Silver nanoparticles (AgNPs) based selective colorimetric sensor for the detection of D-arabinitol in a urine sample.

D-arabinitol is a sugar alcohol that is a typical metabolite of Candida species. The hydroxy group owned by D-arabinitol can function as a reducing agent that can reduce Ag⁺ to AgNPs. The resulting colloid is further stabilized by the addition of a capping agent. The capping agent used in this study was a combination of chitosan 1%(w/w) and PEG 6000 1% (w/w) (2:1) v/v. The formation of AgNPs causes an increase in the surface plasmon resonance spectra of the colloid solution at a wavelength of 430 nm with a slight blue shift. At the same time, the color of the solution changes from colorless to yellow colloid so that the absorbance can be observed using a spectrophotometer. The change in the absorbance value of the colloid produced is proportional to the concentration of D-arabinitol added, so that the amount of D-arabinitol in the sample can be quantified. Under optimum conditions, the resulting method shows good linearity with an R²-value of 0.9979 in the concentration range of D-arabinitol 100–2000 µM and Vxo value is 4.30%. The detection limit is 115.11 µM and the quantification limit is 383.70 µM. The repeatability (%RSD) is 0.78–1.94 and the % recovery in addition to urine samples is 93.27–103.70. This method is quite selective for other components present in urine. The analysis time is short, the number of samples required is only small, and does not require an organic solvent, so this method has the potential to be used in determining the levels of D-arabinitol in urine samples.