The phenomenon of choosing or using cuvettes improperly, leading to the inability to measure or causing measurement errors, often occurs in experiments and is easily overlooked by laboratory personnel.

The definition of the ultraviolet (UV) region is 190-400nm, and quartz cuvettes can be used in the range of 190-900nm, while glass cuvettes are suitable for 360-900nm. For the UV region, quartz cuvettes must be used, and it is necessary to configure a UV/Visible spectrophotometer; otherwise, analysis in the low-wavelength range cannot be conducted.

For individuals without an optical background, it may be challenging to visually distinguish between quartz and glass cuvettes. However, the difference in hardness between the two is substantial. Quartz cuvettes have a much higher hardness (absolute value) compared to glass cuvettes, with quartz being tens of times harder. If the two are rubbed against each other, quartz cuvettes will experience minimal wear, while glass cuvettes will wear significantly.

Due to the broad transmittance range of quartz cuvettes from 0.12-4.5 micrometers (120nm-450nm), there is no absorption peak in a wide spectral range. In contrast, glass cuvettes only have a range of 0.4-4 micrometers (400-4000nm) and exhibit many ion absorption peaks. Therefore, quartz cuvettes are superior to glass cuvettes, providing more accurate and reliable analytical data.

It is possible for optical technicians to visually observe the difference in refractive index by hand or with the naked eye. They can accurately determine this based on experience by "comparing the refractive index with the naked eye." However, for individuals without experience, judgment errors are highly likely.

Methods:

Method 1:

• Quartz cuvettes typically have a "Q" marking (quartz), while glass cuvettes have a "G" marking (glass). If the markings are not present, differentiation can be done by testing in the UV range where quartz has higher transmittance.

Method 2:

• Set the spectrophotometer wavelength to 250nm, zero it in the absence of any sample in the sample chamber, place the cuvette on one side of the sample chamber, and if the absorbance is less than 0.07Abs, it is quartz material; otherwise, it is glass material. Note: If the absorbance is slightly greater than 0.07Abs, it may still be quartz material, but the cuvette walls may not have been properly cleaned.