Water is a fundamental resource, yet various contaminants increasingly threaten its quality, necessitating effective remediation strategies.

A novel, simple, sensitive and precise spectrofluorimetric method is developed for measuring the activity of the α-amylase enzyme in human saliva. The remarkable quenching of the luminescence intensity at 634 nm of nano CdS doped in a sol–gel matrix by various concentrations of maltose (produced from the reaction of the enzyme with the starch substrate) was successfully used as an optical sensor for the assessment of α-amylase activity. The calibration plot was achieved over the concentration range 4.8 × 10⁻¹⁰ to 1.2 × 10⁻⁵ mol L⁻¹ maltose with a correlation coefficient of 0.999 and a detection limit of 5.7 × 10⁻¹¹ mol L⁻¹. The method was used satisfactorily for assessment of the α-amylase activity in a number of human saliva samples collected from various healthy volunteers.

The absorption efficiency of any drug in blood is of prime importance. Compounds having the general formula: , where (M = Cu(II) or Fe(III), n = 2 or 1 , FO = folate anion, x = 2 or 3 with respect), were prepared, and their absorption efficiency in rodent′s blood was determined. The obtained compounds were characterized by elemental analysis, infrared as well as thermogravimetric analysis and polarization of light. The results suggest that the two folate complexes were formed in 1 : 2 molar ratio (metal : folic acid) which acted as a bidentate ligand through both carboxylic groups. Polarization of light proved that the folate complexes have symmetric geometry. Biological application proved that Cu(II) and Fe(III) complexes were absorbed more efficiently in rodent blood than folic acid itself.