'New way to make fragrances last longer'

Scientists have found a way to get fragrances to stick to the skin longer, instead of washing down the drain immediately after being applied.

From floral perfume to fruity body wash and shampoos, scents heavily influence consumer purchases.

However, for most, the smell does not last long after showering before it fades away.

"Companies incorporate a lot of fragrance oils in wash-off products, such as face washes and body scrubs, but the majority of these oils get washed away," said Martin S Vethamuthu from the University of Delaware in the US.

"My research team of solvers wants to help other companies amplify the efficacy, add to the allure and ensure the integrity of the retention of these fragrance notes in their products for skin and hair," said Vethamuthu.

His group adapted a device known as the twister bar headspace sorption extraction sensor, commonly used in the food industry to detect chemicals that could contribute to off-flavours or scents.

The sensor, presented at the National Meeting & Exposition of the American Chemical Society (ACS), absorbs trace amounts of volatile fragrances deposited on the skin after a shower.

Combined with gas chromatography-mass spectrometry, the team can gather a profile of the scents that remain on skin after rinsing off.

Then, fragrance evaluators are only brought in at the last step to validate and verify the results.

Vethamuthu also looked at ways to ensure the fragrances lasted longer by mixing them with various polymers, which help the scents remain on the skin.

"Polymers impact different fragrances in diverse ways," said Vethamuthu.

"By studying synthetic and naturally derived polymers, manufacturers can select the types of polymers they want to use that will correspond with the fragrance notes they want to prevail," he said.

Vethamuthu's group used the sensor to assess which fragrances still lingered on the skin several hours after the scents were applied.

However, there was a lot of trial and error to get to this point, since companies use many different combinations of scents, and the identities of those compounds are often kept secret.