Simplified, Cost Effective, and Accurate Calculation of Critical Wavelength via the MATLAB Software


  • Camille Keisha Mahendra
  • Cayvern Kishen Mahendra
  • Priyia Pusparajah
  • Thet-Thet Htar
  • Lay-Hong Chuah
  • Acharaporn Duangjai
  • Tahir Mehmood Khan
  • Yoon Yen Yow
  • Yatinesh Kumari
  • Bey Hing Goh



The use of sunscreens in our daily lives to reduce UV exposure on our skin is a good measure against photoaging. However, the current active ingredients in the market are not able to cover the entire spectrum range of UVA and UVB. Therefore, broader spectrum compounds are constantly being searched by cosmetic companies to replace the commercially available UV filters. In this study, an experimental model utilizing the MATLAB software was developed to measure a compound’s critical wavelength (λc). The purpose of this research was to ease the cost and speed up the screening of bioactive compounds for photoprotective properties while maintaining accuracy in the process. In this paper, the measurement of caffeic acid, gallic acid, and pinocembrin’s critical wavelength in the MATLAB software was explained in a step-by-step guide. This was done to create an understandable and executable procedure for future researchers to utilize. Subsequently, from the results, the critical wavelength of caffeic acid, gallic acid, and pinocembrin was 378.2nm, 324.6nm, and 364.8nm, respectively. This shows that caffeic acid has the broadest absorbance spectrum, followed by pinocembrin, and finally gallic acid. Thus, it may be possible that caffeic acid might have stronger photoprotective abilities as compared to pinocembrin and gallic acid, based on its critical wavelength.