New sensor can detect eternal chemicals in water quickly and easily (Shutterstock)

Scientists at the British University of Birmingham, in cooperation with the German Federal Institute for Materials Research and Testing, have created an optical sensor to detect “forever chemicals” (PFAS) in water.

PFAS stands for per- and polyfluoroalkyl compounds, a group of chemicals that are widely used in various industrial and consumer products, such as non-stick cookware, waterproof outdoor equipment, food packaging, and firefighting foam. .

These materials have strong chemical bonds that make them resistant to water and grease, which has given them a dominant presence in many products. However, this advantage is a double-edged sword, as on the other hand, it gives these materials extreme stability in the environment and does not decompose easily, and they can remain in the air and water. And soil and living organisms for a very long time, which is why they are called "eternal chemicals."

Studies have linked exposure to some of these substances to harmful health effects, including growth problems, immune system dysfunction, and an increased risk of developing some types of cancer. Therefore, efforts are being made around the world to find tools to detect them in water to prevent one of the ways they are transmitted to the body, causing these diseases. Side effects. The optical sensor, which was reported in the journal Analytical Chemistry, is part of these efforts.

Environmental pollutants may affect the sensitivity and selectivity of analytical tools, leading to challenges in distinguishing between PFAS and other substances (Shutterstock)

Challenges that created the need for a new solution

Over the past years, several different scientific and analytical methods have been used to detect these substances in environmental samples. However, the complex nature of PFAS substances and their widespread use pose challenges in accurately detecting and measuring them quantitatively. These methods include:

  • Analytical methods:

Traditional analytical methods such as gas chromatography and liquid chromatography have been used, but the diversity of PFAS and their varying chemical properties has made it difficult to develop a single method that can detect effectively.

  • Target analysis:

Some attempts have focused on specific PFAS compounds, often those that are the most well-known or have known industrial uses, and this targeted approach has ignored emerging contaminants.

In addition to the lack of a unified analytical method for measurement, and the interest in monitoring one material at the expense of others, there were challenges represented in:

  • 1- Other pollutants present in the environment may affect the sensitivity and selectivity of analytical tools, leading to challenges in distinguishing between PFAS and other substances.

  • 2- Some PFAS substances are found in very low concentrations in the environment, which hinders their detection by traditional methods.

  • 3- The wide variety of PFAS materials makes it difficult to obtain all reference standards relevant to analytical work.

  • 4- Current methods are difficult to implement, take a long time and are expensive.

The complex nature of PFAS and their widespread use has created challenges in their accurate detection and quantification (Shutterstock)

Based on these challenges, the research team from the British University of Birmingham, in cooperation with the German Federal Institute for Materials Research and Testing, realized their need for an innovative solution that is easy to implement, can detect substances even if they are in low concentrations, and be selective for those substances over other pollutants, and above all that is It cost little, which led them to the optical sensor.

Optical sensor.. How does it work?

The new device is an optical sensor that emits red light when exposed to ultraviolet rays, and changes in the fluorescence signal emitted by the metal in the sensor indicate the presence of PFAS substances.

According to the study, the mechanism of operation of this sensor can be simplified as follows:

  • Tiny light molecules:

    Imagine that we have small molecules that glow when light is shined on them. These molecules are made of a metal called iridium, and they have lipophilic chains (hydrocarbon chains of 6 and 12 carbon atoms, respectively) attached to them.

  • Special chains:

    These chains are like claws of molecules, meaning they help molecules form specific structures.

  • Detection of PFAS:

    When you put these molecules in water that contains PFAS, these materials will interfere with the molecules, changing the way they glow.

  • Long glowing light:

    What distinguishes these molecules is that they continue to glow for a long time, and we can measure the duration of their glow, and any changes in the glow tell us about the presence of PFAS substances.

  • Gold support:

    These particles bond to a surface made of gold, which helps it remain stable and not lose its glow.

The sensor is based on iridium metal inlaid with lipophilic chains and the two are mounted on a gold plate (Analytical Chemistry).

Detection up to 220 micrograms

“The sensor was able to detect 220 micrograms of PFAS per liter of water, which is suitable for industrial wastewater,” says Professor of Inorganic Chemistry and Photophysics, Professor Zoe Pickramino, in a press release issued by the University of Birmingham. “However, more work is needed.” Optimization to enhance sensitivity for detecting nanogram levels, especially in drinking water.”

Pickramino describes their invention as extremely important, adding, “PFAS are used in industrial environments because of their beneficial properties, for example in stain-resistant fabrics, but if they are not disposed of safely, these chemicals pose a real danger to life.” "This prototype is a big step forward in finding an effective, fast and accurate way to detect this contamination, helping to protect our natural world and potentially keep our drinking water clean."

Breakthrough awaits extended application challenge

For his part, Wael Abu Al-Majd, professor of chemical sciences at the Egyptian University of Germany, praised, in a telephone interview with Al-Jazeera Net, the results of the study that provided a solution to challenges that the research community has faced for years, but he stressed that this achievement must be placed in its normal size, which is that “it does not... "It is still in the laboratory framework, and has not been brought out for practical application on a large scale."

Abu Al-Majd adds that there are three questions that must be addressed in subsequent studies, so that this sensor can be adopted in the practical applied environment, and these questions are:

  • First:

      How stable is the luminous iridium metal over time, and how does the sensor’s performance hold up under different environmental conditions?

  • Second:

    Can the sensor provide reliable results consistently over long periods?

  • Third:

    How feasible is it to make the sensor portable for on-site measurements, especially in situations that require an immediate response?

Knut Rorack, head of the Department of Chemical and Optical Sensing at the German Federal Institute for Materials Research and Testing, and co-researcher of the study, promise to address these questions.

“Now that we have a prototype sensor chip, we intend to improve and integrate it to make it portable and more sensitive so that it can be used at the site of spills and determine the presence of these chemicals in drinking water,” Rorack says in the press release.

Source: Al Jazeera + websites