1、 Preparation before use

1. environmental control
   • Temperature and humidityThe laboratory temperature should be stable at 20-25 ° C, and the relative humidity should not exceed 70%. If used outdoors, avoid direct sunlight and use insulation sleeves or other equipment to maintain temperature stability.
   • Clean the countertopThe experimental table should be kept clean and tidy to avoid dust or impurities interfering with the purity of the sample or reagent.
2. Instrument preheating and calibration
   • preheatPreheat the internal components for 15-30 minutes before starting up to reach a stable state.
   • calibrationUse distilled water or standard samples to calibrate readings and ensure zero point accuracy. For Abbe digital refractometers, a circulating constant temperature water bath can be equipped to maintain a constant temperature.
3. Sample processing
   • centrifugal separationIf the sample contains cell debris or other particles, it needs to be centrifuged first, and the supernatant should be taken as the test sample to reduce non-specific binding.
   • Dilution adjustmentIf the sample concentration is too high and exceeds the detection range, it needs to be diluted appropriately (usually recommended dilution ratio of 1:10 to 1:100).
   • uniformly mixedThe sample needs to be centrifuged at low speed or thoroughly stirred before measurement to ensure uniform mixing.

2、 Operating standards

1. Correct grip and operation
   • Gripping methodWhen using a refractometer, hold the rubber sleeve with four fingers of your left hand and adjust the eyepiece with your right hand to prevent body temperature from entering the instrument and affecting measurement accuracy.
   • Sample addition sequenceFollow the sequence of adding standard samples from low concentration to high concentration into the microplate, and finally add the test sample to reduce the risk of cross contamination.
   • Micro pipettingWhen using a micropipette, gently and evenly aspirate and release the liquid to avoid the formation of bubbles that may affect the absorbance or fluorescence signal.
2. Light path and mirror cleaning
   • clean the mirrorGently wipe the rough surface of the entrance prism, the polished surface of the refractive prism, and the polished surface of the standard sample with a mixture of liquid and defatted cotton to ensure cleanliness.
   • Avoid scratchesWhen scrubbing, use a soft cloth or paper to avoid scratching the mirror or drip port glass.
3. Wavelength and time settings
   • Wavelength selectionSet appropriate excitation and emission wavelengths according to the detection method (e.g. 595nm is usually selected as the detection wavelength when determining protein concentration using the Bradford method).
   • Time programSet appropriate incubation time and reading intervals to ensure that the reaction proceeds fully while capturing dynamic changes.

3、 Post use maintenance

1. Timely cleaning
   • Clean the drip portAfter measuring a sample each time, clean and dry the drip port to avoid residual corrosive substances.
   • Clean the probeAfter the measurement is completed, clean the probe with distilled water, soak it for 30 seconds, and then dry it to prevent sample residue or corrosion.
2. Properly stored
   • Storage environmentThe instrument should be stored in a dry, dust-free, oil-free, and acid free place to avoid corrosion or mold growth of optical components.
   • dust coverAfter use, cover the instrument with a dust cover to prevent dust from entering.
3. regular maintenance
   • Check the light sourceRegularly inspect the light source for damage or aging, and replace it with a new one if necessary.
   • Calibration instrumentRegularly calibrate the instrument according to its usage level to ensure stable performance.

4、 Special sample processing

1. Corrosive liquid
   • When testing corrosive liquids, it is necessary to clean optical parts, metal parts, and paint surfaces in a timely manner to prevent erosion and damage.
   • Try to avoid touching any part of the instrument with your hands to prevent corrosion.
2. Hard block material
   • There should be no hard lumps in the tested sample to avoid scratching the mirror surface and affecting measurement accuracy.

5、 Safety precautions

1. Avoid severe vibrations
   • The instrument should be handled with care during use and maintenance to avoid collisions, strong vibrations, or impacts, and to prevent damage to optical components or mechanical structures.
2. Prevent electrical faults
   • If the non rotation of the reflector is caused by an electrical fault, the control circuit should be checked and repaired to avoid further damage to the instrument.
3. Power supply and grounding
   • Check if the power supply is connected properly, ensuring that the power plug is securely plugged in and the power cord is not damaged.
   • Check if the grounding is good, ensure that the grounding wire is firmly connected, and prevent electrical safety hazards.