SOP for Operation of Gas Chromatography Headspace System (Agilent-6797A)

Purpose

To develop the standard Operation procedure for GC-HS; Agilent 6797A and its compliance with the provision of Good laboratory practice regulations. 

Scope

Describes the finest details of the steps to be followed for the simplest and most precise handling of the machine and analytical technique 

Responsibilities

All the staff members carrying out the operation of GC-HS; Agilent is responsible for strictly adhering to the procedure given. 

Procedure: 

Cold Start of Gas Chromatography Headspace Instrument 

• Before starting the instrument, switch “On” the air conditioning in the room. 
• Switch “On” all the gases (Nitrogen, Hydrogen & Zero air) by pushing the valve up on Gas Panel. 
• Switch “On” the main UPS by long pressing start/stop button for 3 seconds. Before starting the GC Instrument, check the voltage stability (Voltage should be #233V). 

• Switch “On” the GC instrument by pressing the button on the lower left corner. 
• Similarly, switch “On” the HS instrument by pressing the button on the lower left corner. 
• Switch “On” the CPU of the computer. 
• As the system loads, from the desktop, select ‘GC’ from Administrator and GC. 

Preparation of Sample and Standards for Analysis 

Preparation of Standard 

• From the standard GC grade analyte (99.95% GC grade), pipette 1ml and dilute the analyte in 100ml Ultra-pure water. 
• Pipette out serial dilutions of 2000µl, 1000µl, 500µl, 250µl, 100µl, from stock solution of 1ml/100ml and dilute in 10ml of Ultra-pure water. 

Preparation of Internal Standard 

• From the standard GC grade analyte (n-propanol), pipette 300µl and dilute the analyte in 100ml distilled water. 
• Take 90µl of internal standard in the vial along with Standard and Sample if required. 

Sample Preparation 

• In a clean, dry 20 ml HS vial take 1000µl/1ml of liquid analyte. 
• If required as per analytical conditions, add 90µl of Internal Standard (n-propanol). 
• Seal the mouth of vial using fresh PTFE septa and metallic crimp. 
• Shake the vial slowly to mix sample and standard. 

Creating New Method for Analysis 

Creating New Method 

• On the Desktop, Double click on the “Instrument1 online” icon; the Method and Run Control screen will appear. 2. From the Menu bar click on “Method”, from the drop-down list select “New Method”.

Creating Calibration of a Method 

• Successively run samples of serial dilutions; 2000µl, 1000µl, 500µl, 250µl, 100µl in a sequence. 
• Double-click on the “Instrument 1 offline” icon on the desktop; the Data analysis screen will appear. 
• From the Menu bar click on “Method”, from the drop-down list select “Load Method”. From the list, select the method on which calibration is to be drawn. 
• Select the graph of maximum concentration and load. 
• On the “Menu bar” click on “Calibration”, from the drop-down list select “New Calibration Table”. 
• “Calibrate: Instrument 1, New Calibration Table” window will appear, click on “OK”. 
• All the peaks appear highlighted and table appears with RT and area. 
• For every peak specify “Name” and “Amount”. 
• For next dilution, from the “Menu bar” click on “Calibration”, from the dropdown list select “Add Level”. 
• Specify only the amount. After all concentrations have been labelled, click on “OK”. 
• From the Menu bar click on “Method”, from the drop-down list select “Save Method”. 

ALSO READ: SOP for HPLC System Using Chemstation Software from Agilent

Operation of Gas-Chromatography Headspace System 

• Double-click on the “Instrument 1 online” icon on the desktop; the Method and Run Control screen will appear. 
• From the Menu bar click on “Method”, from the drop-down list select “Load Method”. 
• Run the “CONDITIONING.M” method for at least 30 minutes before analyzing any sample.

Analyzing Sample on GC-HS 

• From the Menu bar click on “Method”, from the drop-down list select “Load Method”. From the list, select the method to be run (recent calibration method), and click ‘OK’. 
• From the Menu bar click on “Sequence”, from the drop-down list select “Sequence Table”. 
• On the Sequence Table: Instrument1 window, fill the following data of 

1. Vial position where vial is kept 
2. Sample Name ID of the sample to be analyzed 
3. Method name Method on which sample is to be analyzed 
4. Inj/vial Always “1” 
5. Sample type Sample/ Standard 

• For every next line, press down key. 
• For every vial in the carousal, information should be filled up. 
• Start sequence by clicking on “Run Sequence” or by pressing F6. 

Viewing Report of Sample Run 

• On the Desktop, Double click on the “Instrument 1 offline” icon on the desktop; Data analysis screen will appear. 
• From the Menu bar click on “Method”, from the drop-down list select “Load Method”. From the list, select the method to be loaded. 
• From “Data Analysis” window, on the left side of the screen, select the sequence run. 
• Load the graph. 
• From the Menu bar click on “Report”, click on “Print Report”. 
• View report and print if required.

Shut Down of Gas Chromatography Headspace Instrument 

• On the Desktop, Double click on the “Instrument1 offline” icon. From the Menu bar click on “Method”, from the drop-down list select “Load Method”. From the list, select the “COOLING.M” method. 
• As soon as the Detector temperature of the GC system and the Oven temperature of the Headspace system acquires a temperature below 50°C, close the “ChemStation Online” or “Offline” windows. 
• Switch “Off” the Instruments by pressing the button at the left-down corner. Push the valve down for gases (Nitrogen, Hydrogen & Zero Air) from as panel. 
• Press the “Start/Stop” button on the UPS, and wait till the supply becomes zero. 
• Switch “Off” the Air conditioners of the room. 

ALSO READ: SOP for Operation and Calibration of Gas Chromatography (CHEMITO-7610 ECD)

FITTING OF NEW COLUMN FOR ANALYSIS 

Fitting New Column in Oven Compartment 

• Open the Oven compartment, ensuring that the system is cooled and not in working condition. 
• Open the nut of the Inlet and Detector with a spanner. 
• Insert the new column within the hanger in the oven. Take one end of the column to be fixed in the Inlet end and the other at the Detector bend. 
• To fix the Inlet end, cut the capillary column at about a length of 1mm with the help of a cutter. Insert a septum and ferrule leaving a length of 4mm-6mm from the tip. 
• Insert the column tip in the Inlet end, leaving a distance of 1mm from the top. Seal the attachment by screwing the nut using a spanner. 
• Similarly, seal the detector end by cutting the capillary column at about a length of 1mm with the help of cutter. Insert a septa and ferrule leaving a length of 4mm-6mm from tip. 
• Insert the end in detector, leaving a tip of 1mm and seal using spanner.

Configuring New Column

• From the Menu bar click on “Method”, from the drop-down list select “Load Method”. From the list, select the method on which new column is to be configured. 
• On the Menu bar click on “Edit Instrument Parameters”, Setup Method window will appear. 
• Select 7690A (GC Sampler), different conditions of Auto sampler; Column; Oven; Inlet; Detector etc. will appear. 
• Click on “Column”, and column conditions will appear. 
• Click on “Show All Columns”, list of columns appears. Select your column specifying the Identification and its length etc. Click on “Install”, and specify Inlet and Outlet. 
• Click on “Calibrate Column”. 
• Click on “OK” and save method changes. 
• Run the Conditioning method for 1 hour before running any sample on a new column. 

Revision History

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