Calibration of Semi-micro Osmometer, Purpose:
Calibration of Semi-micro Osmometer, The purpose of this SOP is to describe the operation, calibration and cleaning of Semi-micro Osmometer (Brand: KNAUER; Model: K-7400) used in the quality control laboratory of XX Pharmaceuticals Limited.
Calibration of Semi-micro Osmometer,Scope:
This procedure is applicable for Semi-micro Osmometer, installed in the quality control laboratory general block of Labaid Pharmaceuticals Limited.
Definitions / Abbreviation:
Standard Operating Procedure (SOP): Standard Operating Procedure.
QC: Quality Control.
Responsibilities:
The roles and responsibility is as follows:
Sr. Executive/Executive, QC
[][]To ensure that this procedure is followed.
[][]To maintain the records properly as per SOP.
Manager, Quality Control
[][]To ensure that this procedure is kept up to date.
[][]To confirm that the SOP is technically sound and reflects the required working practices.
[][]To arrange training on the SOP to all concerned personnel and to ensure implementation of the SOP after training.
[][]Schedule calibration of the instrument at the defined intervals.
Head of Quality Assurance
Approval of the SOP.
To ensure the overall implementation of the SOP.
Procedure:
Precaution(s):
[][]Prior to use, user must ensure that equipment is calibrated.
[][]To ensure a fixed sample volume, always introduce the solutions with a clean and dry pipette into the measuring vessel.
[][]Handle the thermistor always very carefully. All abrasive materials should be kept away from it.
[][]Solutions containing proteins, such as sera, can only be measured once. Freezing causes denaturisation of the protein so that repetition of the measurement with the same sample would result in increased values. Thus, in the case of sera, only one measurement is possible for one sample.
[][]Only real osmolalities can be measured. It is not possible to prepare other standard solutions by dilution of a calibration solution since the activity coefficient of the solution changes with dilution.
[][]In this case Store the water which is used for the zero point calibration in glass bottles.
[][]If the same salt solution is measured several times, it must be mixed after thawing (stir briefly). During the thawing process ice floats to the top of the solution. As ice does not contain salt, the top layer of the solution is diluted while thawing.
[][]Calibration solutions can become more concentrated if the bottle is opened frequently. So, use KNAUER calibration solutions in glass ampoules.
[][]Prior to the measuring, a little bit water condensed in the cooling compartment should be removed with a dry cloth.
Operation:
[][]Preparing the Osmometer K-7400
[][]Switch ON the instrument at least 5 minutes before use.
[][]Press the vibrator key to check the stirrer. It will run for a second.
[][]Optionally a thermo printer can be connected to the RS232 socket. The result of each measurement will be printed automatically.
[][]After a calibration, an outprint of Calibration will be found automatically.
[][]In case of interrupted runs (caused by any error), the screen displays the corresponding error message.
Preparing a Measurement
[][]Place 0.15 ml sample or calibration solution into a clean, dry measurement vial.
[][]Put the vial all the way into the adapter. The meniscus of the liquid must be horizontal.
[][]Place the measuring head on the instrument in such a way that the vial extends into the cooling cavity.
[][]Thus the instrument is ready for calibrating or measuring.
Calibration:
[][]Prepare the instrument for a measurement of deionised water.
[][]Set the first field in the second row of the CALIBRATE screen to „0000“.
[][]Press the start key.
[][]After finishing the run on the screen is displayed 0000 mOsmol > -0.81°C<.
[][]To accept this value, press the START key again.
[][]Wait for the warming up to the stand-by temperature.
[][]Prepare the instrument for a measurement of a 300 mOsm/kg calibration solution.
[][]Activate the second calibration field and select “0300” and repeat steps
[][]For a 4 point calibration, repeat the procedure for calibration fields
Measuring Samples:
[][]Prepare the instrument for a measurement of a sample solution.
[][]Press the START key to start the measurement run.
[][]The instrument detects the freezing point depression and if the crystallisation occurred properly displays the corresponding osmolality on the main screen.
[][]The printer output is given automatically.
[][]If no crystallisation (temperature increase) takes place after the automatically start of the vibrator the measurement will be stopped with the error message “> ERROR < NO FREEZE”.
[][]If the crystallisation (temperature increase) takes place before the start of the vibrator the measurement also will be stopped with an error message> ERROR < FREEZE.
[][]Do not remove the measurement vessel from the adapter before the sample is molten. Otherwise the danger of damaging the measuring head is given. The sample melting can be accelerated by warming up with the fingers.
Cleaning procedure:
[][]Measuring vessel and thermistor should be cleaned occasionally with KNAUER cleaning solution supplied with the instrument. (Dilution: 1: 10 solution in purified water of 40±5°C)
[][]Clean and dry the measuring vessels with alcohol or acetone because remaining solvent vapours could cause false results.
Annexure:
Annexure-I: Operation Logbook for Semi-micro Osmometer.