen, non-methane hydrocarbons
28、and moisture from nitrogen supply, VICI Mat/Sen, Cat. No. P300-1 Hydrogen, zero gas, 99.95% minimum purity, total hydrocarbons less than 0.5 ppm as methane Naphthalene, scintillation grade, 99% pure, Sigma-Aldrich, Cat. No. 184500 Nitrogen, zero gas, 99.95% minimum purity, total hydrocarbons less th
29、an 0.5 ppm as methane. It is recommended to use a “house source” that is supplied moisture free, at 70 psi, preferably from a liquid nitrogen boil off source. Nitrogen, liquid, for cryogenic thermal modulation 4 of 18 965-10 Pipette bulbs, VWR, Cat. No. 15001-364 Pipets, disposable, short tip, Paste
30、ur, borosilicate glass, 14.6-cm, VWR, Cat. No. 14673-010 Syringe, for sample injector, 5-L, Agilent Technologies, Cat. No. 5181-1273 Septa, Thermored 11, 11-mm low bleed high temperature, Grace Davison Discovery Sciences, Cat. No. 15132 SilTite metal ferrules, for 0.20-0.25-mm ID capillary columns a
31、nd use with Agilent Ultimate Union, Agilent Technologies, Cat. No. 5188-5361 Synthetic paraffinic kerosene (SPK) reference material. This is a material similar in composition to samples to be analyzed, in sufficient quantity for use for multiple quality control analyses over an extended period of ti
32、me (e.g. year or more). It should be kept in a tightly sealed glass container and stored in a cool dark cabinet when not in use. Petroleum derived kerosene can also be used if similar in composition to samples to be analyzed. This material may need to be spiked with additional pure cycloparaffins or
33、 aromatic compounds to obtain a material similar in composition to the samples to be analyzed. The final composition of the SPK or petroleum derived kerosene reference material shall contain a minimum concentration of cycloparaffins (1 mass-%) and aromatics (0.25 mass-%). Typewriter correction fluid
34、, white, for marking column positions Zero-dead-volume internal union, deactivated, for connecting primary and secondary chromatographic columns, Agilent Ultimate Union Kit contains 1 union, 2 internal nuts, 1 swaging nut and 1 oven wall clip, Agilent Technologies, Cat. No. G3182-61580 Procedure The
35、 analyst is expected to be familiar with general laboratory practices, the technique of gas chromatography, and the equipment being used. This procedure is written for the analyzer listed in Apparatus. If a different instrument is used, modify the procedure as needed. Chromatographic Technique Follo
36、w factory instructions for installation and set up of GCxGC Instrument. The instrument should be operated in an environment with a reasonably constant temperature (30C) and humidity. 1. Install gas purifiers in the gas supply lines between each gas source (air, nitrogen and hydrogen) and their respe
37、ctive inlets to the gas chromatograph. Column life is significantly reduced if gas purifiers are not used. Purifiers should be replaced periodically in accordance with manufacturers recommendations. 2. Mount the GCxGC fused silica capillary column set in the gas chromatograph connecting the “primary
38、” column to the injector inlet and the “secondary” column to the detector inlet. Install the column holder into the modulator assembly. Be sure to cut fresh ends to each column after inserting compression screw and ferrule before connecting columns to the inlet of the injector and the detector. See
39、the Appendix for specific instructions on the preparation of a GCxGC fused silica column set for a Zoex Two-Stage Thermal Loop Modulator System. Zoex Technical Note KT030606-1 illustrates the proper alignment of the column holder in the modulator assembly. 5 of 18 965-10 3. Commence hydrogen carrier
40、 gas flow to the GC. Check for leaks with a leak detector each time a column connection is made and periodically thereafter. CAUTION: Hydrogen carrier gas leakage into the confined volume of the GC column oven can cause a violent explosion. 4. Program the recommended operating conditions as given in
41、 Table 1. Table 1 Recommended Operation Conditions Carrier gas hydrogen Column head pressure 100C 169 kPa gauge (24.54 psig) Mode constant flow Equivalent linear velocity 43 cm/sec Split flow rate 449 mL/min Split flow ratio 100:1 Injection port temperature 260C Column temperature program Initial te
42、mperature 40C Initial time 5 min Programming rate A 1.5C/min Intermediate temperature A 153C Intermediate time A 0 min Programming rate B 2.0C/min Final temperature 250C Final hold time 1.17 min Run time 130 min Hot jet temperature program Initial temperature 120C Initial time 5 min Programming rate
43、 A 1.5C/min Intermediate temperature A 233C Programming rate B 2.0C/min Final temperature 250C Valve assembly Agilent 6890 valve port 1 power for modulation control Agilent 6890 valve port 2 hot jet Agilent 6890 valve port 3 cold jet Agilent 6890 valve port 4 power for control of liquid nitrogen Det
44、ector flame ionization Temperature 260C Hydrogen flow rate* 40 mL/min Air flow rate* 450 mL/min Makeup gas nitrogen Makeup gas flow rate 35 mL/min Mode constant makeup flow Sampling rate 200 Hz Sample size 0.5 L *Consult the manufacturers instrument manual for suggested flow rates. 6 of 18 965-10 Ot
45、her conditions may be used provided they produce the required sensitivity and chromatographic separations equivalent to those shown in the Typical Chromatograms (Figures 2-4). 5. Set the column oven temperature initially to 250C. Maintain this temperature until a stable baseline has been obtained at
46、 the required detector sensitivity. 6. Cool the column oven to a stabilized 40C. 7. Set the modulator control module parameters as listed in Table 2. Table 2 Modulator Parameters Duration of modulator hot jet pulse 300 ms Modulation period 6000 ms Rephase negative 8. Start the modulator control modu
47、le. 9. Turn on the autofill unit to start flow of liquid nitrogen to the GCxGC loop modulation system. Once the secondary liquid nitrogen dewar is filled to the appropriate level one can begin sample analysis. Follow the manufacturers recommended conditions for setting and controlling the liquid nit
48、rogen autofill unit. Tuning the GCxGC Instrument (Optimizing 2nd dimension GC column length and software volume filter setting) 1. Prepare a solution of 0.5 mass-ppm naphthalene in dichloromethane. This is best prepared by serial dilution until the desired concentration is obtained. For example, wei
49、gh 0.1 gram of naphthalene to the nearest 0.001g in a 120-ml glass bottle. Dilute with dichloromethane to a final weight of 50 g; cap and mix thoroughly to create a 0.2 wt-% mixture of naphthalene in dichloromethane. With a Pasteur pipette, weigh a 0.1 g aliquot of the mixture to the nearest 0.001 g in a separate 120-ml glass bottle. Dilute with additional dichloromethane to a final weight of 40 g; cap and mix thoroughly to create a 5-wt-ppm mixture of naphthalene in dichloromethane. With a Pasteur pipette, w
