Welcome to Qinsun Instruments Co., Limited.
2023-05-23 0 Views

Principle of the visible spectrophotometer

A double-beam UV-Vis spectrophotometer (hereafter referred to as an instrument) is a device in which the monochromatic light emitted by the monochromator is split into two beam structures of sample and reference by a beam switch (chopper). ). Instrument. DYQTextile Testing Instruments, Testing Equipment Manufacturer


It can eliminate the influence of light source instability and amplifier gain fluctuations, and automatically record and scan the absorption spectrum of the substance. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Normally the device performs some self-tests after start-up, but it should still be calibrated according to this regulation. The wavelength range of the instrument is 195-800 nm and the slit is adjustable from 0.1-5 nm. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Principle of operationDYQTextile Testing Instruments, Testing Equipment Manufacturer


UV-visible spectrophotometry is an instrumental analysis that utilizes the absorption of radiation in the ultraviolet-visible spectral range by material molecules. DYQTextile Testing Instruments, Testing Equipment Manufacturer


This Art of molecular absorption spectrum arises from the transition of energy level of valence electrons and is widely used in qualitative and quantitative analysis of inorganic and organic substances. DYQTextile Testing Instruments, Testing Equipment Manufacturer


The Lambert-Beer law (Lambet-Beer) is the fundamental law of light absorption, commonly known as the law of light absorption, and is the basis and basis for quantitative analysis by spectrophotometry. DYQTextile Testing Instruments, Testing Equipment Manufacturer


If the wavelength of the incident light is constant, the absorption of the solution is a function of the concentration c of the light-absorbing substance and the thickness of the absorbing medium (absorption path). DYQTextile Testing Instruments, Testing Equipment Manufacturer


The usual expression is as follows (where ε is a coefficient):DYQTextile Testing Instruments, Testing Equipment Manufacturer


A=ε c lDYQTextile Testing Instruments, Testing Equipment Manufacturer

Ultraviolet-visible spectrophotometer is a conventional analytical instrument based on the principle of ultraviolet-visible spectrophotometry. Depending on the design of the beam path, UV-Vis-Spectrophotometer can be divided into single-beam spectrophotometer, double-beam spectrophotometer and dual-wavelength spectrophotometer. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Basis for FormulationDYQTextile Testing Instruments, Testing Equipment Manufacturer


This procedure relates primarily to the National Metrology Verification Regulations “JJG178-2007 Ultraviolet, Visible, and Near-infrared Spectrophotometers ', 'JJF1641 - The Outline for Type Evaluation of UV-Vis Spectrophotometers 2017 and the 2015 Edition of the Four Guidance General Rules 0401 UV-Vis Spectrophotometry of the Chinese Pharmacopoeia have been prepared. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Elements and technical requirementsDYQTextile Testing Instruments, Testing Equipment Manufacturer


Wavelength accuracy ≤±1.0 nm (ultraviolet range), ≤±2.0 nm (near 500 nm); DYQTextile Testing Instruments, Testing Equipment Manufacturer


p>


Wavelength repeatability ≤0.5 nm. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Baseline straightness ≤ 0.01 absorbance. DYQTextile Testing Instruments, Testing Equipment Manufacturer


0% line noise ≤ 0.1%, 100% line noise ≤ 0.5%.DYQTextile Testing Instruments, Testing Equipment Manufacturer


The absorption accuracy should meet the requirements. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Stless than 0.8%. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Spectral bandwidth ≤ marked bandwidth ± 20%. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Absorption Cell Agreement Error ≤0.5%. DYQTextile Testing Instruments, Testing Equipment Manufacturer


Test result processingDYQTextile Testing Instruments, Testing Equipment Manufacturer


If all self-test results meet the technical requirements, it is qualified and can be used. If the test result does not meet the requirements, the device should be recalibrated and then subjected to a self-test. It can only be used if it complies with the regulations. DYQTextile Testing Instruments, Testing Equipment Manufacturer

DYQTextile Testing Instruments, Testing Equipment Manufacturer