NanoCuvette™ One offers a quick and easy way to investigate honey quality and moisture content.
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Honey is a natural sweet food substance produced by bees from the sugary segregation of plants, also known as floral nectar. The major component of honey is sugar, primarily glucose and fructose. However, it also contains a wide range of other substances, including proteins, vitamins, minerals, phenol compounds and a small amount of water. The physical properties vary for every honey product depending on water content, type of flora used, temperature and sugar content.
Moisture content is a very important parameter for honey stability. Low moisture content (< 20%) protects the honey from microbial activity and allows it to be preserved for longer periods. For this reason, it is important to have knowledge of water content in the sample during quality control. Moisture content in honey is usually determined based on refractive index measurements. Knowing the refractive index at 20ºC, the percentage of water in a set of honey samples can be calculated using the Wedmore equation.
Traditionally a specialized refractometer has been required for determination of the refractive index. However, with the innovative NanoCuvette™ One, a nanosensor has been developed and implemented in a cuvette, allowing determination of the refractive index to be carried out in a standard spectrophotometer. This way even compounds that do not absorb light in the UV-visible spectrum can be quantified with a conventional spectrophotometer.
This method does not entail any safety precautions. Please refer to common laboratory practices.
- Materials and apparatus
The only apparatus required is a standard spectrophotometer and a computer with internet access. For each measurement a NanoCuvette™ One is required.
- Sample preparation
Seven types of honey having different colors and sugar content have been used. Pure samples with known water content ranging between 16.2% to 18.2% have been used to verify the results
- Measurement procedure
The spectrophotometer and computer are switched on and the free NanoCuvette™ One software is opened. For each sample a new NanoCuvette™ One is used according to the software guidance. Following the last measurement, the software will present the data as a variable of absorbance or refractive index, depending on the experimenter’s preferred choice of representation (Figure 1).
- Giulio Sesta, Lorenzo Lusco. Refractometric determination of water content in royal jelly. Apidologie, Springer Verlag, 2008, 39 (2), pp.225-232. <hal-00892298>
Figure 2. NanoCuvetteTM One measures refractive index and absorbance on the same sample, using only a standard spectrophotometer and the free NanoCuvetteTM One software.