The fundamental concept behind how micro spectrophotometer work is that the absorption of substances by light (or the wavelength of light) is selective. Since different substances each have their own unique absorption light band, the spectral analysis that is performed on a solution takes into account which wavelengths of light in the spectrum are going to be absorbed by the solution after the spectrum has been passed through the solution. Beer's law states that there is a proportional relationship between the concentration of the substance in a solution and the amount of light energy that is lost at a given wavelength. This relationship holds true in accordance with Beer's law.
Spectrophotometers come in a wide variety of types, but the most common ones fall into one of three categories: a simple type, a mid-range type, or a type. When selecting a spectrophotometer, Freeze dryer (find a good store) is necessary for us to take into account the following factors.
1. wavelength detection range and wavelength selection mode: the wider the wavelength detection range of the instrument, of course, the higher the price also is; the user needs to choose the appropriate wavelength range according to their needs; for simple type of instrument, wavelength selection mode is generally manual find; the repeatability of this way is poor; type of instrument in the wavelength can be automatically found or scanned in accordance with the set mode, followed by 1. wavelength detection range 1. wavelength detection range 1. wavelength detection range 1. wavelength detection range 1. wavelength detection range 1. wavelength detection range
Beam: Single-beam, dual-beam, and quasi-dual-beam types are the three categories that make up the beam type category. Single-beam spectroscopy is typically appropriate for measuring absorbance at a specific wavelength, but freeze dryer is not possible to perform a full-band spectral scan and freeze dryer calls for an exceptionally stable light source and detector. Double-beam spectroscopy, on the other hand, enables automatic recording and a rapid full-band scan. Pseudo-double beam, also known as proportional double beam, has the advantage of monitoring the error caused by light source changes, and its principle is that the light from the same monochromator is divided into two beams, one beam reaches the detector directly, and the other beam reaches the other detector after passing through the first detector. This method is particularly well-suited for structural analysis because it can eliminate the influence of an unstable light source, detector sensitivity changes, and other factors. It is also known as proportionalHowever, this strategy does not get rid of the influence that is brought on by the reference ratio.
3. Light source: the visible area is lit primarily by tungsten lamps and tungsten halogen lamps (320 nm to 2500 nm); the ultraviolet area is lit primarily by hydrogen lamps and deuterium lamps (180 nm to 375 nm); a xenon lamp can be used as a light source in both the visible and ultraviolet areas.
4. sample holder: simple sample holder for the push-pull quadruple pool holder, where only one sample can be measured at a time, the reference and sample in two measurements; type of cuvette holder for two fixed, respectively, the sample opinion and reference opinion, where you can measure the absorbance value of the reference and sample at the same time.
Slit: The slit of the simple type is typically in a mode of fixed width, and the width of the slit is typically 2 nm, but it can also be 1.5 nm. The slits of the instruments of the type, on the other hand, can be continuously adjusted so that they can conform to the requirements of high resolution.
6. Indicators of optical performance High and low optical performance have a direct impact on the accuracy of the measurement; the grating technical indicators are particularly important in this regard. Type instrument grating quality is superior, generally speaking zui best grating for the concave type, and the larger the size of the concave grating corresponds to the number of grooves, which means that the resolution and stray light indicators are better than the simple type instrument.
7. detector: a detector is a device that makes use of the photoelectric effect, in which the light signal is passed through a solution and then converted into an electrical signal. An electrical signal amplification device is also used. Photosensitive diodes are typically used in simple type instruments; silicon photodiodes are utilized in mid-range type instruments; and type instrument detectors typically make use of high sensitivity photomultiplier tubes and infrared detectors.
8. Display: simple type instruments are typically mechanical meter heads or digital tube displays, and they do not have a data processor; type instrument displays are typically of the liquid crystal variety or are connected to a computer, and data processing can either be done by the instrument itself or by an external computer.
9. measurement mode: simple type instruments are mostly fixed-point (fixed wavelength) absorbance or transmittance measurement, and they essentially cannot be wavelength scanning measurement; type instruments have more measurement modes, and they can display transmittance, absorbance, concentration direct reading, single beam, single point, and scanning, among other measurement options.
10. measurement accessories: when evaluating the quality of an instrument, one essential factor to consider is whether or not the instrument comes with a comprehensive collection of accessory measurement devices. Some examples of these types of devices include polarization accessories, integrating sphere accessories, reflection accessories, autosampler accessories, chromaticity analysis software, and film accessories.
11. Measuring the state of the sample: visible and ultraviolet spectrophotometers are generally used to measure liquid samples, whereas infrared spectrophotometers can generally analyze various states (gas, liquid, and solid) of the specimen.
The qualitative and quantitative analysis of a substance can be performed with the help of a spectrophotometer. This device works by measuring the amount of light absorbed by the substance being measured at a particular wavelength or within a particular wavelength range.
