Determination of amino acids in gym supplements using digital images and paper platform coupled to diffuse reflectance spectroscopy and USB device.

New and reliable methodologies are described for the determination of amino acids in gym supplements, offering rapid and clean analysis, with low generation of waste. The proposed methods are based on the reaction between ninhydrin and amino acids in acetate buffer medium (pH 4.75).

Application of Multi-energy Calibration for Determination of Chromium and Nickel in Nickeliferous Ores by Laser-induced Breakdown Spectroscopy.

A multi-energy calibration method was applied for the determination of chromium and nickel in nickeliferous ores by laser-induced breakdown spectroscopy. For the optimization of the laser-induced breakdown spectroscopy parameters, such as laser fluence and delay time, an experimental study was conducted. The best results in terms of trueness were observed using a laser fluence and a delay time of 2500 J/cm and 1.

A fast method for the determination of lead in honey samples using stabilizer-free silver nanoparticles.

A sensitive, rapid and robust method based on the use of stabilizer-free silver nanoparticles was developed for lead detection in honey. Silver nanoparticles were synthesized without the presence of any stabilizers using silver nitrate and sodium borohydride as precursors where the latter was applied as reducing agent. The optimization of the experimental variables (AgNO and NaBH) for the formation of the nanoparticles was carried out using varying volumes of these solutions.

A simple and rapid screening method for sulfonamides in honey using a flow injection system coupled to a liquid waveguide capillary cell.

A rapid and simple screening method was developed for the determination of sulfonamides in honey samples by flow injection analysis (FIA) coupled to a liquid waveguide capillary cell. The proposed method is based on the reaction between sulfonamides and p-dimethylaminocinnamaldehyde (p-DAC) in the presence of sodium dodecylsulate (SDS) in dilute acid medium (hydrochloric acid), with the reaction product being measured spectrophotometrically at λ(max) = 565 nm. Experimental design methodology was used to optimize the analytical conditions.