5890II GC Standard Operating Procedure 9/2/2005

Transcription

1 5890II GC Standard Operating Procedure 9/2/2005 This procedure is for the analysis of natural gas using the HP 5890II GC with the Restek ShinCarbon column. Detector Type: TCD Column Type: Restek Micropacked, ShinCarbon ST 100/120 1 meter, 0.75mm ID, 0.95mmOD, Silco Max Temp 330 degrees C Injector type: Packed purged inlet. Injector used: B - Injector A is broken Detector used: A TCD Gasses used: Helium Helium is the carrier gas; this is the gas that carries the injected material through the column. Helium is also used to provide Makeup gas, also known as Aux gas. Makeup gas is added at the end of the column to increase the gas flow entering the detector. Reference gas is helium. Reference gas is compared with the sample at the detector. 1. Turn on the power The power switch for the GC is on the lower right side towards the back of the GC. 2. Open Gas Valve: Do not adjust the cylinder regulator valves! Open the Helium main valve on the tank labeled 5890 one turn counterclockwise. Some gasses have a small valve on the outlet side of the regulator this valve should be open. Helium Tank Pressure U> 500U Outlet Pressure U45 60 PSIU If the pressure readings are out of range consult the lab manager. Do Not Adjust! Make sure the (He) toggle switch located to the left of the GC on the HP 5890 II GC gas switch panel is set to the horizontal position.

2 3. Set gas flow. Gas flow rates should be preset. Consult lab personnel if you have questions about gas flow. DO NOT ADJUST GAS FLOW. Column flow = 8 10 ml/min. Aux gas + column flow = 9 15 ml/min. Measure as combined flow. Set Reference Gas: Reference Gas should be ml/min. (Column flow + Aux Gas + Reference Gas) = ml/min. 4. Measure column gas flow: Verify Helium Flow. Do not adjust flow rates. Verify Helium flow through the column by measuring the flow at detector A using the gas flow meter or a glass bubble type flow meter. Caution! Detector is HOT. Column flow which is helium flow rate with REF AND AUX GAS OFF should be between 8 and 10 ml/min. The recommend starting value is 10ml/min. 5. Open AUX gas valve for TCD detector (A) 2 to 3 turns. Valve is located on upper left hand area of GC. Verify reference gas valve located below AUX valve is off. Measure combined flow of column flow and aux gas. Flow should be within 9 15 ml/min. 6. SET REFERENCE GAS: Open reference (REF) gas valve. Reference gas should be 20 to 50 % higher than column flow, approximately ml/min. Measure this as a percentage of total flow. Total flow with Column Gas + Aux Gas + Reference Gas = ml/min. 7. Once gas flow is set turn on TCD detector. DET, ON. 8. Start Software: a. Log on to computer (This Computer), NOT CHE - using the user log on, GC analysis: Password = GCuser b. Open Chrom Perfect software from the desktop. c. Select Acquisition to acquire data. d. Under the (Control) section claim the instrument you wish to use. Note the detector type for each instrument is indicated under the (instrument name) heading. e. Locate the (Status) and (Selection) tabs on the right hand side of the screen. Select (Status) and click on the (Control) icon to bring up the instrument control panel.

3 f. From the instrument control panel select (Download). This opens the Acquisition Parameters window. You can select the Method file in this window. Edit the base name as desired. Use the NatGasB.met for the 5890 II, TCD detector running natural gas, propane or other flammable gases. Select the (Tutorial.MET) for injecting hydrocarbons using the 5890A, FID detector. g. The 5890II (TCD) will automatically start the Chrom Perfect software when the start button on the GC is depressed. The 5890A requires the user to start the software using the (Start Run) icon on the instrument control window. When running the 5890A start the software immediately injecting your sample. h. Once the analysis is running the plot display will appear. You can edit the scale and run time or stop the run by right clicking within the plot and selecting the desired parameter. i. When the run is complete go to the desktop and select (Analysis) from the main Chrom Perfect menu. The data is stored is C:\CPData\GC Student Data\ (description of GC & detector). All files have the.raw extension. j. Select the icon to the right of the drop down icon. This will display a list of files. The most recent file is at the top of the list. Open your file and edit as needed. Select (Integration), click on (Report) to generate a report of your chromatograph. Temperature: Temperature will affect gas flow. Bring injector, oven and detector to set point temperatures before measuring gas flows. Temperature set points will depend on the type of analysis you are doing. See supplemental information for further guidelines on temperatures. Recommended starting temperatures for volatile gases are list below. Detector = < Max column temperature (Recommended temp = 100degrees C) Injector = degrees C Oven = degrees C IF NOT READY LIGHT IS ON: SET DETECTOR B TO OFF, SET BOTH SIGNALS TO DETECTOR A. The not ready light will go off when the heaters have reached their set point and the TCD detector is on. Once flow of carrier gas through the column is confirmed turn on the 3 heaters for the GC. The controls for all the heaters are located on the upper two rows of the right front control panel. Press INJ A TEMP The digital display shows the temperature of injector A, it is normally about room temperature. To the right of the temperature reading is the on/off indication. Be sure the injector and detector you are using is set to on. First press the ON button on the keypad then if the set point is not the one you want you may press the numbers for the desired set point then ENTER to change it.

4 The second heater is for the oven. Press the OVEN TEMP button then press the ON button. If you need to adjust the set point do it in the same manner as the injector heater. The third heater is for the detector. You will be using detector B on this GC. Press the DET B TEMP button then press the on button. You may adjust this in the same manner as the other two heaters. If the GC has not been used for a few days it is good practice to set the oven temperature at 300 degrees C and let the column cook for minutes. Set Temperature Ramp: For this lab the recommended range for initial temp is 40 to 120 P PC. To set up a program that is not isothermal press the INIT TIME button and enter the time you would like the oven to remain at the initial temperature. For this experiment start with a value of 2 minutes. To set the rate of the ramp press the RATE button and enter the rate. The recommended starting value is 12 degrees per minute. Set the FINAL VALUE button to set the desired final temperature. The recommended final temperature is 300 degrees C. Set the amount of time you want to oven to remain at the final temperature. FINAL TIME, enter value for final time. Recommended final time = 10mins. o Injection Guidelines Wear safety glasses. Use a gas syringe not a liquid syringe. Hold the needle above injection port A. Don t touch the port since it may be hot. Keep your thumb above the plunger in case the pressure pushes the plunger up. Then push the entire needle straight down through the plunger until you can t go any further. Then push the plunger down and pull the whole syringe out. Immediately press the start button on the GC and the program will begin. SHUTDOWN Turn off the oven heater. Turn off the injector heater. Turn off the detector heater.. Press the DET button and turn the detector off. Allow the GC oven to cool to room temperature, then turn the Helium gas off at the tank. If the GC is not cool Oxygen will get in the column and destroy the inner coating of the column. If the GC is not cool leave the helium on. Turn OFF GC.

5 Chrome Perfect Tips: Data for the HP 5890 II is stored in C:\CPData\GC Student Data\5890II TCD Data Data for the HP 5890A is stored in C:\CPData\GC Student Data\ 5890A FID Data Data for the GOW-MAC is stored in C:\CPData\GC Student Data\GOW MAC Data To zoom in on selected peaks right click and select peaks of interest then left click to view. To return to normal view left click and select undo expansion. To remove baseline noise select integration Auto then enter a number greater than zero in the threshold window. Other options available by selecting integration manual.