title: Ultrasensitive and Rapid Determination of Folic Acid Using Ag Nanoparticles Enhanced 1, 10-Phenantroline-Terbium (III) Sensitized Fluorescence.
abstract: A novel spectrofluorimetric probe based on Ag nanoparticle (AgNPs)-enhanced terbium (III) (Tb) fluorescence was introduced for the sensitive determination of folic acid (FA). The effect of gold and silver nanoparticles in different size was investigated on the well-known Tb sensitized fluorescence emission of 1, 10-phenantroline (Phen). The greatest fluorescence intensity was observed in the presence of AgNPs with a diameter of ~6 nm maybe due to their highest surface area. Furthermore, it's discovered that FA can form Tb-Phen -FA ternary complexes and cause a notable diminution in this enhanced fluorescence system. Based on this finding, a high sensitive and selective method was developed for the determination of FA. Effects of various parameters like Ag NPs, Phen and Tb(3+) concentration and pH of media were investigated. In the optimum circumstances, the fluorescence emission of AgNPs-Phen-Tb collection was declined linearly by increasing the concentration of FA in the range of 0.5 to 110 nmol L(-1). Limits of detection and quantification were achieved to be 0.21 and 0.62 nmol  L(-1), respectively. The method has good linearity, recovery, reproducibility and sensitivity, and was adequately exploited to follow FA content in pharmaceutical, fortified flour and human urine samples.
authors.affiliation: Department of Midwifery, Bonab Branch, Islamic Azad University, Bonab, Iran.
authors.forename: Robab
authors.initials: R
authors.lastname: Hassanzadeh
authors.affiliation: Tabriz Branch, Islamic Azad University, Tabriz, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Lotfi
authors.affiliation: Department of Chemistry, Faculty of Science, Azarbaijan Shahid Madani University, Tabriz, East Azarbaijan, Iran.
authors.forename: Nafiseh
authors.initials: N
authors.lastname: Bagheri
authors.affiliation: Tabriz Branch, Islamic Azad University, Tabriz, Iran. Javadhassanzadeh63@gmail.com.
authors.forename: Javad
authors.initials: J
authors.lastname: Hassanzadeh
keywords: Folic acid; Fortified flour; Nanoparticles; Sensitized fluorescence; Terbium