Mastering the safe use of dual beam UV visible spectrophotometers requires systematic management based on instrument characteristics, operating procedures, and potential risks. The following is a detailed safety operation guide:

1、 Preparation and environmental inspection before starting the dual beam UV visible spectrophotometer

1. Electrical safety confirmation

Ensure that the power supply voltage complies with the equipment labeling range (usually allowing ± 10% fluctuation), and is well grounded to avoid the risk of static electricity accumulation or leakage.

Check if there are any signs of damage or aging on the wires, and avoid using the multi way power strip for overload power supply.

For old laboratory circuits, it is recommended to install leakage protection circuit breakers.

2. Environmental adaptability verification

The workbench should be kept level and stable, with sufficient space reserved around for heat dissipation (at least 15cm gap on both sides); Stay away from vibration sources such as centrifuges, air compressors, and other equipment.

Control environmental temperature and humidity: The temperature should be controlled within the range of 15-30 ℃, and the humidity should be below 75% RH to prevent mold growth of optical components; Equipped with dehumidifiers to cope with humid seasons.

Avoid direct sunlight on the instrument panel to prevent the LCD display from fading and becoming ineffective.

3. Principle of sample pre screening

It is prohibited to directly test volatile and corrosive reagents (such as concentrated sulfuric acid and hydrofluoric acid). Sealed colorimetric dishes must be used and protective masks must be worn; Strong oxidizing substances may damage quartz window panels.

Suspended particle samples need to be filtered through a 0.45 μ m filter membrane first to prevent the risk of pressure surge caused by clogging of the flow cell pipeline.

2、 Standardized operation process of dual beam UV visible spectrophotometer

1. Basic setup steps

Standardization of wavelength calibration: After each startup, perform an automatic calibration program and use a standard filter (such as praseodymium neodymium glass) to verify the accuracy of the monochromator, ensuring that the wavelength error is less than ± 0.5nm.

Baseline correction dual channel matching: Place blank reference solution separately in the sample pool and reference pool, and activate the "Baseline Correction" function to eliminate system bias. Note that the optical path difference between the two beams should be less than 0.1%.

Sensitivity gradient test: Measure a series of standard solutions from low concentration to high concentration in sequence. When drawing the working curve, the correlation coefficient R should be above 0.999 before actual sample analysis can be carried out.

2. Taboos for operating precision components

It is strictly prohibited to touch the grating/prism components inside the monochromator with bare hands, as grease stains will reduce diffraction efficiency; When cleaning, only use lens paper dipped in anhydrous ethanol for one-way wiping.

It is forbidden to leave sample residue inside the integrating sphere chamber. After the experiment, it must be cleaned with an ear wash ball, otherwise scattered light interference will cause poor repeatability.

When replacing the deuterium lamp, cotton gloves should be worn to avoid finger marks affecting the ultraviolet transmittance; Before the new light is activated, it needs to be preheated for 30 minutes to stabilize the output.

3. Data processing security boundary

When the absorbance exceeds the upper limit of the measurement range (usually Amax ≤ 2.0), forcibly diluting the sample and retesting may result in detector saturation distortion due to out of range readings.

Manual review should be conducted on data points with abnormal mutations (such as peak signals) to eliminate false positive results caused by bubble interference or electronic noise.