As a novice in the analysis laboratory, it is inevitable to step into some pitfalls when encountering the 759S Edge Light UV Visible spectrophotometer for the first time. Although this instrument plays an important role in the laboratory, improper use can lead to inaccurate data, instrument malfunctions, and many other problems.
After a period of practical exploration, I have summarized some common mistakes and solutions that beginners often make, hoping to help everyone avoid detours.
The Trap of Zero Adjustment and 100% Adjustment
When I first started using 759S, I often encountered the problem of being able to zero normally but unable to adjust 100% when measuring wavelengths below 400nm. Every time it is adjusted to 100%, an error prompt appears, catching people off guard.
After consulting with an experienced mentor, I found out that this is likely caused by insufficient energy of the deuterium lamp. Deuterium lamps are responsible for the light source in the ultraviolet band. When used beyond their lifespan, their energy will decrease, affecting measurements in the ultraviolet region.
Solution: Check the usage time of the deuterium lamp. If it exceeds its service life (usually about 1000 hours), it should be replaced in a timely manner. Be particularly careful when replacing light source bulbs, and follow the instructions as this process involves adjusting circuit connections and optical components.
The invisible killer of the colorimetric dish
Once, the absorbance value I detected was very unstable, fluctuating high and low, which made me suspect that there was a big problem with the instrument. After careful investigation, it was ultimately found that the problem was on the colorimetric dish - there were scratches and stains on the surface of the dish.
Novices often overlook that the cleanliness and integrity of the colorimetric dish directly affect the test results. Even seemingly clean colorimetric dishes can introduce errors if used improperly.
Solution: After each use, rinse the colorimetric dish with purified water in a timely manner, then rinse with methanol or acetone, and gently wipe with specialized lens cleaning paper; Avoid touching transparent surfaces with your hands; Store the colorimetric dish in a dedicated box to prevent scratches.
At the same time, attention should be paid to the pairing of colorimetric dishes - unpaired colorimetric dishes can seriously affect testing accuracy. The original colorimetric dish of the instrument has undergone paired testing and should not be mixed.
The baseline noise is high, and the results fluctuate continuously
In the absence of any items in the sample room, I found that the baseline noise in the ultraviolet region was very high and the readings were unstable. This often means that the instrument needs maintenance.
Possible reasons include: dirt on the optical system mirror, ineffective desiccant, or high environmental humidity.
Solution: Regularly replace the desiccant inside the instrument, at least once every two weeks; Ensure that the instrument is placed in a dry environment; If the problem persists, it may require professional personnel to clean the optical system.
Common Negligence in Instrument Preparation Work
Novices often rush to achieve success and start measuring directly after booting up, but overlook the key preparation work:
-Insufficient preheating time: The instrument needs to be preheated for at least 30 minutes after startup, and the Edge Technology 759S also needs to be preheated before it can work stably. Hastily starting the measurement can cause reading drift and inaccurate data.
-Wavelength setting error: Before each measurement, check if the wavelength is the desired value. Especially when switching between the ultraviolet and visible light regions, attention should be paid to the conversion of the light source.
-Improper blank correction: Incorrect blank solution configuration can make it difficult to adjust to 100%. Ensure that the blank solution is similar to the sample solution matrix and does not affect the test.
Missing points in daily maintenance
The long-term stability of instruments cannot be achieved without daily maintenance. The following are some points that beginners may easily overlook:
-Poor cleaning: Not only should the color dish be cleaned, but the inside of the instrument also needs to be regularly wiped with a clean soft cloth to prevent dust accumulation from affecting the light path.
-Environmental factors: The instrument should be placed in a stable, dry, and dark place, avoiding vibration, moisture, and direct sunlight. At the same time, to ensure stable power supply, it is best to use a regulated power supply.
-Light source lifespan management: Record the usage time of deuterium and tungsten lamps, replace the bulbs according to the prescribed time, and avoid affecting the test results due to bulb aging.
The 759S Edge UV Visible spectrophotometer is indeed a high-performance instrument that can be stably used in various detection tasks as long as it is used correctly, maintained carefully, and repaired in a timely manner.