Determination of trace zinc in seawater by coupling solid phase extraction and fluorescence detection in the Lab-On-Valve format

Abstract

By virtue of their compactness, long-term stability, minimal reagent consumption and robustness, miniaturized sequential injection instruments are well suited for automation of assays onboard research ships. However, in order to reach the sensitivity and limit of detection required for open-ocean determinations of trace elements, it is necessary to preconcentrate the analyte prior its derivatization and subsequent detection by fluorescence. In this work, a novel method for the determination of dissolved zinc (Zn) at subnanomolar levels in seawater is described. The proposed method combines, for

From continuous flow analysis to programmable Flow Injection techniques. A history and tutorial of emerging methodologies

“…Yet another interesting feature of this instrument is that it allows coupling of two steps of an analytical protocol; separation of the target analyte from the matrix and its subsequent detection and quantification. Combination of sorbent extraction with fluorescence detection, applied for assay of traces of zinc in sea water is the first application of this approach [6].…”

Developing Autonomous Observing Systems for Micronutrient Trace Metals

“…Micro-Sequential Injection analyzers are another class of automated, miniaturized wet chemical analyzers with potential for in situ deployment (Figure 4). Presently best suited to laboratory and shipboard determinations (Oliveira et al, 2015;Grand et al, 2016), these compact instruments share many of the features that have made FIA systems popular for shipboard metal micronutrient determinations. Indeed, Micro-Sequential Injection analyzers are made using commercially available components, are easily customizable, fully automated, and can operate absorbance, fluorescence, and chemiluminescence determinations coupled with analyte preconcentration to reach detection limits in the sub-nanomolar range.…”

“…However, unlike FIA systems, they are characterized with low reagent consumption (100s of microliters per sample), are less prone to drift, and do not require much maintenance, which make micro-Sequential Injection analyzers better suited to long-term unattended operation relative to their FIA counterparts. At present, the application of micro-Sequential Injection to micronutrient metal determinations at open ocean levels is limited to the shipboard analysis of total dissolved Zn and Fe, with reported detection limits of 50 pM for Zn (Grand et al, 2016) and 1 nM for Fe (II) (Oliveira et al, 2015). Micro-Sequential Injection is thus a proven analytical technology for sub-nanomolar metal micronutrient detection, but unlike Labon-Chip platforms, micro-Sequential analyzers have not yet been engineered for in situ deployment.…”

Separation/preconcentration of Cr(VI) with modified single-drop microextraction device and determination by GFAAS

“…Further improvement of these systems was based on the miniaturization of the flow manifolds. The result was a micro sequential injection analysis Lab-On-Valve (μSI-LOV), which alleviated the majority of the drawbacks of FIA methods 25 and it had a small size with a mini spectrometer, which was developed for a field operated chromium speciation method. 26 Nowadays the current trend is the simplification and miniaturization of sample preparation techniques.…”