Dualex is a leafclip sensor which measures chlorophyll and polyphenols content of plant leaves.

Thanks to a patented technology this optical sensor allows simple, fast and non-destructive measurement of chlorophyll, flavonols and anthocyanins in leaves.

Chlorophyll meter

Accurate measurement of chlorophyll

Chlorophyll plays a vital role in photosynthesis and plant development.

Dualex measures the chlorophyll by analyzing the light transmitted through the leaf.

Thanks to a chemical calibration made by FORCE-A, the chlorophyll is given in µg/cm² in the range of 5-80 µg/cm².

Flavonols and anthocyanins meter

Unique leafclip sensor to measure flavonols and anthocyanins content in leaves

Flavonols are mainly synthetized after light exposure. As a consequence they are a good indicator of plant-light interaction history.

Dualex measures flavonols and anthocyanins by analyzing the screening effect of flavonols and anthocyanins on chlorophyll fluorescence.

Flavonols and anthocyanins content are given in relative absorbance units from 0 to 3 for flavonols and 0 to 1.5 for anthocyanins.

Nitrogen status indicator

NBI® : Nitrogen Balanced Index

Chlorophyll is often used as an indicator of plant nitrogen status. Several years of research and experimentation showed that polyphenols, specifically flavonols, are also good indicator of nitrogen status of plants.

In one hand, when a plant is under optimal conditions, it favours its primary metabolism. As a result, the plant synthesizes proteins (nitrogen-containing molecules) containing chlorophyll, and few flavonols (carbon-based secondary compounds). In the other hand, in case of nitrogen deficiency, the plant directs its metabolism towards an increased production of flavonols.

NBI® (Nitrogen Balance Index) combines chlorophyll and flavonols (related to nitrogen/Carbon allocation). It’s an nitrogen plant status indicator directly correlated with massic nitrogen content. The NBI® is less sensitive to the variations of environmental conditions than the chlorophyll (leaf age, leaf thickness…).


Non-destructive measurement 

Clipping the leaf with Dualex doesn’t cause any damage.

Fast and simple

One measurement takes less than 1 second.

Dualex measures automatically after leaf detection.

Lightweight and compact

The Dualex is very light (only 220 g, battery included) and compact (it fits into the hand),


Dualex has a wide sampling area. The measurement area is 5mm diameter.

The 8 cm long clip allows to measure the middle of the leaf where chlorophyll is less variable and more representative.

Adapted to experimentation

Dualex offers the possibilities to remove the last measurement and sort data on 2 levels. It also records additional information such as date, time and GPS position.

Dualex is not sensitive to ambient light so you can use it in lab, in greenhouse or in the field.

Principle of measurement

Chlorophyll measurement :

Dualex measures the chlorophyll content of leaf thanks to a transmittance ratio at two different wavelengths.

Dualex measures the transmitted light in the far-red (5) absorbed by chlorophyll. On the other hand, it measures the transmitted light in the near-infrared (6) as reference.

Flavonols and anthocyanins measurement :

Near-infrared chlorophyll fluorescence is measured under a first reference excitation light not absorbed by polyphenols (1) .

Then, a second sampling specific light absorbed by polyphenols (e.g. green (3) for anthocyanins or UV (4) for flavonols) is sent.
But, only a fraction of this light reaches the chlorophyll in the mesophyll. Then, this light generates near-infrared chlorophyll fluorescence (2).

Dualex measures flavonols and anthocyanins content of the leaves epidermis thanks to a differential ratio of chlorophyll fluorescence.

This principle of measurement is called the screening effect of polyphenols on chlorophyll fluorescence.


Dualex is mainly used in Plant Sciences research (physiology, agronomy, ecology, …). For example, Dualex is used for abiotic stress studies (light, nitrogen, temperature, salinity…).

Learn more about Dualex applications on the link below.