Automated analytical procedure using multicommuted flow analysis and organic solvent extraction controlled by an Arduino Due board for photometric determination of zinc in water

Determination of zinc complexation with an immobilized reagent for the analysis of environmental objects

Although significant progress has been made in the effective measurement of Zn(II), Аlizarin red S (ARS) was immobilized on polyethylene polyamine-modified polyacrylonitrile (PPF-1) via a new matrix. This approach allows the detection of low levels of Zn(II) ions in various water samples via preconcentrated atomic absorption spectrometry. The use of PPF-1 in a polymer matrix for zinc preconcentration presents several advantages over traditional sorbtion-spectroscopic methods, including reduced cost, high zinc recovery, increased sensitivity, and selectivity. The maximum sensitivity of Zn(II) determination using selectively immobilized ARS was 522 nm. The optimal pH for Zn(II) detection at ambient temperature was found to be 5.0. The adsorption rate was approximately, with a linear detection range of 6.5-40 mg × L-1 and a detection limit of 0.6 mg × L-1 The immobilized ARS polymer matrix demonstrated selective Zn(II) determination even in the presence of solutions of Na+, K+, Ca2+, Mg2+, Ba2+, SO42-, CO32-, HCO3- and Cl-. The Zn(II) concentrations in various water samples were measured with high precision, revealing an adsorption efficiency of 98-99 % when the ARS/PPF-1 matrix was used. This method was developed for the determination of Zn(II) ions in technogenic, waste, and industrial fluids via sorption spectroscopy.

Automated H2O2 monitoring during photo-Fenton processes using an Arduino self-assembled automatic system

A cheap and easy to use Arduino self-assembled automatic system was employed to continuously monitor the hydrogen peroxide consumption during the photo-Fenton degradation of caffeine, selected as model target compound. The automatic system made it possible to measure the H2O2 concentration in the reaction cell via a colorimetric reaction and to take samples for HPLC analysis minimising the operator manual intervention and exposure to UV radiation. The obtained results were compared in terms of LOD and LOQ with H2O2 measurements manually performed using UV-Vis spectrophotometry, evidencing better analytical performance when using the automatic system; LOD and LOQ were respectively 0.032 mM and 0.106 mM for the automatic system against 0.064 mM and 0.213 mM for UV-Vis spectrophotometry. Furthermore, the photo-Fenton treatment was optimised by means of a Design of Experiments (DoE) investigating the effect of added H2O2 concentration, iron concentration and caffeine initial concentration on system performances. The use of the automatic device for such monitoring provided several advantages: automation (with consequent reduction of the workload), measurement increased precision, reduced reagents consumption and waste production in agreement with the principles of Green Analytical Chemistry.

Portable stirring device for the on-site extraction of environmental waters using magnetic hydrophilic-lipophilic balance tape

The spatial heterogeneity of environmental systems makes sampling at multiple locations crucial to provide complete and representative information. The on-site application of an extraction technique simplifies the sampling logistics, increasing sample integrity during transportation and storage. This article presents a portable, simple, and low-cost device capable of performing the simultaneous on-site extraction of several environmental water samples. The device consists of a small electric motor integrated into the plastic cap of a conventional glass bottle and operated with a portable battery. The electric motor provides stirring to a novel magnetic sorptive phase based on the deposition of hydrophilic-lipophilic balance (HLB) particles over a magnetic tape. The use of open technology makes the device globally affordable. In this first approach, the isolation and preconcentration of atrazine and simazine have been selected as proof of concept. Using an internal standard made unnecessary the adjustment of the ionic strength before the extraction, thus simplifying the analytical procedure. Under the optimum conditions and using direct infusion mass spectrometry as the instrumental technique, detection limits as low as 15 ng/L were obtained. The precision calculated at three different levels was better than 8.3%. The accuracy, calculated with spiked samples, indicates the applicability of the approach for environmental water analysis.