Abstract We report a simple nanospray sheath‐flow interface for capillary electrophoresis. This relies on electrokinetic flow to drive both the separation and electrospray; no mechanical pump is used sheath flow. system was interfaced with an LCQ mass spectrometer. The best results were observed 2‐µm diameter emitter tip 1‐mm spacing between tip. Under these conditions, detection limits (3 σ ) of 100 amol obtained insulin receptor fragment 1142‐1153. efficiency exceeded 200,000 plates this...

Label-free, chemical specific detection in flow is important for high throughput characterization of analytes applications such as injection analysis, electrophoresis, and chromatography. We have developed a surface-enhanced Raman scattering (SERS) detector capable ultrasensitive optical on the millisecond time scale. The device employs hydrodynamic focusing to improve SERS channel where sheath confines analyte molecules eluted from fused silica capillary over planar SERS-active substrate....

Fluorescence tends to produce the lowest detection limits for most forms of capillary electrophoresis. Two issues have discouraged its use in isoelectric focusing. The first issue is fluorescent labeling proteins. Most reagents react with lysine residues and convert cationic residue a neutral or anionic product. At best, these perturb point protein. worse, they each protein into hundreds different products that confound analysis. second large background signal generated by impurities within...

On line SERS detection of nanomolar concentrations rhodamine structural isomers separated by capillary zone electrophoresis is reported.

Characterization of both the acidic and basic regions imaged capillary isoelectric focusing (icIEF) profile an IgG1 antibody was achieved through preparative immobilized pH gradient (IPG-IEF) fractionation. Recent attempts at using this method to fractionate charge variants monoclonal antibodies (mAbs) have shown promising results, but identification chemical modifications in limited species. We optimized achieve enrichment each variant across icIEF mAb. The fractionation followed by...

The dynamic range of capillary electrophoresis analysis is ultimately limited by molecular shot noise at low concentrations and concentration-induced band broadening high concentrations. We report a system that approaches these fundamental limits. A laser-induced fluorescence detector reported employs cascade four fiber-optic beam splitters connected in series to generate primary signal attenuated signals, each monitored single-photon counting avalanche photodiode. Appropriate scaling the...

CIEF and CZE are coupled with LIF detection to create an ultrasensitive 2-D separation method for proteins. In this method, two capillaries joined through a buffer-filled interface. Separate power supplies control the potential at injection end of first capillary interface; detector is held ground potential. Proteins labeled fluorogenic reagent Chromeo P503, which preserves isoelectric point protein. The proteins were mixed ampholytes injected into first-dimension capillary. A focusing step...

Reversed phase liquid chromatography with mass spectrometry (RPLC-MS) peptide mapping is routinely used for interrogating molecular and structural attributes such as amino acid composition, sequence variants, post-translational modifications (PTMs) in antibody-derived therapeutics. RPLC has some limitations that often impact the analysis of certain peptides including large hydrophobic peptides, hydrophilic di-/tripeptides glycopeptides. Capillary zone electrophoresis (CZE-MS) great potential...

We present a design for sheath-flow cuvette that uses relatively inexpensive quartz cuvette. The has high optical quality square flow chamber is fused to tubes at each end. PEEK/TEFZEL fittings hold and seal the without putting strain on performance of evaluated as laser-induced fluorescence detector capillary electrophoresis. produces mass detection limits 50 yoctomoles (30 copies) 5-carboxyl tetramethylrhodamine (5 TAMRA SE) with separation efficiency 400 000 theoretical plates.

A coaxial thermal lens microscope was used to generate images based on both the absorbance and diffusivity of histological samples. pump beam modulated at frequencies ranging from 50 kHz 5 MHz using an acousto-optic modulator. The a CW probe were combined with dichroic mirror, directed into inverted microscope, focused onto specimen. change in transmitted beam's center intensity detected photodiode. photodiode's signal reference modulator sent high-speed lock-in amplifier. in-phase...

Peptide mapping with mass spectrometry (MS) detection is a powerful technique routinely used for interrogating physicochemical properties of proteins. benefits from an efficient front-end separation to increase selectivity and reduce complexity prior MS detection. The most commonly method peptide based on reverse phase liquid chromatography spectrometry. Capillary zone electrophoresis (CZE-MS) orthogonal growing attention biotherapeutic proteins due its high efficiency sensitivity. However,...

We report an improved interface for two-dimensional capillary electrophoresis. This is based on tubing and a Plexiglas chip, both of which were milled using micro-dicing saw. The was evaluated compared to traditional design pseudo one-dimensional observe less than 70% transfer efficiency the greater 90% with this new interface.

A finite element analysis method for numerical modeling of the photothermal deflection spectroscopy aerosols is presented. The models simulate pulse-laser excited from collected on a plane surface substrate in air medium. influence aerosol and properties transient signal examined. We have previously obtained experimental results spectrometry deposited onto plate an impactor system (O. O. Dada S. E. Bialkowski, Appl. Spectrosc. 62, 1336 (2008)). This paper supports validity presented that...

Photothermal lens measurements and finite element modeling are used to examine the physical changes taking place in optical filter glasses. Colored glass neutral density filters found have a strong positive temperature-dependent refractive index change. The overall change is thought be consequence of complex counteracting factors: stress-induced birefringence, polarizability, structural network, carrier CdSxSe1-x microcrystals that produce properties these Finite analysis (FEA) temperature...

A prototype small photothermal deflection apparatus was constructed on a laboratory bench. Not including excitation laser, data collection computer, and gas pumps, the fits bench space with footprint of about 10 cm × cm. The lends itself to miniaturization in future assemblies. tested relative conventional laboratory-scale apparatus. Digital filtering procedures developed this were used collect analyze data. Numerical simulation signal is performed accurately predict heat flow process as...

Experimental results for photothermal lens measurements are compared to finite elemental analysis models commercial colored glass filters. Finite software is used model the effect by simulating coupling of heat both within sample and out surroundings. Modeling shows that transfer between surface air fluid has a significant on predicted time-dependent signals. For comparison with experimental signals, simple equation based element result proposed accounting variance data where this type...

The potential of mid-infrared photothermal deflection spectrometry for aerosol analysis is demonstrated. Ammonium nitrate aerosols are deposited on a flat substrate using micro-orifice uniform deposit impactor (MOUDI). Photothermal spectroscopy with optical beam (mirage effect) used to detect aerosols. from measured by pulsed infrared laser light heat up collected the substrate. signal obtained measuring position spot as it passes near heated surface. results indicate non-rotating impaction...

Capillary electrophoresis coupled with sheath-flow laser-induced fluorescence (LIF) detection has been shown to offer outstanding sensitivity for chemical and biochemical analysis. However, a major drawback remains the complexity of optical configuration traditionally employed. Here we present simplified confocal optics based on fiber micro gradient-index (GRIN) lenses modular design in capillary fluorescence. We demonstrate use system cuvette as detector electrophoresis. The system's...

Experimental results for photothermal lens measurements are compared to finite elemental analysis models commercial colored glass filters. Finite software is used model the effect by simulating coupling of heat both within sample and out surroundings. Modeling shows that transfer between surface air fluid has a significant on predicted time dependent signals. For comparison with experimental signals, simple equation based element result proposed accounting variance data where this type...

Oil and gas industrial wastewater pose significant threats to aquatic organisms when discharged into the environment without proper treatment. This study aimed assess acute toxicity genotoxic responses in African mud catfish, Clarias gariepinus, exposed biocides aqueous ammonia, aligning with objectives of UN Decade Restoration Sustainable Development Goals (SDGs). The commenced a 96-hour assay determine 96 h LC50 values. Subsequently, chronic evaluation was conducted over 28 days using...

The UN Decade for Safe Water underscores the importance of evaluating toxicities industrial wastewater discharges to protect aquatic ecosystems. This study assessed influent and effluent from a textile establishment in Lagos State, Nigeria, using 96-hour acute non-renewal bioassay system with juvenile Oreochromis niloticus. Various parameters, including pH, conductivity, color, total suspended solids (TSS), dissolved (TDS), alkalinity, acidity, biological oxygen demand (BOD), chemical (COD),...