Determination of Iron in Environmental Water Samples by FIA-TLS

Abstract

The determination of low concentration of iron in natural waters can be difficult due to the complexity of natural water, but primarily because it requires preconcentration of the sample with solvent extraction. In this work we report on results of thermal lens spectrometry (TLS) coupled to flow injection analysis (FIA) as a highly sensitive FIA-TLS method of iron detection. The concentration of iron redox species was determined using 1,10-phenanthroline (PHN), that forms stable complexes with Fe(II) ions which are characterized by an absorption maximum at 508 nm. The TLS system using a 633 nm probe laser and 530 nm pump laser beam was exploited for on-line detection in flow injection analysis, where a PHN solution was used as the carrier solution for FIA. The concentration of the complexing agent affects the quality of the TLS signal, and the optimal concentration was found at 1 mM PHN. The achieved limits of detection (LODs) for Fe(II) and total iron were 33 nM for Fe(II) and 21 nM for total iron concentration. The method was further validated by determining the linear concentration range, specificity in terms of analytical yield and by determining concentration of iron in a water sample from a local water stream.

Understanding the Role of Complexation of Fluoroquinolone and β-Lactam Antibiotics with Iron (III) on the Photodegradation under Solar Light and UVC Light

“…The environmental concentration of the ferric ions varies depending on the nature of the water [10,11]. Then, the role of the iron concentration on the degradation should be evaluated.…”

“…In environmental water, drinking water, or even in wastewater, the presence of metallic cations, such as iron, is common (III) [10,11]. Because of the presence of multiple functional groups containing alone pairs (e.g., carboxylic acid, amide, amine, ketone, reduced forms of sulfur) on the β-lactams and fluoroquinolones, these antibiotics can form complexes with cations of metals, such as ferric ions.…”

Implementation of high performance liquid chromatography coupled to thermal lens spectrometry (HPLC-TLS) for quantification of pyranoanthocyanins during fermentation of Pinot Noir grapes

“…Since then TLS technique found applications in analytical chemistry, physical chemistry, physics, biochemistry, etc. [31,[33][34][35][36][37][38][39][40][41][42][43][44][45][46]. It provides high sensitivity for detection of non-fluorescent analytes and enables analysis of small volume (sub μL) samples as well as on-line detection in liquid chromatography and flow injection analysis.…”