Microdialysis in Environmental Monitoring

Miró, Manuel; Frenzel, Wolfgang

doi:10.1002/9781118011294.ch17

Cited by 3 publications

(6 citation statements)

References 56 publications

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“…In addition to clinical applications, on-site environmental monitoring of lakes, streams and soil could be accomplished with these devices, provided the sensor is optimized for the particular analytes of interest [149]. Monitoring of nutrients and metabolic products in bioreactors is another potential application for the on-line analysis systems [45,46].…”

Section: Discussionmentioning

confidence: 99%

A review of microdialysis coupled to microchip electrophoresis for monitoring biological events

Saylor

Lunte

2015

Journal of Chromatography A

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Microdialysis is a powerful sampling technique that enables monitoring of dynamic processes in vitro and in vivo. The combination of microdialysis with chromatographic or electrophoretic methods yields along with selective detection methods yields a “separation-based sensor” capable of monitoring multiple analytes in near real time. Analysis of microdialysis samples requires techniques that are fast (<1 min), have low volume requirements (nL–pL), and, ideally, can be employed on-line. Microchip electrophoresis fulfills these requirements and also permits the possibility of integrating sample preparation and manipulation with detection strategies directly on-chip. Microdialysis coupled to microchip electrophoresis has been employed for monitoring biological events in vivo and in vitro. This review discusses technical considerations for coupling microdialysis sampling and microchip electrophoresis, including various interface designs, and current applications in the field.

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Section: Discussionmentioning

confidence: 99%

A review of microdialysis coupled to microchip electrophoresis for monitoring biological events

Saylor

Lunte

2015

Journal of Chromatography A

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“…The better reproducibility of the concentric microdialyzer is most likely a consequence of its sturdier configuration and easy to build probe design. 27 The concentric probe affording sampling under steady-state dialytic regime (RR close to 100%, slight variations from the nominal value are attributed to carryover effects) was therefore selected for the remainder of the studies. It should be noted that earlier researchers reported RR for lead in aqueous solutions of merely 40% using concentric probes furnished with 10-mm-long capillary membranes, 28,29 whereby frequent probe calibration was called for.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…The membrane separates the compounds according to their molecular dimension and only low molecular weight species can cross the permselective membrane. 22−25 The most salient attributes of the coupling of microdialysis sampling with the UBM test are as follows: 26,27 (I) the extraction medium is to be monitored without removal of gut fluids while maintaining the equilibria of the in vitro digestion because the small recipient volume for dialysates ensures minute uptake of species from the gastric and GI phases; (II) the possibility of straightforward automation of the sampling step itself; (III) the exclusion from the perfusate of proteins and humic acid and humin species from the soil matrix and metal chelates of large molecular weight; (IV) the monitoring of passive absorption as a function of time, giving rise to a more realistic insight into the temporal bioavailability of soil-borne metal species in the course of oral ingestion; and (V) as reported by van de Wiele et al, 13 dialysis-based separation methods are deemed most suitable to measure bioaccessible fractions of contaminants in the human gut and closely approach in vivo oral bioavailability.…”

Section: ■ Introductionmentioning

confidence: 99%

Automated Microdialysis-Based System for in Situ Microsampling and Investigation of Lead Bioavailability in Terrestrial Environments under Physiologically Based Extraction Conditions

Rosende

Magalhães

Segundo

et al. 2013

Environ. Sci. Technol.

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In situ automatic microdialysis sampling under batch-flow conditions is herein proposed for the first time for expedient assessment of the kinetics of lead bioaccessibility/bioavailability in contaminated and agricultural soils exploiting the harmonized physiologically based extraction test (UBM). Capitalized upon a concentric microdialysis probe immersed in synthetic gut fluids, the miniaturized flow system is harnessed for continuous monitoring of lead transfer across the permselective microdialysis membrane to mimic the diffusive transport of metal species through the epithelium of the stomach and of the small intestine. Besides, the addition of the UBM gastrointestinal fluid surrogates at a specified time frame is fully mechanized. Distinct microdialysis probe configurations and membranes types were investigated in detail to ensure passive sampling under steady-state dialytic conditions for lead. Using a 3-cm-long polysulfone membrane with averaged molecular weight cutoff of 30 kDa in a concentric probe and a perfusate flow rate of 2.0 μL min(-1), microdialysis relative recoveries in the gastric phase were close to 100%, thereby omitting the need for probe calibration. The automatic leaching method was validated in terms of bias in the analysis of four soils with different physicochemical properties and containing a wide range of lead content (16 ± 3 to 1216 ± 42 mg kg(-1)) using mass balance assessment as a quality control tool. No significant differences between the mass balance and the total lead concentration in the suite of analyzed soils were encountered (α = 0.05). Our finding that the extraction of soil-borne lead for merely one hour in the GI phase suffices for assessment of the bioavailable fraction as a result of the fast immobilization of lead species at near-neutral conditions would assist in providing risk assessment data from the UBM test on a short notice.

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“…Flow-through microdialysis, 14,15 which emerges from the neurobiological field, is a microsampling method recently introduced in the environmental analytical area. 16−20 A semipermeable hydrophilic hollow fiber is used as a molecular sieve to separate compounds on the basis of molecular weight with the concentration gradient as a driving force.…”

Section: ■ Introductionmentioning

confidence: 99%

“…13 The main drawbacks of this sampling technique involve the potential membrane clogging by the fine particles of soil, in which case the system might actually not be able of enduring flow backpressure, and the need of further leachate cleanup in troublesome environmental samples. Flow-through microdialysis, 14,15 which emerges from the neurobiological field, is a microsampling method recently introduced in the environmental analytical area. 16−20 A semipermeable hydrophilic hollow fiber is used as a molecular sieve to separate compounds on the basis of molecular weight with the concentration gradient as a driving force.…”

Section: ■ Introductionmentioning

confidence: 99%

Automatic Kinetic Bioaccessibility Assay of Lead in Soil Environments Using Flow-through Microdialysis as a Front End to Electrothermal Atomic Absorption Spectrometry

Cocovi-Solberg

Rosende

Miró

2014

Environ. Sci. Technol.

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In-line microdialysis is in this work hyphenated to electrothermal atomic absorption spectrometry via a dedicated flow-based interface for monitoring the batchwise leaching test endorsed by the Standards, Measurements and Testing Program (SM&T) of the European Commission. The bioaccessible pool of lead in soils is measured using 0.43 mol/L AcOH as extractant. The proposed method allows to gain knowledge of leaching kinetics at real-time, simplify the overall procedure by accurate detection of steady-state conditions and overcome sample filtration or centrifugation. Soil leachates were automatically sampled at specified timeframes (e.g, every 20 or 80 min), processed in an external container (where dilution can be applied at will) and further injected into the atomizer. The method was experimentally validated by comparison of in situ microdialysis sampling results with in-line microfiltration in two soils of varying physicochemical properties. A mathematical framework was used for discrimination of different metal fractions (that is, readily mobilizable against slowly mobilizable lead) and also for estimating the total extractable lead under actual steady-state conditions. We have demonstrated that bioaccessibility tests lasting 16 h as endorsed by SM&T might not suffice for ascertainment of maximum (steady-state) bioaccessibility of lead in terrestrial environments as demanded in risk assessment programs.

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Microdialysis in Environmental Monitoring

Cited by 3 publications

References 56 publications

A review of microdialysis coupled to microchip electrophoresis for monitoring biological events

A review of microdialysis coupled to microchip electrophoresis for monitoring biological events

Automated Microdialysis-Based System for in Situ Microsampling and Investigation of Lead Bioavailability in Terrestrial Environments under Physiologically Based Extraction Conditions

Automatic Kinetic Bioaccessibility Assay of Lead in Soil Environments Using Flow-through Microdialysis as a Front End to Electrothermal Atomic Absorption Spectrometry

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