1. Calibration
Pradeep Kumar. G.T

2. Definition
Calibration is the set of operations that
establish, under specified conditions,
the relationship between values
indicated by a measuring instrument,
a measuring system or values
represented by a material measure,
and the corresponding known
values/standard value of a
measurand.

3. Steps
1. Identify instruments/glassware
2. Identify sources of calibration
facility/procedures
3. Calibration procedure
4. Documentation
5. sources of error
6. correction

4. 1. Identify instruments/glassware
• Instruments /glassware which
–Directly influence the results
–Measure physical quantities
–Detect the residue
–Used for CRM preparation
–Used for reconstitution

5. 2. Identify sources of calibration
facility/procedures
• Calibration procedures
• IS, ASTM, BS
• Manufacture’s
instruction
•GC, GC-MS, LC-MS

6. • NABL accredited calibration
laboratories
•SCTIMST, Poojappura,
Trivandrum
•STIC, CUSAT, Cochin
•FCRI, Palakkad

7. 3. Calibration procedure
• General rules
• One-point calibration
• Volumetric glassware
• Two-point calibration
• pH meter
• Multi-point calibration
• GC,GC-MS, LC-MS

8. CRMs/Standards for
calibration
• Certified Reference Material
• Certificate
• Correction in the reading
• Calibration Curves
• graph which relates reference
value to the instrument’s output

9. Documentation
• Name of equipment and identification
number
• Observed reading/value
• Reference value
• Difference between reference value
and observed value
• Corrective action may include
servicing, labeling, or disposal

10. Sources of error
• Stabilisation
• Normal position
• Avoid sources of interference
• Avoid traces of leftover
• Calibration accuracy should be 3
to 10 times the accuracy required
for the measurement .

11. Traceability
• Traceable to a national
standards.
• In India it is with National
Physical Laboratories, New Delhi
• SI system

12. Uncertainty

13. Calibration of balance
• Stabilization
• Accuracy test
• Repeatability test
• Eccentricity or off-centre loading
• Acceptance criteria

14. Calibration of GC, LC
• Calibration of Instrument
performance
–Flow calibration using flow meter
–Temperature calibration
–Detector signal/sensitivity
–Mass calibration for mass
spectrometer

15. • External/Internal calibration
using CRMs
– Find out the retention time. (RT,
compound parameters and spectrum
for MS)
– Prepare the pesticide CRM
mixture (min 5 levels)
– Inject this mixture in GC or LC
» Cont.

16. –Give the names, retention
time, compound parameters
and concentration
–Draw the calibration curves.
–This calibration curve can be
used for the quantitation of
pesticides.