The spectrophotometer is a device used in the laboratory to determine the concentration of a substance in a solution, thus allowing quantitative analyzes. Proper calibration of the spectrophotometer is a key factor for accurate and reliable measurement.
We must bear in mind that having the spectrophotometer calibrated at all times will help us to obtain much more accurate information about the measurement we make. In addition, in some cases, the device itself may not allow a measurement if it is not pre-calibrated.
We must also bear in mind that the spectrophotometer, being a photosensitive device, can be decalibrated due to abrupt changes in ambient temperature or extreme temperatures.
The calibration process, according to instructions for use, must be performed at most every 14 days. Our recommendation is to do it daily, since the investment of time in relation to its benefits in minimum.
What is the calibration of a spectrophotometer?
Spectrophotometer calibration consists of performing a set of operations that aims to determine the magnitude of errors made by the equipment when making the measurements. These errors are obtained by comparing the results of each measurement with certified values of a reference material, taking into account that the measurements were made under the same or similar environmental conditions and place of calibration.
The calibration takes into account the error quantification and uncertainty of the photometric scale and wavelength scale. These are the basis for knowing the state of your computer with respect to the manufacturer’s specifications, accuracy class, or the equipment’s MPEs. Uncertainties in wavelength and photometric scales are obtained with reference pattern uncertainties.
Key concepts in calibration
Control of wavelength accuracy: This test determines whether the wavelength indicated by the equipment corresponds exactly to that projected.
Photometric accuracy control: this experience establishes the concordance between the absorbance referred to a known solution and the absorbance determined by the equipment.
Photometric accuracy control: this test checks the reproducibility of the measurements made by the equipment to a stable solution.
Photometric linearity control: this property allows to know the range of absorbances within which the spectrophotometer produces responses proportional to the changes in concentration of a substance.
What considerations should you consider when maintaining a spectrophotometer?
Spectrophotometers, in general, are highly specialized and expensive equipment. Its preservation depends to a large extent on the way it is installed and used. The environment around them and the quality of electricity services are of paramount importance, so that the equipment can provide the services according to the specifications for which they were manufactured. The maintenance routines that may be required vary in complexity, ranging from careful cleaning of components to specialized procedures, which should only be performed by technicians or engineers who have received the corresponding training and have the technical information developed by the manufacturers.
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