Pollen scanner

Published: Saturday 31 January 2009

-- (Credit: MEETA AHLAWAT)For effective advisories, an accurate pollen count

POLLEN grains inspire botanists the same way snowflakes inspire poets. These intricately structured entities also cause hay fever and make thousands sneeze during the flowering season. Health authorities usually bring out advisories to caution allergic people when the culprit plants are in bloom. But finding out when the pollen count is high so that the advisories can be brought out requires proper identification of the pollen first.

Pollens are complex structures and consist of a variety of molecules from extremely stable biopolymers of unknown composition and structure to pigments such as flavonoids and carotenoids and structural components like lignin and pectin. The chemicals present on the surface of the pollen are the ones that cause allergies.

The conventional method of checking for the presence of pollen in the air is by using a microscope. This is a slow and cumbersome process and needs an expert who can see and identify the pollen. Identification through chemical analysis is not always possible as the pollen samples require lengthy processing.

A group of researchers in Germany has developed an automated technology to counter these problems. They have used a procedure called Raman spectroscopy to analyze the chemicals present on the pollen's surface. To demonstrate its efficacy, they fed the chemical 'signatures' for 15 different kinds of tree pollen into the instrument.

The instrument is expected to scan pollen grains in the air and match them with the signatures. As the signature is simply a superimposition of the chemical nature of different pollen components, the technique can identify the pollen even when broken bits of it are in the air.

The advantage of using Raman spectroscopy is that it does not require processing of the sample. Moreover, it requires very small amounts of material and the process itself takes very little time. The study has been published in the recent issue of Analytical Chemistry (Vol 80, issue 24).

This research will make it easier to bring out advisories which will warn allergic people to stay indoors when the pollen count is high. However, this cannot take care of the problem completely as it is not easy to evade the millions of pollens released by each flower. Moreover, pollens are airborne. They are mainly dispersed by the wind from far flung areas which makes them all pervasive.

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