Detection of relative [Na+] and [K+] levels in sweat with optical measurements

Mahmoud Al-Omari, Kivanc Sel, Anja Mueller, Jeffery Edwards, Tolga Kaya

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


We describe the use of 2-hydroxy-1,4-naphthoquinone (HNQ, Lawsone) as a potential sweat electrolyte measurement marker. We use ultraviolet-visible absorbance measurements to determine the absorbance energy in a particular wavelength range (400 nm-500 nm). This novel approach allows us to eliminate the importance of the exact wavelength of the absorbance peak but find the integral of the range of interest. Although we numerically calculate the absorbance energy, it is imperative to use photodiodes to measure the intensity of the transmitted light that is fabricated particularly for the range of interest for future device implementations. We explored various mixing ratios of water and acetone to find the optimum solvent that would give the most sensitive and accurate relative electrolyte sensing. The pH value was also modified to see the effect on the absorbance energy and intensity. A representative group of subjects were used to collect sweat from the dehydration and hyperhydration cases. The results are convincing that HNQ solutions can be used as a wearable, continuous sweat sensor.

Original languageEnglish
Article number203107
JournalJournal of Applied Physics
Issue number20
StatePublished - May 28 2014


Dive into the research topics of 'Detection of relative [Na+] and [K+] levels in sweat with optical measurements'. Together they form a unique fingerprint.

Cite this