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 2011 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. Organic Analysis of Distillate by Comprehensive Two-Dimensional Gas Chromatography with Flame Ionization Detection UOP Method 990-11 Scope This method is for organic analysis of distillate or petroleum fractions boiling in the range of 36 435C using comprehensive two-dimensional gas chromato
5、graphy (GCxGC) coupled with a flame ionization detector (FID). Results, expressed in mass-% can be reported in three different formats: 1) molecular types indexed to n-alkanes; 2) molecular type homologous series by carbon number and 3) user specified resolved compounds or molecular type groups. Ind
6、ividual compounds and molecular type groups are identified by their location, as plotted on a chromatographic two-dimensional image. Olefins, unless specifically identified, are lumped with other molecular types, typically cycloparaffins. Heteroatomic species, when resolved, can be determined; other
7、wise they are lumped with other aromatic hydrocarbons. The lower limit of detection for a single molecular component is typically below 0.004 mass-% with the specified equipment. References Scanlon, J. T. and Willis, D. E., Journal of Chromatographic Science, 23, 333-340 (1985) UOP Method 999, “Prec
8、ision Statements 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 “secondar
9、y” fused silica open tubular capillary GC columns and a flame ionization detector (FID). The modulator serves as an interface between the two GC columns. The primary column is a conventional high resolution capillary GC column coated with a cross-linked methyl silicone stationary phase, which separa
10、tes molecules based on volatility. The secondary GC column is coated with cross-linked poly (ethylene 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
11、 the primary column onto the secondary column, which is connected to the FID. The outcome is a series of high speed 2 of 48 990-11 chromatograms from the secondary column which are transformed by computer software into a two-dimensional array and displayed as a two-dimensional image, with the x-axis
12、 representing the retention time from the primary column and the y-axis 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 th
13、e boundaries between the different hydrocarbon types and 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 t
14、o the method user. Other suppliers may be used if equivalent performance can be obtained. The GCxGC-FID instrument items listed below are specifically for the “ZX1-thermal modulator” instrument commercially available from Zoex Corporation. Analytical balance, readability 0.0001 g Chromatographic col
15、umn, primary, 50 m of 0.20 mm 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 sili
16、ca capillary, internally coated 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. Note: Only a portion of the original column is used. See Preparation of GCxGC Fused Silica Column Set in the Appendi
17、x for specific instructions. Column holder, for mounting secondary column used specifically in a Zoex two-stage cryo loop modulator, Zoex Corporation, Cat. No. KT-CLM-ZOE02 Comprehensive two-dimensional GC imaging and data processing software, GC-Image V2.1, Zoex Corporation. The precision statement
18、 of this method was obtained using data processed by this specific software. Cryo auto-fill unit, liquid nitrogen level controller with two LSI-48 dual level sensors and liquid nitrogen transfer assembly with installed solenoid valve, Zoex Corporation, Cat. No. KT-DWR-TRG24 Cryo cylinder, 230 LP SB-
19、 square base with 22 psi relief valve, container for liquid nitrogen, Chart Inc., Storage System Division, Cat. No. 10648556. This is not needed if there is instrument access to a laboratory supplied liquid nitrogen distribution system. Data system, electronic, for GC instrument control, data acquis
20、ition and data processing. This device must acquire data at a sufficiently fast rate (200 Hz) so that narrow peaks typically resulting from use of a capillary column can be accurately measured. The suggested minimum computer configuration: Microsoft Windows operating system (e.g. Windows XP, Vista o
21、r Windows 7), 1000 MHz Intel Pentium 4 (or comparable) CPU (dual-core is preferred), 1 GB RAM (2 GB or more is preferred), 128 MB OpenGL-capable graphics card (256 MB is preferred), and color monitor with 1024x768 (or higher) resolution. Processed GCxGC data may require large disk capacity. It is id
22、eal to have two data systems: one for instrument control and data acquisition and a separate one for data processing. The data acquisition software must allow data to be exported in a format compatible with GC-Image software. Several formats that have been verified to work are 3 of 48 990-11 *.ch (A
23、gilent ChemStation IQ Data File Format); ASCII csv (Comma-Separated-Values in text format); and PEG (LECO file format for collected raw FID data). Excel 2003 or later, software, Microsoft Fused silica tubing cutter, ceramic wafer, Agilent Technologies, Cat. No. 5181-8836 Gas chromatograph, temperatu
24、re programmable, capable of constant 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 c
25、ontrol GCxGC two-stage thermal modulation system, consisting of a secondary liquid nitrogen dewar, a 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
26、No. ZX1; or equivalent. This method is written specifically for GCxGC-FID instruments containing two-stage thermal modulators that use liquid nitrogen as a cryo medium. Zoex and LECO both offer Agilent GC instruments configured with this type of modulation system. Other modulation systems such as “c
27、onsumable free thermal” or “capillary flow” modulators may be limited in scope and have not been evaluated by this method. Leak detector, gas, Restek, Cat. No. 22451 Refrigerator, flammable-materials storage, Fisher Scientific, Cat. No. 97-938-1 Regulator, air, two-stage, high purity, delivery press
28、ure 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, nitrogen, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tri-G
29、as, Model 3122-580 Sample injector, autosampler or injector capable of introducing a consistent 0.1-L volume of sample. The use of an automatic injection device is required to achieve necessary repeatable injection timing. The precision of the method is based on instrumentation that is capable of sy
30、nchronizing sample injection with initiation of the GCxGC modulator. Agilent Technologies, Model 7683B. Reagents and Materials References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Air, zero gas, total hydrocarbons less than 2.0 pp
31、m as methane Autosampler vials, glass, 2-mL volume, 12 x 32 mm, for Agilent autosampler, VWR, Cat. No. HP-5182-0714 Bottle, 120-mL, with fluoropolymer-lined cap, VWR, Cat. No. 16151-286 Caps, for autosampler vials, open hole with septum, screw, 9-mm, with Tef/Sil/Tef liner, VWR, Cat. No. HP-5182-071
32、7 Dichloromethane, ACS reagent, 99.5% pure, VWR, Cat. No. EM-DX0835-8. CAUTION: Dichloromethane is a known carcinogen. All operations involving its use must be performed in a properly ventilated area, while wearing appropriate personal protective equipment. 4 of 48 990-11 Distillate reference materi
33、al. This should be a wide boiling range material (ideally 36C - 435C) containing significant concentrations of n-paraffins, mono-, di-, tri- and 4 plus ring aromatics. It should be of a sufficient quantity for use for multiple quality control analyses over an extended period of time (e.g. year or mo
34、re). Keep in a tightly sealed glass container stored in a cool dark cabinet when not in use. NIST SRM 1624d is an example of a commercially available material which is suitable for a Distillate Reference Material. Ferrules, vespel/graphite 85%/15% (short) for 0.10-0.25-mm ID capillary columns for us
35、e in connecting secondary column to flame ionization detector, Agilent Technologies, Cat. No. 5181-3323 Gas purifier, air, with 1/8” fittings, to remove moisture from air supply, VICI Mat/Sen, Cat. No. P400-1 Gas purifier, hydrogen, with 1/8” fittings, to remove CO, CO2, S, oxygen, non-methane hydro
36、carbons 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 and moisture from nitrogen supply, VICI Mat/Sen, Cat. No. P300-1 Hydrogen, zero gas, 99.95% minimum purity, total hydrocarbons less
37、than 0.5 ppm as methane Nitrogen, zero gas, 99.95 % minimum purity, total hydrocarbons less than 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 modulat
38、ion. Liquid nitrogen is typically supplied with a larger nitrogen dewar or plumbed laboratory supply. Pipette bulbs, VWR, Cat. No. 15001-364 Pipets, disposable, short tip, Pasteur, borosilicate glass, 14.6-cm, VWR, Cat. No. 14673-010 Pyrene, sublimed, 99% pure, Sigma-Aldrich, Cat. No. 571245 Syringe
39、, 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 and use with Agilent Ultimate Union, Agilent Technologies, Cat.
40、 No. 5188-5361 Typewriter correction fluid, white, for marking column positions Zero-dead-volume ultimate 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 Techno
41、logies, Cat. No. G3182-61580 Procedure Preparation of the GCxGC Instrument The analyst is expected to be familiar with general laboratory practices, the technique of gas chromatography and the equipment being used. Follow the manufacturers instructions for installation and set up of the GCxGC instru
42、ment. The procedure is written specifically for GCxGC-FID instruments containing two-stage thermal loop modulators that use liquid nitrogen as a cryo medium (see Apparatus). If a different instrument is used, modify the procedure as needed. The 5 of 48 990-11 instrument should be operated in an envi
43、ronment with reasonable constant temperature (30C) and low relative humidity (50%). 1. Install gas purifiers in the gas supply lines between each gas source (air, nitrogen and hydrogen) and their respective inlets to the gas chromatograph. Column life is significantly reduced if carrier gas purifier
44、s are not used. Purifiers must be replaced periodically according to manufacturers recommendations. 2. Mount the GCxGC fused silica capillary column set in the gas chromatograph connecting the primary chromatographic column to the injector inlet and the secondary chromatographic column to the detect
45、or inlet. Appendices A and B provide specific instructions for column installation of Zoex and LECO instruments, respectively. 3. Commence gas flows to the GC instrument. Check for leaks with a leak detector each time a gas or column connection is made and periodically thereafter. If a leak occurs t
46、he column set must be reevaluated and a new fresh connection must be made. CAUTION: Hydrogen carrier gas leakage into the confined volume of the column oven can cause a violent explosion. It is, therefore, mandatory to check for leaks each time a connection is made and periodically thereafter. A lea
47、k will allow oxygen into the column, which can lead to degradation of the stationary phase and reduce GC column performance. 4. Program the recommended operating conditions as given in Table 1. Other conditions may be used provided they produce the required sensitivity and chromatographic separation
48、s equivalent to that shown in a Typical Chromatogram (Figure 3). Table 1 Recommended Operation Conditions Carrier gas hydrogen Mode constant flow Flow rate 1.5 mL/min Column head pressure 40C 170 kPa gauge (25 psig) Split flow rate 150 mL/min Split flow ratio 100:1 Injection port temperature 280C Co
49、lumn temperature program Initial temperature 40C Initial time 10 min Programming rate A 1.5C/min Intermediate temperature A 153C Intermediate time A 0 min Programming rate B 2.0C/min Final temperature 280C Final hold time 11.17 min Run time 160 min Hot jet temperature program Initial temperature 120C Initial time 10 min Programming rate 1.5C/min Final temperature 280C Final hold time 70 min Valve assembly Agilent 6890 valve port 1 power for modulation control 6 of 48 990-11 Agilent 6890 valve port 2 hot jet Agilen
