SOP FOR OPERATION AND CALIBRATION OF GAS CHROMATOGRAPHY

1. OBJECTIVE:

1. To lay down the procedure for Operation & Calibration of Gas Chromatography 

2. SCOPE: 

1. This procedure is applicable for the Operation & Calibration of Gas Chromatography 

3. RESPONSIBILITY:

1. Quality Control Officer / Executive are responsible to follow procedure as per the procedure mentioned in this SOP. 

2. QC Head is responsible for implementation and compliance of the procedure as per this SOP.

4. ABBREVIATIONS

1. SOP    :    Standard Operating Procedure

2. QC    :    Quality Control

3. STP    :    Standard Test Procedure.

4. N2        :    Nitrogen Gas

5. HS        :    Head Space

6. GC    :    Gas Chromatography 

7. IPA    :    Isopropyl Alcohol

8. ID        :    Internal Diameter or Identification Code

9. QCO    :    Quality Control Officer 

5. PROCEDURE: 

1. Procedure For Operation

2. Starting The Instrument

1. Switch on the following:

Gas chromatograph,/Head space sampler (for HS GC) and Data processing unit (Computer).

2. Open the N2 (carrier gas) valve.

3. Column Installation

1. Allow the oven temperature, detector temp, injector temp. to cool below 50°C.

2. Replace septa and liner if required.

3. Switch off the oven temperature. Open the door of GC oven. 

4. Make both the column ends flat using cutter if required.

5. Put the column from injector side while keeping the other end open and purge N2 for a few seconds.

6. Confirm the N2 flow from the other end by dipping it in 1: 1 mixture of Methanol / IPA and water. Bubbles must form at the outlet.

7. Insert the other end of column from detector side and ensure tightness at both ends using spanner. Check the leakage from both ends using 1:1 mixture of Methanol / IPA and water and shut the door.

4. Column Conditioning

1. Open Zero-Air valve first then the valve of Hydrogen completely. 

2. Optimize flow ratio of zero air and hydrogen, it shall be about 400: 40.Use flow meter to adjust the flow.

3. Press the ignition button to ignite the flame with the help of lighter.

4. Put the column on heating with in the maximum temperature limit column till the signal becomes stable.

5. Method Loading From Software GC Solution

1. Open Zero-Air valve first then the valve of Hydrogen completely. 

2. Select the option window GC solution. Select instrument No.

3. Entering the User ID & Password and press OK Key.

4. Click in the following order FILE / LOAD / METHOD.

5. To load method choose the path D:\METHOD\PROJECT\METHOD DOWNLOAD Enter Sample Information.

6. Click at run control, then at sample information to enter following information:

7. Sample name with Batch No.

8. Comments W.R.T. Project / Product / Test name

9. Enter Headspace parameters (if headspace is attached).

10. After loading various vials for blank, standard and sample into the magazine. Enter the following manually as per the required STP using the front key panel available on the headspace.

Zone temperature 

Event time

Vial parameter

11. STARTING AND STOPPING THE RUN.

12. Press the start button from headspace key panel or directly from GC key panel (if headspace is not included).

13. After completion take out the prints of the report generated.

14. Do the calculation as per formula given in the concerned STP.

15. In case any problem / clarification contact LAB In-charge.

6. Calibration of GC

1. The QCO shall enter the calibration record as per Calibration of Gas Chromatograph (Annexure I).

7. System Calibration

1. To check the reproducibility and detectability of the system, perform the following experiments.

8. Test Column

1. Fused Silica wide bore capillary column (30 x 0.32mm ID) coated with 0.25µm of 5% Phenyl- 95% polysiloxane (Agilents HP-5 column).

        Note: It is Preferable to use one dedicated column for the purpose. 

9. Test Mixture

1. Prepare sufficient quantity of solution containing about 1.0 mg/ml each of Tetradecane, Pentadecane & Hexadecane in dichloromethane. 

2. Injection volume: Inject 1 µl with 10 µl syringe.

3. Number of Injection : Six (1 Blank + 5 Test) 

10. GC Parameters 

Initial oven temperature    :    150°C

Initial time            :     0 min 

Rate            :      10°C / min

Final oven temperature    :      200°C 

Hold time            :      2 min

Flow rate             :    2 ml/min. 

Injector temperature     :      250°C

Detector temperature                :     270°C 

Carrier flow (N2)                     :      10 ± 1.0 ml/min

Hydrogen flow        :    40 ± 4 ml/min

Zero air flow        :    400 ± 40 ml/min

1. The relative retention times are as follows:

Compound name                        :       Relative retention time

Dichloromethane                       :    ~ 0.19   

Tetradecane                               :       ~ 1.00

Pentadecane                              :       ~ 1.20

Hexadecane                               :      ~ 1.50

2. Set the integration parameters accordingly and proceed with integration and take the prints of the reports generated.

3. Acceptance Criteria for Calibration.

4. The percentage relative standard deviation (%RSD) of the ratio of area counts of the peaks corresponding to pentadecane and Hexadecane to that of Tetradecane in the chromatograms of five replicate injections should not be more than 3%.The percentage relative standard deviation (%RSD) of retention times (RT) of the analytes in the five replicate injections should not be more than 2%.

11. Calibration of Head Space Analyzer

1. Test Column :  

Fused Silica wide bore capillary column (30 x 0.32mm ID) coated with 0.25µm of 5% Phenyl-95% polysiloxane (Agilents HP-5 column)

2. Test Mixture:  

Prepare 0.4%v/v of Ethanol in water (1ml ethanol dilute to 250ml with distilled water).

3. Test Volume:

Prepare 5 vials each containing 2 ml test solution. Seal the vial with butyl rubber septa and place in the headspace magazine.

4. GC Parameters:

Oven temperature (Isothermal)     :    80°C

Time            :     20 min 

Injector Temperature         :      120ºC

Detector Temperature               :     200°C 

Carrier Gas                              :      Nitrogen

Carrie Gas Flow        :    3.0 ml ± 0.1 ml/ min

Range            :    1

Attenuation            :    1

    Carrier Gas Pressure        :    15 psi

    Split Ratio            :    20:1

5. Head Space Parameters:

Sample Temperature        :    100°C

Needle Temperature        :     105ºC 

Transfer Line Temperature     :      110ºC

Thermostating Time        :    22 min

GC Cycle Time        :    25 min

Pressurization Time        :    3.0 min

Injection Time            :    0.04 min

Withdrawal Time        :    0.5 min 

6. Acceptance Criteria

7. For capillary column : The percentage relative standard deviation (%RSD) of the area counts of the peak corresponding to ethanol should not be more than 5.0% (Five replicate injections) and the percentage relative standard deviation (%RSD) of retention times (RT) of analytes in the five replicate injections should not be more than 2.0%

8. Calibration Frequency : Half Yearly 

9. REMARKS:

If the instrument fails calibration or in the event of a malfunction, report the same to the In-charge, and lodge a complain with the service engineer.

6. ANNEXURES/REFERENCES :

1. Annexure I : Calibration of Gas Chromatography.