The
procedure for the operation and calibration of the polarimeter. It is the
policy of XYZ Pharmaceuticals Limited that a written procedure shall be
followed for the operation and calibration of the polarimeter.
This
SOP is applicable at the time of the operation and calibration of the
polarimeter.
RESPONSIBILITY AND ACCOUNTABILITY
Persons
along with their responsibilities and accountability are given below:
Executive
- Corporate Quality Assurance:- To prepare the SOP. Maintain the record as per
SOP.
Trainee
Analyst/ Jr. Analyst/ Analyst/ Sr. Analyst:- To follow the SOP accordingly
Manager
- Quality Assurance:- To ensure implementation of SOP.
Operation and Calibration of Polarimeter
Operation of the Polarimeter
5.1.1 Connect the instrument to the main power supply (if not connected).
5.1.2 Ensure that the instrument is clean and free from dust particles.
5.1.3 Ensure that the polarimeter tube is cleaned each time before and after use.
5.1.4 Switch “ON” the instrument and allow sufficient time to achieve the maximum
brightness of the sodium lamp.
5.1.5 Adjust the eyepiece after viewing through it to get a clear focus.
5.1.6 Ensure that the settings are done in the zero-zero position.
5.1.7 Open the polarimeter tube compartment and place the polarimeter tube, which is
filled with a blank solution in such a way as to avoid air bubbles at 25oC.
5.1.8 Close the open end of the polarimeter tube and bring the air bubble (if any)
into the central bulged portion of the tube.
5.1.9 Determine the five readings of blank solution and calculate the average of
blank readings.
5.1.10 The
specific rotation observations are done by viewing through the telescope when
the half dark and half portion of the cycle are in equilibrium.
The
half dark and half light are matched with the knob rotating it in the clockwise
and anticlockwise directions. It is also defined as Dextro (+) or Levo (-)
rotating respectively.
Note
the observation readings.
Now
fill the polarimeter tube with test solution (maintained at 25 ˚C) and
determine the zero point of the polarimeter and then make five readings of the
observed rotation of the test solution.
The
zero correction is the average of the blank readings and is subtracted from the
average observed rotation if the two figures are of the same sign or added if
they are opposite in sign to obtain the corrected observed rotation
5.1.15
In the case of the liquids, adjust the temperature of the substance under
examination to 25 ˚ C unless specified in the monograph, transfer to
a polarimeter tube and proceed as described above.
Switch
“OFF”, clean the instrument and keep it under cover when not in use.
5.1.17
The logbook shall be maintained as per XYZ/CQA/SOP-061/FR-01, Logbook for
Polarimeter (Appendix I).
Calibration of polarimeter as per IP
The
frequency of calibration shall be on a quarterly basis and after the
maintenance of the instrument.
Switch
“ON” the instrument and warm up the sodium lamp to its maximum brightness.
Set
the alignment of the sodium lamp compartment to the optical bench.
Ensure
that all the settings are done in the zero position.
Open
the polarimeter tube compartment and place the polarimeter tube, which is
filled with water in such a way as to avoid air bubbles at 25oC.
The
specific rotation observations are done by viewing through a telescope when the
half dark and half light portions of a circle are in equilibrium.
This
half-dark and a half-light portion are matched with a knob by rotating it in a
clockwise or anti-clockwise direction. It is also defined as Dextro (+) or Levo
(-) rotatory respectively.
Note
the observation readings.
Preparation of Standard Solutions used for calibration polarimeter
5.2.9.1
Dried the sucrose used for calibration for 2 hours in a vacuum oven
(60 ˚C).
5.2.9.2
10 % w/v solution: Weigh accurately about 10 gm of the standard (sucrose)
in a 100 ml volumetric flask, add a sufficient amount of distilled water to
dissolve, and then make up the volume up to the mark with distilled water.
5.2.9.3
20% w/v solution: Weigh accurately about
20 gm of standard (sucrose) in 100 ml volumetric flask, add a sufficient amount
of water to dissolve and then finally make up the volume up to the mark with
distilled water.
5.2.9.4
30 % w/v solution: Weigh accurately about 30 gm of standard (sucrose) in
100 ml volumetric flask, add a sufficient amount of distilled water to dissolve
and then finally make up the volume up to the mark with distilled water.
5.2.9.5
40%w/v solution: Weigh accurately about 40 gm of standard (sucrose) in
100 ml volumetric flask, add a sufficient amount of distilled water to dissolve
and then finally make up the volume up to the mark with distilled water.
5.2.9.5
50 % w/v solution: Weigh accurately
about 50 gm of standard (sucrose) in 100 ml volumetric flask, add a sufficient
amount of distilled water to dissolve, and then finally make up the volume up
to the mark with distilled water.
Now
fill the polarimeter tube with 10% w/v solution of sucrose carry out the
determination in a similar manner as blank at 25oC.
Repeat
the step 5.2.4 to 5.2.8 for 20, 30, 40 and 50% w/v concentration of sucrose
solution.
Clean
the instrument and keep it under cover when not in use.
The
table containing concentration and corresponding angle of rotation in a 2-dm
tube at 25oC is indicated below:
Concentration (gm/100ml) The angle of rotation (+) at 25°C
10.0 13.33 ± 0.05
20.0 26.61 ± 0.05
30.0 39.86 ± 0.05
40.0 53.06 ± 0.05
50.0 66.23 ± 0.05
The
polarimeter is calibrated and plot a graph for linearity and Acceptance
criteria of correlation coefficient should not be less than 0.99.
Record
the observations of the calibration as per XYZ/CQA/SOP-061/FR-02, Calibration
Data Sheet (Appendix II).
Compare
the result with acceptance criteria and take valid calibration authorization
from Manager – Quality Assurance. Affix the calibration sticker on the
instrument as per SOP no. XYZ/CQA/SOP-006, Labelling policy and fill all the
details carefully.
Report
any discrepancy observed during calibration of instrument to Manager Technical
Quality Control or his authorized representative for corrective and preventive
action.
Manager
Technical Quality Control or his authorized representative will report the same
to Manager-Quality Assurance and notify the defect to Engineering Department
service engineer to rectify the defect.
If
the instrument has any discrepancy, affix the ‘Out of Order’ label on the
instrument as per SOP no. XYZ/CQA/SOP-006, Labelling policy.
CALCULATIONS
Calculate
the specific optical rotation using the following formulae, dextrorotation and
laevo - rotation being designated by (+) and (-) respectively.
For
liquids [α] 25D
= α / Ld 25
For
solids [α] 25D
= 100 α / Lc
Where,
α
= corrected observed
rotation, in degrees, at 25˚
D
= D line of sodium light
(L = 589.3 nm)
L
= length of the
polarimeter tube in dm
d2525 =
specific gravity of the liquid or solution at 25 ˚
c
= concentration of the
substance in percent w/v
CLEANING OF POLARIMETER TUBE
Never
use a brush to clean the polarimeter tube.
Clean
the polarimeter tube using the purified water or any organic solvent (acetone
or methanol) and dry the polarimeter tube.
Add
about 1 ml of the solution to be measured. Tilt and turn the polarimeter tube
so that the solution has contact with the entire surface. Discard the solution
and repeat this rinse once more.
5.4.5
Wash the polarimeter knurled rings and glass with the solvent used for the
preparation of the solution for a test. Reassemble the polarimeter tube and
keep it in a closed container.
5.4.6
Wipe the optics with soft tissue paper.
Wipe
the outside of the polarimeter tube with a lint-free, soft tissue to remove any
moisture or fingerprints from the outside surface.
Do
not use acid/alkali solution or solvent for the cleaning of the instrument
PRECAUTION OF POLARIMETER
The
instrument must be in good condition. The optical element must be very clean
and in exact alignment. The match point should be close to the normal zero
mark.
The
light source should be properly aligned with respect to the optical bench. It
should be supplemented by a filtering system capable of isolating the D line
from sodium light.
Specific
attention should be paid to the temperature control of the solution and of the
polarimeter.
Differences
between the initial readings or between observed and corrected optical
rotation, calculated as either specific optical rotation or optical rotation,
should not be more than one-fourth of the range specified in the monograph for
the substance.
Polarimeter
tubes should be filled in such a way as to avoid air bubbles. Particular care
is necessary for semi-micro or micro-tubes.
For
tubes with removable end-plates fitted with gaskets and caps, tighten the endplates only enough to ensure a leak-proof seal between the endplate and body
of the tube.
For
substances with low rotatory power, the end-plates should be loosened and
tightened again after each reading, in the measurement of both the rotatory and
the zero point.
5.5.8 Liquids and solutions of solid must be clear
6.0 GENERATION
OF INSTRUMENT CALIBRATION NUMBER
Generate
the instrument calibration number on the calibration datasheet as INSCALXXYYZZZ
where INS denotes instrument, XX denotes the year, YY denotes month and ZZZ
denotes sequence number.
7.0 ABBREVIATIONS
XYZ
XYZ Pharmaceutical Limited
CQA
Corporate Quality Assurance
SOP
Standard Operating Procedure
