Visible Spectrophotometer Operation Application Instructions

Visible Spectrophotometer is an instrument and equipment used to detect and track the absorbance of the measured substance to visible light and perform quantitative analysis.

working principle

Under the excitation of visible light, the substances in the solution produce the effect of light absorption, and this absorption is selective. Various substances have their own absorption spectra, so when a monochromatic light passes through the solution, its energy will be absorbed and weakened. One Beer's Law (see Figure 3-10).

When the optical path length of the liquid is constant, the transmitted light changes according to the concentration of the solution. The basic principle of the visible Spectrophotometer is designed according to the above physical optical phenomenon.

The structure of the instrument

There are many types and models of visible Spectrophotometer s. The 72 and 722 visible Spectrophotometer s commonly used in experimental chemistry are briefly introduced as follows.

The structure of the 1.72 type Spectrophotometer

The 72-type Spectrophotometer is composed of three parts: a magnetic saturation voltage regulator, a monochromator and a galvanometer. When in use, these three parts should be connected with wires according to Figure 3-11.

Connect the monochromator to the output terminal 5.5V or 10V of the voltage regulator, and then connect the monochromator to the galvanometer according to the color of the bushing on the conductive sheet, and connect the conductive sheet of the red bushing to the "ten" , the conductive piece of the green sleeve is connected to the "one" place, and the third conductive piece is grounded. The voltage stabilizer and the galvanometer are respectively connected to the 220V power supply.

Structure of 2.722 light booth-Spectrophotometer

Model 722 grating Spectrophotometer adopts self-aligning dispersion system and single-beam structure. The dispersion element is diffraction grating. It can also directly measure the concentration of the solution by using digital display readings with a wavelength of 330~800nm. Its shape is shown in Figure 3-12.

Instrument use

How to use the 1.72 type Spectrophotometer

(1) Before turning on the power, the power switches of the voltage stabilizer, galvanometer and monochromator should be in the "off" position. Turn the light quantity regulator counterclockwise to the minimum position, turn the monochromator light gate to the black point, and then connect the voltage stabilizer and galvanometer to the 220V AC power supply.

(2) Turn on the power switch of the galvanometer, turn the gear switch from "OFF" to "Direct" or "X1", and indicate that the light spot appears on the scale, and use the zero adjuster to accurately adjust the cursor line to the transparent On the "0" point of the photometric scale.

(3) Turn on the power switch of the voltage stabilizer and monochromator, turn the light gate to the "red" point, and then rotate the light adjuster clockwise, so that the indicator line of the galvanometer reaches the light transmittance on the scale Near 100%, after warming up for 10 minutes, wait until the cursor is stable before starting to use it. (4) Adjust the wavelength adjuster to the desired wavelength.

(5)将单色器的光闸门拨到“黑”点处,再一次核对检流计零位(即透光度为“0”处)。

(6)将盛空白溶液的比色皿放人比色皿架第一格中,其余=格放入待测溶液,盖上暗箱盖,将空白溶液推入光路(拉杆推到底)。把光闸门拨到“红”点上,轻轻调节光量调节器,把光标线准确地调至透光度“100”的读数上。

(7)把拉杆抽出一格,使有色溶液进入光路,光标线所指的A值就是该溶液的吸光度,再依次测定其他溶液。

(8)测定完毕,取出比色皿把溶液倒掉,用蒸馏水冲洗干净,吸干,放回比色皿盒子内。全部旋钮和开关恢复到使用前的状态,切断电源,把仪器罩好。

注意:

1)在接通电源之前,应检查各个调节旋'题是否均在起始位置,然后再打开电源开关。仪器停止工作时,需要把开关放在“关”上再切断电源。

2)只要空白溶液的透光度能调到“100”,单色器的电源电压应用5.5V,不用10V。这主要是延长光源灯的寿命,降低单色器的温度。

3)检流计背面有两个电源插孔,分别标有“220V”和“6V”。若用220V交流电源,则导线插头应橋入“220V”孔内,者用6V直流电源,则导线插头应插入“6V”孔内,不能插错。否则将把仪器烧坏。

4)在仪器使用过程中,应注意保护光电池,選免长时·间照射而疲劳。当取换溶液和记录读数后.应及时将光闻门拔到“黑”点,切断入射光。

5)应注意保护比色皿的透光面的光洁。使用时只能用手拿毛玻璃面,勿拿透光面。據拭整外溶液时只能用镜头纸。

6)比色皿盛放溶液不能超过其高度的4/5,以免溶液溢入机件内部。

2.722型光柵分光光度计使用方法

(1)在接通电源前,应对仪器的安全性进行检査,电源线接线应牢固,接地线通地要良好,各个调节旋钮的起始位置应该正确,然后再接通电源。

(2)将灵敏度派或调至“1”挡(放6倍率最小)。调波长调节器至所需波长。

(3)开启电源开关,指示灯亮,选择开关置于''T”,调节透光度''100%”旋钮,使数字显示100.0”左右,预热20min。

(4) Open the cover of the absorbing darkroom (the light door is automatically closed), adjust the "0" knob to make the number display "00.0", cover the absorbing cover, place the reference solution in the light path, let the photocell receive light, and adjust the transmittance. Luminosity "100%" knob, make the number display as "100.0".

(5) If the display is less than "100", you can increase the sensitivity level of the current amplifier appropriately, but you should use as low a level as possible, so that the instrument will have higher stability. After changing the sensitivity, you need to press "0" and "100" to recalibrate.

(6) After adjusting "00.0" and "100" several times by pressing (4), set the selector switch to "A", and adjust the absorbance zero adjustment knob to make the number display as ".000". Then push the solution to be tested into the optical path, and the displayed value is the absorbance value A of the sample to be tested.

(7) Measurement of concentration c. Turn the selector switch from "A" to "C", push the standard solution into the light path, and adjust the concentration knob. Make the digital display value the value of known standard solution concentration. Push the sample crystal solution to be tested into the optical path, and the concentration value of the sample to be tested can be read out.

(8) If the test wavelength is greatly changed, wait for a while after adjusting "00.0" and "100" (due to the sharp change of light energy, the photoelectric cell responds slowly after receiving light, and it takes a period of light response balance time), when it is stable, Readjust "00·0" and "100" to work.

Notice:

1) Before use, the user should first understand the structure and principle of the instrument, as well as the functions of each knob.

2) The instrument must be well grounded, otherwise the displayed numbers will be unstable.

3) There is a dry operating agent tube in the lower left corner of the instrument, which should be kept dry. If the dry operating agent changes color, it should be replaced immediately or dried before use.

4) When the instrument stops working, cut off the power supply, switch off the power switch at the same time, and close the instrument.

The above is the author's introduction to the working principle, structural appearance and use method of the visible Spectrophotometer , hoping to provide some references for relevant trial personnel in the industry.