Sample Preconcentration Research Articles

Recent developments of capillary electrophoresis in seawater analysis

Recent applications of capillary electrophoresis (CE) to the determination of various seawater analytes are critically examined, with the aim to reveal method’s state-of-the-art and possible future research trends in the area. Given highly developed separation and detection methodology, emphasis is given to the most advantageous sample preconcentration strategies used to evolve the method’s practical utility, particularly to low-level analytes. Analytical performance of CE applied to seawater analysis is illustrated with a selection of real-world applications published from 2006, from which it appears that the primary developmental tendency is presently confined to a transit from inorganic to organic seawater analytes.

Determination of morpholinium ionic liquid cations in environmental water samples: development of solid-phase extraction method and ion chromatography.

An ion chromatography and solid-phase extraction method has been applied for the separation and detection of morpholinium cations in environmental water samples. The water samples were purified and enriched by a UF-SCX sulfonic acid extraction column and eluted with 0.5molL-1 phosphoric acid/sodium dihydrogen phosphate buffer solution/55% methanol. The target compounds were separated on a carboxylic acid cation exchange column with 5.0mmolL-1 methane sulfonic acid/2% acetonitrile as the mobile phase and direct conductivity detection. The method has been successfully applied to extract morpholinium cations from spiked water samples of Songhua River, Hulan River, East Lake, and Mopanshan Reservoir in China with the recoveries ranging from 75.0% to 98.3%. The relative standard deviations of intraday precision and interday precision are 2.1% and 5.9% or less, respectively. Using this method it is possible to preconcentrate water samples to 0.01-0.04mgL-1. The results show that the method is applicable to detection of morpholinium ionic liquid cations in environmental water samples and provides a new approach for monitoring ionic liquids in environmental water. Graphical abstract The analysis procedure of morpholinium ionic liquids in environmental water samples.

Determination of Acrylamide using Solid-phase Extraction and Gas Chromatography-Mass Spectrometry Selected Ion Monitoring in Roasted Cereal Foods

An analytical method has been developed for the determination of acrylamide in cereal-based foods. The method is based on extraction of acrylamide with water, cleaned up through a solid phase extraction (SPE) cartridge, followed by bromination of the acrylamide double bond. The reaction product (2,3-dibromopropionamide) is extracted with ethyl acetate and analyzed by gas chromatography coupled to mass spectrometry (GC/MS) in selected ion monitoring (SIM), employing acrylamide-2,3,3-d3 (AA-d3) as internal standard. The SPE process for sample preconcentration was performed on a commercially available SupelcleanTM Coconut Charcoal cartridge packed with active carbon. In this method, correlation coefficients (R2) of calibration curves appeared to be 0.9997 in the concentration range of 2.5~100 μg/kg. The method detection limit (MDL) and the limit of quantitation (LOQ) of acrylamide were 0.76 μg/kg and 2.32 μg/kg, respectively. The calibration curve showed good linearity above 0.9997 in the ranges of the 2.5~100 μg/kg. For validation purposes, recovery studies were carried out at one concentration levels (10 μg/kg, n=3). The intraday assay accuracy and precision were in the range 104% and 5.6%, respectively, and the interday assay accuracy and precision were in the range 95.8% and 5.3%, respectively. Key words: acrylamide, bromination, GC/MS, SPE, limit of quantitation (LOQ)

A new rapid procedure for simultaneous determination of glyphosate and AMPA in water at sub μg/L level

Glyphosate is the most used pesticide worldwide and its impact on the environment is becoming increasingly significant. Glyphosate and its main metabolite AMPA are frequently detected in streams and rivers. In this study, an analytical method is presented that combines Ultra-High Performance Liquid Chromatography with mass spectrometry (UHPLC–ESI-MS/MS) for glyphosate and AMPA analysis in environmental water samples. The method was developed starting from an application of Waters Corporation, and involves the use of an alternative derivatizing reagent, the commercially available AccQ·Tag™ Ultra Derivatization Kit (Waters Corporation, Milford, MA, USA). The kit contains the derivatizing reagent 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Derivatization takes place directly in the injection vial and no sample pre-concentration is needed. The derivatization is simple, quick and robust, which fits well within the needs of a routine method for the analysis of glyphosate and AMPA. Derivatized glyphosate and AMPA were recorded in positive ion mode. The method demonstrates a good linear relationship in the concentration range from 0.2 μg/L for glyphosate and 0.05 μg/L for AMPA to 100 μg/L and an accurate recovery. The method developed has been successfully applied to the determination of glyphosate and AMPA in 23 runoff water samples collected from a field in the Po Valley (North-East Italy), an agricultural area where glyphosate is widely used.

The application of the supported liquid membrane and molecularly imprinted polymers as solid acceptor phase for selective extraction of biochanin A from urine

An efficient sample clean-up and preconcentration procedure for phytoestrogens analysis in urine has been developed. It was based on a combination of solid phase extraction with hollow-fiber supported liquid membrane and molecularly imprinted beads (MIPs-HF-SLM-SPE). The molecularly imprinted polymers (MIPs) were synthesized by precipitation polymerization technique with biochanin A (BCA) as a template, giving narrowly dispersed microspheres with a regular shape. As the functional monomer, (dimethylamino)ethyl methacrylate (-DEM) turned out to be better than methacrylic acid (MAA) to get the best-imprinted effects. The MIPs used as sorbents in the MIPs-HF-SLM-SPE extraction process exhibited excellent binding selectivity for BCA, in comparison to non-imprinted polymers as well as its structural analogs (genistein and daidzein). Finally, the developed method was used to detect BCA in urine. Under optimal extraction conditions, the recovery of BCA in urine samples (using 4.5 mL sample spiked with 10 μg L−1) was over 41%, with a coefficient of variation (CV) < 6.6% (n = 5). The detection limit (LOD) and quantification limit (LOQ) for BCA analysis in urine were 0.41 and 1.36 μg L−1, respectively.

Deep eutectic solvent microextraction of lead(II), cobalt(II), nickel(II) and manganese(II) ions for the separation and preconcentration in some oil samples from Turkey prior to their microsampling flame atomic absorption spectrometric determination

A new liquid phase microextraction method based on deep eutectic solvent microextraction was developed for separation and preconcentration of lead, cobalt, nickel and manganese from edible oil samples like sunflower oil, baby oil, trout, waste frying oil and syrup-soaked pastry oil. A choline chloride deep eutectic solvent was used for microextraction. After extraction, analytical concentrations were determined by flame atomic absorption spectrometry. Effects of analytical parameters such as type and volume of deep eutectic solvent, sample volume, and temperature on extraction efficiency of lead, cobalt, nickel and manganese were optimized. The recoveries were generally >95%. The relative standard deviation (RSD, %, n = 7) of 50 μg/ L of analyte elements was in the range of 0.9–4.3%. Accuracy of presented microextraction method was checked by addition-recovery studies to oil samples. The presented deep eutectic solvent microextraction method was finally applied to edible oil samples and waste oils with different properties for the determination of analyte contents.

Reduction of Interferences Using Fe-Containing Metal-Organic Frameworks for Matrix Separation and Enhanced Photochemical Vapor Generation of Trace Bismuth.

Photochemical vapor generation (PVG) has emerged as a promising sample introduction method for atomic spectrometry in recent years. Despite its great success, a major impediment for the wide application of PVG is the interferences from the coexisting ions, especially transition-metal ions. In this work, iron and 1,3,5-benzenetricarboxylic (Fe-BTC), a Fe-containing metal-organic framework (MOF) material, was synthesized and first used as a platform integrating the sample matrix separation, preconcentration, and photocatalysis for the highly selective determination of elements by PVG. Bismuth was selected as a model analyte. Fe-BTC served not only as the photocatalyst for the PVG of Bi3+ but also as an efficient absorbent for the separation of analytes from the sample matrix. Compared with the previous PVG system, the performance of tolerating interferences toward coexisting ions of the proposed method has been greatly improved after using Fe-BTC-based matrix separation. Thus the excess of 10 mg L-1 of Co2+ and 100 mg L-1 of Cu2+, Ni2+, and Fe3+ caused no obvious interferences for 1 μg L-1 of Bi determination. Under the optimal conditions, the limit of detection (LOD, 3σ) of the developed method was 0.3 ng L-1 with the inductively coupled plasma-mass spectrometry (ICPMS) measurement, which could be lowered down to 0.04 ng L-1 after ten times of preconcentration with Fe-BTC prior to analysis. This method was successfully applied for the analysis of Bi in complicated sample matrices of soil (GBW07401), sediment (GBW07310), nickel-iron alloy (GBW01622), and nickel alloys (GBW01641) by the external calibration method.

Determination of Urinary Pterins by Capillary Electrophoresis Coupled with LED-Induced Fluorescence Detector.

Urinary pterins have been found as potential biomarkers in many pathophysiological conditions including inflammation, viral infections, and cancer. However, pterins determination in biological samples is difficult due to their degradation under exposure to air, light, and heat. Besides, they occur at shallow concentration levels, and thus, standard UV detectors cannot be used without additional sample preconcentration. On the other hand, ultra-sensitive laser-induced fluorescence (LIF) detection can be used since pterins exhibit native fluorescence. The main factor that limits an everyday use of LIF detectors is its high price. Here, an alternative detector, i.e., light-emitted diode induced fluorescence (LEDIF) detector, was evaluated for the determination of pterins in urine samples after capillary electrophoresis (CE) separation. An optimized method was validated in terms of linearity range, limit of detection (LOD), limit of quantification (LOQ), intra- and interday precision and accuracy, sample stability in the autosampler, and sample stability during the freezing/thawing cycle. The obtained LOD (0.1 µM) and LOQ (0.3 µM) values were three-order of magnitude lower compared to UV detector, and two orders of magnitude higher compared to previously reported house-built LIF detector. The applicability of the validated method was demonstrated in the analysis of urine samples from healthy individuals and cancer patients.

Near real-time enumeration of live and dead bacteria using a fibre-based spectroscopic device

A rapid, cost-effective and easy method that allows on-site determination of the concentration of live and dead bacterial cells using a fibre-based spectroscopic device (the optrode system) is proposed and demonstrated. Identification of live and dead bacteria was achieved by using the commercially available dyes SYTO 9 and propidium iodide, and fluorescence spectra were measured by the optrode. Three spectral processing methods were evaluated for their effectiveness in predicting the original bacterial concentration in the samples: principal components regression (PCR), partial least squares regression (PLSR) and support vector regression (SVR). Without any sample pre-concentration, PCR achieved the most reliable results. It was able to quantify live bacteria from 108 down to 106.2 bacteria/mL and showed the potential to detect as low as 105.7 bacteria/mL. Meanwhile, enumeration of dead bacteria using PCR was achieved between 108 and 107 bacteria/mL. The general procedures described in this article can be applied or modified for the enumeration of bacteria within populations stained with fluorescent dyes. The optrode is a promising device for the enumeration of live and dead bacterial populations particularly where rapid, on-site measurement and analysis is required.

Assessment of Tryptophan, Tryptophan Ethylester, and Melatonin Derivatives in Red Wine by SPE-HPLC-FL and SPE-HPLC-MS Methods.

Melatonin (MEL) is an indoleamine produced mainly by the pineal gland in vertebrates. It plays a significant role in the regulation of circadian rhythms, mitigation of sleeping disorders, and jet lag. This compound is synthetized from tryptophan (TRP) and it has been found in seeds, fruits, and fermented beverages, including wine. Wine is also a source of other tryptophan derivatives, the tryptophan ethylester (TEE) and MEL isomers (MISs), for which the biological properties need to be elucidated. An analytical method for the simultaneous quantification of TRP, TEE, and MEL was developed by a Solid Phase Extraction (SPE) of a preconcentration of wine followed by high performance liquid chromatography (HPLC) analysis either with fluorescence or mass spectrometer detectors. The analytical method showed a relative standard deviation (RSD) lower than 8%, except for TRP (RSD 10.5% in wine). The recovery was higher than 76%. The versatility of SPE preconcentrations allowed for the adequate preconcentration of wine sample as well as detection of low concentrations, an important aspect especially for MEL (detection limit 0.0023 µg/L). The proposed method proved to be suitable for assessing the investigated compounds in some red wine samples, where 74.4–256.2 µg/L and 0.038–0.063 µg/L of TEE and MEL were detected, respectively. Five MISs were also found in wine samples in concentrations up to 1.97 µg/L.

Micro-extraction by packed sorbent coupled on-line to a column-switching chromatography system – A case study on the determination of three beta-blockers in human urine

A new approach for the automation of Micro-Extraction by Packed Sorbent (MEPS) as a solid phase extraction technique coupled directly to a column-switching chromatography system was presented. A new on-line hyphenation of the modern micro-extraction procedure with liquid chromatography was developed and used for human urine sample clean-up and pre-concentration of three beta-blockers - metoprolol, labetalol and propranolol before separation and determination. A commercial MEPS C-18 cartridge was coupled using Teflon holders into an HPLC system through a high-pressure six-port switching valve. Chromatographic separation was performed on a Triart YMC C-18 (50 mm × 4.6 mm) analytical column with 5 μm multi-layered particles. The multi-layered particle column showed extremely low flow-resistance (<4.1 MPa) at a flow rate of 1.0 mL min−1, and thus direct connection with a MEPS cartridge was possible. A mixture of acetonitrile and an aqueous solution of 0.5% triethylamine with acetic acid, with pH adjusted to 4.5 in the linear gradient elution mode was used. This mobile phase eluted beta-blockers from the MEPS mini-column directly onto the analytical column where the separation was carried out. Metoprolol, labetalol and propranolol were detected by a fluorescence detector at the λex = 220 nm and λem = 315 nm wavelengths. The developed on-line MEPS-HPLC coupling showed satisfactory validation results with recovery ranging from 94.0 to 104.7% and precision in the range of 0.6–9.5% for all beta-blockers.

Development of a titanium dioxide-assisted preconcentration/on-site vapor-generation chip hyphenated with inductively coupled plasma-mass spectrometry for online determination of mercuric ions in urine samples

In this study, a novel automatic analytical methodology using a titanium dioxide (TiO2)-assisted preconcentration/on-site vapor-generation (VG) chip hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) for online determination of mercuric ions (Hg2+) was developed. Interestingly, the TiO2 nanoparticle (nano-TiO2) coating on the channel surface acted not only as a sorbent for preconcentration but also as a catalyst for photocatalyst-assisted VG. Under optimum operation conditions, the developed method was validated by analyzing the certified reference material (CRM) Seronorm™ Trace Elements Urine L-2 (freeze-dried human urine). Based on the obtained results, the dramatic reduction of “hands-on” manipulation and the elimination of hazardous materials (e.g., sodium borohydride (NaBH4) and stannous chloride (SnCl2)) from the process enabled a simple and ultraclean procedure with an extremely low detection limit of 0.75 ng L−1 for Hg2+ in urine samples. To the best of our knowledge, this is the first study to report the direct exploitation of a nano-TiO2-coated microfluidic device for online sample preconcentration and on-site VG prior to ICP-MS measurement.

Data trend shifts induced by method of concentration for trace metals in seawater: Automated online preconcentration vs. borohydride reductive coprecipitation of nearshore seawater samples for analysis of Ni, Cu, Zn, Cd, and Pb via ICP‐MS

AbstractThis research compares performance, reproducibility, and detection limits of ambient seawater analysis for trace metals using both borohydride reductive coprecipitation and an automated chelation column (seaFAST™ 2) preconcentration for matrix interferent elimination on total and dissolved grab samples in nearshore to marine waters, over a broad concentration range, prior to inductively coupled plasma mass spectrometry (ICP‐MS) injection. A move to an online preconcentration method both minimizes sample preparation, and eliminates correction errors when accounting for trace impurities in precipitated samples, induced via reagents. The reproducability of the online preconcentration method described, coupled with low blanks and method detection limits (MDLs), demonstrates the effectiveness of the automated procedure using ethylenediaminetriacetic and iminodiacetate acid chelation exchange resin and multianalyte determination by ICP‐MS for total and dissolved Ni, Cu, Zn, Cd, and Pb in marine water samples. Average CASS‐5 recoveries using the online preconcentration method (n = 9) were 109% ± 7%, 104% ± 5%, 103% ± 7%, 101% ± 3%, and 86% ± 8%, respectively. The MDLs obtained from the automated method for Ni, Cu, Zn, Cd, and Pb were 3.3, 1.8, 13.5, 4, and 10 times lower, respectively, than for the Borohydride method. There were statistically significant differences between the methods for CASS‐5 recoveries of Ni, Cu, Zn (p &lt; 0.0001), and Pb (p = 0.0024). Comparison of methods gave high concordance (rC ≥ 0.90) between methods for total and dissolved Ni, Cu, Zn, and Pb, and total Cd.

Development of a molecularly imprinted monolithic polymer disk for agitation-extraction of ecgonine methyl ester from environmental water

In this study, a new extraction approach based on rotating molecularly imprinted polymer (MIP) disks was developed. The preparation procedure of MIP-disk is simple. Firstly, in order to immobilize MIP onto the surface of polytetrafluoroethylene (PTFE) disk, previous modification and vinylization steps of this fluoropolymer were conducted. Then, MIP synthesis was done by in situ polymerization. The resulting MIP was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Afterwards, two ring magnets were placed in the sides of the MIP-disk to integrate the stirring and preconcentration of sample in just one step. To demonstrate the feasibility of this novel extraction system, the selective extraction of ecgonine methyl ester (EME) from water samples was performed. Extraction conditions were also evaluated and the extracts were analyzed by ion mobility spectrometry and by ultrahigh performance liquid chromatography-tandem mass spectrometry, allowing limits of detection of 13 and 75 ng L−1, respectively. Field surface water and wastewater were analyzed using the proposed methodology, being a good alternative for the fast and potentially portable methodology for in-field screening analysis.

Dispersive liquid–liquid microextraction based on green type solvents—"deep eutectic solvents"—for highly selective separation and efficient preconcentration of nickel in water samples

This study proposed a fast, feasible, and sensitive method for nickel preconcentration and separation in different actual samples through the use of deep eutectic solvent based dispersive liquid–liquid microextraction (DES-DLLME). This method involves dissolving a suitable extraction solvent in a dispersive solvent and its rapid syringing into water sample to obtain a turbid solution. Phase separation could be then carried out by centrifugation and the analyte can be determined. 2,2′-furildioxime was employed as the chelating agent through formation of a hydrophobic complex with nickel. To reach maximum recovery, some variables including type and volume of dispersive solvent, volume of extraction solvent, pH, 2,2′-furildioxime concentration, and salt concentration were optimized. Under optimal conditions, nickel calibration graph was linear in the range of 5.0–100 µg L−1. The detection limit and preconcentration factor were obtained as 1.7 µg L−1 and 40 µg L−1, respectively. Finally, this method was successfully applied for the extraction and determination of nickel in water samples with a relative recovery of 98.8–101.0%.

A new rapid protocol for 226Ra separation and preconcentration in natural water samples using molecular recognition technology for ICP-MS analysis

A new rapid protocol for 226Ra separation and preconcentration in natural water samples was developed before its determination by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). For this purpose, the commercially available Ra specific resin AnaLig® Ra-01 was used. This resin shows a high selectivity for radium in a large range of acid concentrations and no affinity or possible elution of 226Ra interfering elements. The distribution coefficients of Ra and other elements over a wide range of acid (HCl and HNO3) concentrations were obtained. Due to the high radium selectivity, the new developed protocol uses only 50 mg of dry resin and its performance was evaluated using 100 mL of three natural waters with different ionic strengths, spiked with a known quantity of 226Ra. Radium was successfully separated and preconcentrated yielding recoveries ranging between 72% and 86%. In parallel with the characterisation of the resin sorption properties, a detailed study of polyatomic interferences was performed on our ICP-MS allowing to identify the prominent elements favouring interferences at m/z = 226. Furthermore, a 226Ra sensitivity comparison between different ICP-MS instruments and configurations was done in order to determine high sensitivity conditions for radium analysis.

On-line sample preconcentration by polarity switching in floating electrode-integrated microchannel.

In this study, we found that the polarity switching was effective to enrich and separate fluorescent analytes which have weakly-dissociated groups in a floating platinum electrode (width, 50 µm; thickness, 2.5 µm)-integrated straight-channel in microchip electrophoresis (MCE). In the straight channel filled with an Alexa Flour 488 (AF488) solution, a sharp peak was observed after the polarity inversion with a 530-fold enhancement of the sensitivity relative to the conventional MCE analysis. By using a fluorescent pH indicator, we verified that a sharp high-pH zone was generated nearby the floating electrode and moved toward the anode with maintaining the high pH, which induced the sample enrichment like a dynamic pH junction mechanism. In the floating electrode-embedded channel, the mixture of AF488-labeled proteins was also well concentrated and separated within 100 s.

Critical evaluation of a seaFAST system for the analysis of trace metals in marine samples

A seawater preconcentration system (seaFAST) with offline sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS) detection was critically evaluated for ultra-low trace elemental analysis of Southern Ocean samples over a four-year period (2015–2018). The commercially available system employs two Nobias PA1 resin columns for buffer cleaning and sample preconcentration, allowing salt matrix removal with simultaneous extraction of a range of trace elements. With a primary focus on method simplicity and practicality, a range of experimental parameters relevant to oceanographic analysis were considered, including reduction of blank levels (over weeks and years), instrument conditioning, extraction efficiencies over different pH ranges (5.8–6.4), and preconcentration factors (~10–70 times). Conditions were optimised for the analysis of ten important trace elements (Cd, Co, Cu, Fe, Ga, Mn, Ni, Pb, Ti and Zn) in open ocean seawater samples, and included initial pre-cleaning and conditioning of the seaFAST unit for one week before each separate analytical sequence; a controlled narrow buffer pH of 6.20 ± 0.02 used for extraction; and a sample preconcentration factor of 10 for (relatively) concentrated rainwater or sea ice, 40 for typical seawater samples, and up to 67 times for seawater samples collected in the remote open ocean such as the Southern Ocean.Method accuracy (both short – days to weeks - and long term – months to years) were evaluated through extensive analysis of a range of oceanographic standard reference samples including SAFe D1 (n = 20), D2 (n = 3), S (n = 15), GEOTRACES GD (n = 6), GSC (n = 42) and GSP (n = 42), as well as NASS-6 (n = 6). Measured values for oceanographic samples were found to agree with consensus values to within ± 6% for Cd, Cu, Fe, Ni, Pb and Zn. Offsets were noted for Co (labile fraction only; no UV oxidation), Mn (difference also noted in other recent studies) and Ti (limited reference values). No consensus values currently exist for Ga. Iron and Mn in Southern Ocean samples were also independently verified via flow injection analysis methods (R2 = 0.95, n = 244 (Fe) and 0.92, n = 85 (Mn), paired t-test, p ≪0.05). Precisions over four years were evaluated through analysis of community seawater samples as well as a range of bulk in-house seawaters (3 sources, each n~100) and acid blanks (n = 250), and were typically found to be within 5–8%, depending on analyte and concentration.Values presented here represent one of the largest independent data sets for these reference samples, as well as the most documented comprehensive suite of GSP and GSC values currently available (consensus values have not yet been released). Samples covering a range of salinities (0–60) were investigated to demonstrate method versatility, with excellent recoveries noted using the seaFAST Nobias PA1 column (>98% for most elements, with 70–80% for Ga and Ti). By way of example, data is presented showing the application of the method to samples collected on the Kerguelen plateau in the Indian sector of the Southern Ocean (HEOBI voyage, January-February 2016) and in land-fast ice and brine collected near Davis station, Antarctica, in austral summer 2015 (with a salinity range from 0 to 73 g kg−1). Finally, a range of recommendations for successful implementation of a seaFAST system are provided, along with considerations for future investigation.

Continuous, quantifiable, and simple osmotic preconcentration and sensing within microfluidic devices

Insurmountable detection challenges will impede the development of many of the next-generation of lab-on-a-chip devices (e.g., point-of-care and real-time health monitors). Here we present the first membrane-based, microfluidic sample preconcentration method that is continuous, quantifiable, simple, and capable of working with any analyte. Forward osmosis rapidly concentrates analytes by removing water from a stream of sample fluid. 10-100X preconcentration is possible in mere minutes. This requires careful selection of the semi-permeable membrane and draw molecule; therefore, the osmosis performance of several classes of membranes and draw molecules were systematically optimized. Proof-of-concept preconcentration devices were characterized based on their concentration ability and fouling resistance. In-silico theoretical modeling predicts the experimental findings and provides an engineering toolkit for future designs. With this toolkit, inexpensive ready-for-manufacturing prototypes were also developed. These devices provide broad-spectrum detection improvements across many analytes and sensing modalities, enabling next-generation lab-on-a-chip devices.

Sample pre-concentration on a digital microfluidic platform for rapid AMR detection in urine.

There is a growing need for rapid diagnostic methods to support stewardship of antibiotics.