Recent developments in automatic solid-phase extraction with renewable surfaces exploiting flow-based approaches

Abstract

. (2008). Recent developments in automatic solid-phase extraction with renewable surfaces exploiting flow-based approaches. TRAC -Trends in Analytical Chemistry, 27(9), 749-761. DOI: 10.1016749-761. DOI: 10. /j.trac.2008 TrAC MS:08-00052-REVISED Abstract: Solid-phase extraction (SPE) has been consolidated as the most versatile sample processing method for removal of interfering species and/or analyte enrichment. Although significant advances have been conducted over the past two decades for automation of the entire analytical protocol involving SPE via flow injection approaches, on-line SPE assays performed in a permanent mode lack sufficient reliability as a consequence of the progressive tighter packing of the bead reactor, contamination of the solid surfaces and potential leakage of functional moieties. This article overviews the current state-of-the-art of an appealing tool for overcoming the above shortcomings, the so-called bead injection (BI) analysis, based on automated renewal of the sorbent material per assay exploiting the various generations of flow injection analysis. It addresses novel instrumental developments for implementation of BI and a number of alternatives for on-line chemical derivatization reactions and pinpoints the most common instrumental detection techniques utilised. Relevant environmental and bioanalytical applications reported within the past few years are presented and discussed in detail.

Sequential injection‐bead injection‐lab‐on‐valve coupled to high‐performance liquid chromatography for online renewable micro‐solid‐phase extraction of carbamate residues in food and environmental samples

“…The third generation of flow injection (FI), sequential injection-lab-onvalve (SI-LOV) in combination with bead injection (BI) [23][24][25], has played an important role for sample pretreatment prior to atomic spectrometric measurement via online manipulation [26][27][28][29]. The concept of the use of a renewable surface BI scheme allows the packing material to be renewed after every analytical run in order to avoid carryover effects.…”

Solid-phase extractions in flow analysis

“…Poly(styrene-divinylbenzene), agarose or poly(vinylpirrolidone) are commonly used as beads, and uniform spherical shape and size is preferred (Miró et al 2008). Otherwise, a re-suspension stage is required to promote fluidization, which significantly improves precision in comparison to direct aspiration of suspensions of non-uniform beads, 1.6 < r.s.d.…”

Determination of As, Cd, Cu, Hg and Pb in biological samples by modern electrothermal atomic absorption spectrometry

“…However, on line LSE performed with permanent packed-columns may suffer from sufficient reliability as a consequence of the progressive contamination of the solid surfaces of the beads and the potential stripping of surface functional moieties. Recently, so-called bead-injection (BI) analysis has overcome such shortcomings as renewal of the sorbent material occurs in each analytical cycle by flow programming [130,131]. Lab-on-valve (LOV) is a novel and powerful method in flow analysis which has introduced new advances as all operations can be achieved in a miniaturized, automated fashion under strictly controlled conditions [132].…”