Gas chromatography–mass spectrometry Calibration Procedure
Check
parameters |
Acceptance
criteria |
Mass Sensitivity |
S/N Ratio
> 60:1 |
Repeatability-RT GC-MS/MS FID &
ECD |
% RSD MAX
0.5 % 2.0 % |
Repeatability-Area
GC-MS/MS FID & ECD |
% RSD MAX
5 %
3 % |
Detector linearity
|
R² ≥ 0.99
|
Split Ratio
|
R² ≥ 0.99
|
Carry-over
|
Height should be less than 0.4% |
Sensitivity (GC-MS)
- Check the Autotune, Self-calibration and save the calibration details.
- Prepare the standard octafluoronaphthalene (OFN) in the concentration of 1 pg/ul in iso octane in suitable sample vial.
- Inject octafluoronaphthalene and run the GCMS.
- Check the signal noise ratio and mass spectrum of the OFN.
Acceptance
EI Sim Or MRM: S/N> 60 octafluoronaphthalene for 10 ppb molecular ion at m/z 272.
Repeatability
Instrument |
Details |
Acceptance
criteria |
GC-MS |
Lindane is
taken for calibration of Gc-Ms. Other Gc compounds of known purity can also
be selected as reference material. Prepare 100 μg
/ml from the stock solution. Inject 5
replicates and calculates the % RSD for the Retention time and Area. |
% RSD for Retention time should be ≤ 0.5 %
% RSD for Area Should be ≤ 0.5 % |
GC-FID |
Prepare 10%
ethanol in water. Stock volume and final volume can be changed depending on
the availability of micro pipette and volumetric flask. Inject 5 replicates
and calculates the % RSD for the Retention time and Area. |
% RSD for Retention time should be ≤ 2 %
% RSD for Area Should be ≤ 3 % |
GC-ECD |
Prepare 100 μg/ml
of lindane in ethyl acetate and Inject 5 replicates and calculates the
% RSD for the Retention time and Area. |
% RSD for Retention time should be ≤ 2 %
% RSD for Area Should be ≤ 3 % |
Detector Linearity
Instrument |
Linearity |
GC-MS |
Prepare 20, 40, 60, 80, 100 ng/ml lindane Calibration
Solution and inject. Plot linearity graph between concentration on the X axis
and Area on the Y axis. |
GC-FID |
Prepare 0.5, 1, 5, 10, 25, 50 % ethanol in water and inject
in GC-FID. Plot linearity graph between concentration on the X axis and Area
on the Y axis. |
GC-ECD |
Prepare 20, 40, 60, 80, 100 ng/ml lindane in ethyl
acetate and inject in GC-ECD. Plot a linearity graph between concentration on
the X axis and Area on the Y axis. |
Acceptance criteria
The correlation coefficient r2 obtained from the
linearity graph for different levels should not be less than 0.99
Split Ratio (Gc-Ms)
Inject same concentration of standard soln at
different split ratio as 1:10, 1:50, 1:100 and record the chromatogram for each
split ratio. Plot a linearity graph between ratio on the X-axis and area on the
Y-axis.
Acceptance criteria
The correlation coefficient r2 obtained from the
linearity graph for split ratio should not be less than 0.99
Carry Over (GC-MSMS, GC-MS, GC-FID, GC-ECD and Head Space)
Keep the vials Containing solvent and analyte in solvent in
the following order.
Vial No. |
Position
given for reference, |
Sample
Details |
1. |
10 |
Solvent |
2. |
11 |
Std. in
Solvent |
3. |
12 |
Solvent |
Calculate the percentage of carry over as following
Carry Over (%) = HCo *100 / Hi
Where
HCo - peak
height of analyte from vial 12.
Hi - peak
height of analyte from vial 11.
Acceptance criteria
Height should be less than 0.4%
Head Space
Inject 1 mg/l hexane in oil in 5 replicates and calculate
the % RSD for the Retention time and Area.
Acceptance criteria
% RSD for Retention
time should be ≤ 0.5 %
% RSD for Area Should be ≤
0.5 %
RSD Formula
RSD = STDED * 100 / Avg
Frequency- Every Six Month
Maintenance
- Check the gas connection, moisture trap condition column connections, any leak in the helium cylinder and change the septa if damaged.
- Run the column conditioning at the end of the sequence.
- After every 50-60 injections the septas are needs to be changed.
- Do bake out the system whenever the vacuum is put down and the moisture is high.
- Clean the liner in every hundred injections depending on the sample matrix analysed.
- Change the wash solvent in the vial daily. Before start of analysis.
- Do a frequent test of gas leakage to avoid any hazard.
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