Green synthesis of carbon quantum dots from teak leaves biomass for in situ precipitation and regenerative-removal of methylene blue-dye.

The objective of this study was to completely eliminate environmentally harmful cationic organic dye from aqueous solutions using the one-step ultrasonication method, renowned for its energy efficiency, user-friendliness, and minimal requirement for chemical resources, making it particularly suitable for large-scale applications. To achieve effective environmental remediation, we employed carbon dots derived from teak leaf biomass (TBCDs) layered with graphene oxide. We conducted a thorough characterization of the TBCDs using UV-vis spectroscopy (with absorption peaks at λmax = 208 and 276 nm), FTIR spectroscopy (confirming the presence of various functional groups including -OH, -CH, C = O, COO-, C-O-C, and = C-H), Raman spectroscopy (with bands at 1369 cm-1 (D-Band) and 1550 cm-1 (G-Band), and an intensity ratio (ID/IG) = 0.88, indicating structural defects correlated with the sp3 hybridization sites on the TBCDs), XRD analysis (indicating an amorphous nature of particles), HRTEM imaging (showing homogeneous dispersal of TBCDs with typical sizes ranging from 2 to 10 nm), FESEM analysis (showing a flat surface and minuscule particles), and Zeta potential analysis (revealing a surface charge peak at -51.0 mV). Our adsorption experiments yielded significant results, with a substantial 50.1 % removal rate and an impressive adsorption capacity of 735.2 mg g-1. Theoretical adsorption parameters were rigorously analyzed to understand the adsorption behavior, surface interactions, and mechanisms. Among these models, the Langmuir isotherm in conjunction with pseudo-second-order kinetics provided an exceptional fit (with R2 values closer to 1) for our system. The Gibbs free energy (ΔG) was found to be negative at all temperatures, indicating the spontaneity of the reaction. Regarding mechanism, electrostatic attraction ((+ve) MB dye + (- ve) TBCDs), π-π stacking adsorption facilitated by the graphitic structure, formation of multiple hydrogen bonds due to polar functional groups, and a pore-filling mechanism wherein the cationic MB dye fills the pores of TBCDs with graphene oxide layers, forming an adduct were identified. Furthermore, we demonstrated the regenerative capacity of our system by effectively extracting and recovering the MB dye (with a regeneration rate of 77.1%), utilizing ethyl alcohol as the solvent. These findings not only provide valuable insights into the adsorption capabilities of TBCDs but also highlight the potential of our approach in the recovery of expensive cationic organic dye compounds from polluted environments.

Copper oxide nanoparticles fabricated by green chemistry using Tribulus terrestris seed natural extract-photocatalyst and green electrodes for energy storage device.

Nanobiotechnology is a unique class of multiphase and recently become a branch of contemporary science and a paradigm shift in material research. One of the two main problems facing the field of nanomaterial synthesis is the discovery of new natural resources for the biological production of metal nanoparticles and the absence of knowledge about the chemical composition of bio-source required for synthesis and the chemical process or mechanism behind the production of metal nanoparticles presents the second difficulty. We reported template-free green synthesized copper oxide nanoparticles using Tribulus terrestris seed natural extract without any isolation process. XRD, TEM, SEM, UV-Vis, DLS, zeta potential, and BET evaluated the synthesized metal nanoparticle. The TEM analysis confirmed that the CuO NPs are well dispersed and almost round in shape with an average size of 58 nm. EDAX confirms that copper is the prominent metal present in the nanomaterial. The greener fabricated copper oxide nanoparticle was employed to degrade methyl orange dye, almost 84% of methyl orange was degraded within 120 min. The outcomes demonstrated the nanomaterial's effective breakdown of contaminants, highlighting their potential for environmental rehabilitation. The electrochemical investigation of the CuO NPs was utilized for supercapacitor application. An appreciable value of specific capacitance is 369 F/g specific capacitances with 96.4% capacitance retention after 6000 cycles. Overall, the results of the current study show that the biologically produced copper oxide nanoparticles have intriguing uses as photocatalysts for treating water contaminants and are suitable for energy storage devices.

Lotus seedpods biochar decorated molybdenum disulfide for portable, flexible, outdoor and inexpensive sensing of hyperin.

Biomass waste, a good candidate for advanced carbon materials for sustainable electrodes, is receiving more and more attention for high value-added materials because of its promising contribution to economic growth and sustainable development. We proposed a green co-hydrothermal approach to prepare lotus seedpods biochar (BC) decorated molybdenum disulfide (MoS2) from waste lotus seedpods and precursors of MoS2, and a portable, flexible, outdoor and inexpensive sensing platform for hyperin on the integrated flexible three-electrode using U-disk potentiostat with smartphone was successfully developed. Structure and properties of MoS2-BC were characterized, it was proved that BC improves microstructure and morphology, electronic conductivity, electrode stability and electrocatalytic properties of MoS2. Attributing to these impressive features, the detection signal of hyperin was significantly amplified by the MoS2-BC modified glass carbon electrode (GCE) in detection range of 0.01-21 µΜ with detection limit (LOD) of 5 nM. It was worth mentioning that the MoS2-BC modified screen-printed electrode (SPE) performs hyperin detection in range of 100 nM - 3 µM with LOD 50 nM (S/N = 3). The practicability of the proposed method confirmed that the portable, on-site, low-cost, and outdoor detection of hyperin was feasible and practical in comparison with traditional both electrochemical sensing and HPLC methods.

Core-shell heterostructured multiwalled carbon nanotubes@reduced graphene oxide nanoribbons/chitosan, a robust nanobiocomposite for enzymatic biosensing of hydrogen peroxide and nitrite.

A robust nanobiocomposite based on core-shell heterostructured multiwalled carbon nanotubes@reduced graphene oxide nanoribbons (MWCNTs@rGONRs)/chitosan (CHIT) was described for the fabrication of sensitive, selective, reproducible and durable biosensor for hydrogen peroxide (H2O2) and nitrite (NO2-). The excellent physicochemical properties of MWCNTs@rGONRs such as, presence of abundant oxygen functionalities, higher area-normalized edge-plane structures and chemically active sites in combination with excellent biocompatibility of CHIT resulting in the versatile immobilization matrix for myoglobin (Mb). The most attractive property of MWCNTs@rGONRs which distinguishes it from other members of graphene family is its rich edge density and edge defects that are highly beneficial for constructing enzymatic biosensors. The direct electron transfer characteristics such as, redox properties, amount of immobilized active Mb, electron transfer efficiency and durability were studied. Being as good immobilization matrix, MWCNTs@rGONRs/CHIT is also an excellent signal amplifier which helped in achieving low detection limits to quantify H2O2 (1 nM) and NO2- (10 nM). The practical feasibility of the biosensor was successfully validated in contact lens cleaning solution and meat sample.

An electrochemical immunosensor for efficient detection of uropathogenic E. coli based on thionine dye immobilized chitosan/functionalized-MWCNT modified electrode.

Uropathogenic Escherichia coli (UPEC) is the major cause of 150 million Urinary Tract Infections (UTI) reported annually world-wide. High prevalence of multi-drug-resistance makes it dangerous and difficult to cure. Therefore simple, quick and early diagnostic tools are essential for effective treatment and control. We report an electrochemical immunosensor based on thionine dye (Th) immobilized on functionalized-multiwalled carbon nanotube+chitosan composite coated on glassy carbon electrode (GCE/f-MWCNT-Chit@Th) for quick and sensitive detection of UPEC in aqueous solution. This immunosensor was constructed by sequential immobilization of UPEC, bovine serum albumin, primary antibody and Horse Radish Peroxidase (HRP) tagged secondary antibody on the surface of GCE/f-MWCNT-Chit@Th. When analyzed using 2.5mM of hydrogen peroxide reduction reaction using cyclic voltammetry in phosphate buffer, pH 7.0, the immunosensor showed excellent linearity in a range of 10(2)-10(9)cfu of UPEC mL(-1) with a current sensitivity of 7.162µA {log(cfumL(-1))}(-1). The specificity of this immunosensor was tested using other UTI and non-UTI bacteria, Staphylococcus, Klebsiella, Proteus and Shigella. The clinical applicability of the immunosensor was also successfully tested directly in UPEC spiked urine samples (simulated sample).

Electrochemical redox signaling of hemoglobin in human whole blood and its relevance to anemia and thalassemia diagnosis.

A highly redox active human whole blood-carbon nanomaterial modified electrode has been developed, which showed a redox peak (vs. Ag/AgCl) similar to that of hemoglobin (vs. Ag/AgCl) in red blood cells. Clinical relevance of this for direct electrochemical analysis of blood hemoglobin content (anemia) and thalassemia disease diagnosis was demonstrated.

In Situ Derivatization of an Intrinsic Iron Impurity as a Surface-Confined Iron(II)tris(2,2'-bipyridine) Complex on MWCNT and Its Application to Selective Electrochemical Sensing of DNA's Purine Bases.

The derivatization of an intrinsic iron impurity in a carbon nanotube (CNT-*Fe, *Fe-intrinsic, and redox-active iron impurity) as a functional molecular system has been challenging to realize. There are certain limitations on the derivatization of such iron impurities such as low concentration and limited accessibility. Herein, we report an in situ electroassisted derivatization of an intrinsic and redox-active iron impurity in a multiwalled carbon nanotube (MWCNT-*Fe, *Fe, 2.1 wt %) as MWCNT-*Fe(bpy)3(2+), where Fe(bpy)3(2+) = iron(II)tris(2,2'-bipyridine) complex and bpy = 2,2'-bipyridine. The hybrid complex was prepared by the electrochemical treatment of a 2,2'-bipyridine ligand adsorbed {MWCNT-*Fe + Nafion} modified glassy carbon electrode in pH 7 phosphate buffer solution. This new MWCNT-*Fe(bpy)3(2+) hybrid electrode showed well-defined, stable redox at E1/2 = 830 mV with a peak-to-peak separation (ΔEp) of 72 mV in a neutral pH solution. This is quite different from an ex situ Nafion-Fe(bpy)3(2+) complex system that showed an unstable response at neutral pH. This in situ approach can allow the redox-active iron impurity in the CNTs to be quantified using the current signal of the Fe(bpy)3(2+) hybrid system. This MWCNT-*Fe(bpy)3(2+) hybrid modified electrode was further used as an electrochemical detector for selective and separation-less flow injection analysis of DNA's purine bases, adenine and guanine, without interference from pyrimidine bases, cytosine, and thymine at different oxidative detection potentials of 1 V (for adenine and guanine) and 0.7 V vs Ag/AgCl (for guanine) using the pH 7 phosphate buffer solution as a carrier system.

Simple electro-assisted immobilization of ciprofloxacin on carbon nanotube modified electrodes: its selective hydrogen peroxide electrocatalysis.

Ciprofloxacin (Cf) is a synthetic fourth generation fluoroquinolone class antibiotic used for the treatment of gram-positive, gram-negative and mycobacterium species infections. Electrochemical characteristic of the Cf antibiotic on carbon nanotube modified glassy carbon electrode (GCE/CNT) in pH 7 phosphate buffer solution has been investigated. Electrochemically oxidized radical byproduct of the Cf drug, which is formed as intermediate, gets immobilized on the GCE/CNT (GCE/Cf@CNT) and showed stable and well defined surface confined redox peak at -0.220 V versus Ag/AgCl. Control electrochemical experiment with unmodified GCE failed to show any such immobilization and redox features. Physicochemical characterizations of the Cf@CNT by transmission electron microscope, scanning electron microscope, infrared spectroscopy, UV-Vis and gas chromatography coupled mass spectroscopic analyses of Cf@CNT collectively revealed presence of native form of the Cf antibiotic molecule onto the CNT. The interaction between the Cf molecule and the CNT tubes are revealed from the decreased intensity in the Raman spectrum. The GCE/Cf@CNT showed excellent electrocatalytic response to hydrogen peroxide reduction reaction in pH 7 phosphate buffer solution. Amperometric i-t analysis for the detection of H2O2 showed a current linearity plot upto [H2O2] = 200 µM at an applied potential - 0.1 V versus Ag/AgCl with a current sensitivity value 678 µA mM(-1) cm(-2). No interferences were noticed with ascorbic acid, uric acid, cysteine and nitrite. The present study can be highly helpful to understand the interaction between the Cf and H2O2 in physiological systems and for the removal of Cf from the antibiotic polluted water samples especially in the aquaculture and agricultural systems.

An iron impurity in multiwalled carbon nanotube complexes with chitosan that biomimics the heme-peroxidase function.

A new biomimetic functional system having an impure multiwalled carbon nanotube (MWCNT-Fe)-chitosan biopolymer (H2N-CHIT) chemically modified glassy carbon electrode (GCE/[MWCNT-Fe:H2N-CHIT]) has been developed and demonstrated efficient hydrogen peroxide electrocatalytic and electrochemical sensing applications in pH 7 phosphate buffer solution (PBS). The hybrid system showed a stable and well-defined surface confined redox peak at an apparent electrode potential, E°'=-0.22 V versus Ag/AgCl with surface excess value 13.63 nmol cm(-2). Physicochemical characterizations of the hybrid by using FESEM, TEM, Raman spectroscopy, FTIR, and various control electrochemical experiments revealed that the iron impurity in the MWCNT interacted with the amino functional group of the chitosan polymer and thereby formed an unique complex-like structure ([MWCNT-Fe(III/II):NH2-CHIT]), similar to heme peroxidase with a central Fe(III/II)-redox-active site. The biomimetic system followed Michaelis-Menten-type reaction kinetics for the H2O2 reduction reaction with a K(M) value of 0.23 mM. At pH 7, amperometric i-t sensing and flow-injection analysis of H2O2 on the biomimetic system showed calibration plots in windows 5-500 and 50-2500 µM, with detection-limit values of 2.3 and 9.7 µM, respectively. Unlike most of the previously reported systems that undergo serious interferences in physiological pH, the biomimetic system displayed a remarkable tolerance to other co-existing interferants (such as cysteine, ascorbic acid, uric acid, nitrate, and nitrite), at a H2O2 detection potential similar to the peroxidase enzyme. The ability of the biosensor system to perform routine analyses was demonstrated by the detection of H2O2 present in simulated milk and clinical and cosmetic samples with appreciable recovery values.

Unusual neutral pH assisted electrochemical polymerization of aniline on a MWCNT modified electrode and its enhanced electro-analytical features.

Unusual electropolymerization of aniline to polyaniline (PANI) in a neutral pH solution has been successfully demonstrated using a multiwalled carbon nanotube (MWCNT) modified gold electrode (Au-MWCNT@PANIpH7). The modified electrode showed highly redox active surface confined peaks corresponding to the molecular transitions of leucoemeraldine-emeraldine and emeraldine-pernigraniline in pH 7 phosphate buffered solution (PBS), along with a low capacitance behavior, in contrast to the conventional acidic solution PANI systems. Control experiments in the absence of MWCNTs (i.e., Au/PANIpH7) and in an acidic medium, pH 2 (i.e., Au-MWCNT@PANIpH2), resulted in nil and poor redox features respectively. The physicochemical characterization of the MWCNT@PANIpH7 film by TEM, Raman spectroscopy, FTIR and UV-Vis revealed the presence of polaron type PANI structures on the MWCNT surface. More interestingly, MWCNT@PANIpH7 showed a highly selective electrocatalytic signal to ascorbic acid (AA) at a low oxidation potential, -15 mV vs. Ag/AgCl, without interference from nitrite, uric acid, dopamine, glucose, cysteine and citric acid in pH 7 PBS. Extended flow injection analysis yielded an excellent AA sensing response with a detection limit (signal-to-noise ratio = 3) of 42 nM, which is better than that of the conventional acid assisted MWCNT@PANIpH2 and MWCNT systems.

Electrochemical conversion of unreactive pyrene to highly redox-active 1,2-quinone derivatives on a carbon nanotube-modified gold electrode surface and its selective hydrogen peroxide sensing.

Pyrene (PYR) is a rigid, carcinogenic, unreactive, and nonelectrooxidizable compound. A multiwalled carbon nanotube (MWCNT)-modified gold electrode surface-bound electrochemical oxidation of PYR to a highly redox-active surface-confined quinone derivative (PYRO) at an applied potential of 1 V versus Ag/AgCl in pH 7 phosphate buffer solution has been demonstrated in this work. Among various carbon nanomaterials examined, the pristine MWCNT-modified gold electrode showed effective electrochemical oxidation of the PYR. The MWCNT's graphite impurity promotes the electrochemical oxidation reaction. Physicochemical and electrochemical characterizations of MWCNT@PYRO by Raman spectroscopy, FT-IR, X-ray photoelectron spectroscopy, and GC-MS reveal the presence of PYRO as pyrene-tetrone within the modified electrode. The quinone position of PYRO was identified as ortho-directing by an elegantly designed ortho-isomer-selective complexation reaction with copper ion as an MWCNT@PYRO-Cu(2+/1+)-modified electrode. Finally, a cytochrome c enzyme-modified Au/MWCNT@PYRO (i.e., Au/MWCNT@PYRO-Cyt c) was also developed and further demonstrated for the selective biosensing of hydrogen peroxide.

Selective electrochemical recognition of the α-naphthol isomer and in situ immobilization of naphthoquinones for tunable electrocatalysis.

Fits like a glove: Separationless and selective electrochemical oxidation of the α-naphthol (α-NAP) isomer yields naphthoquinone species on the surface of multiwalled carbon nanotubes, which can further catalyze the electro-oxidation of NADH and hydrazine at different potentials. The ß-NAP isomer failed to show any such electro-oxidation.

Facile electrochemical oxidation of polyaromatic hydrocarbons to surface-confined redox-active quinone species on a multiwalled carbon nanotube surface.

Polyaromatic hydrocarbon (PAH) oxidation: PAHs, which are considered major environmental pollutants, are carcinogenic, and cannot be electrochemically oxidized on conventional electrodes (gold, platinum, and glassy carbon), can be electrochemically oxidized on multiwalled carbon nanotube surfaces at a potential of 1 V versus Ag/AgCl at pH 7. This results in the formation of stable surface-confined quinone systems (see scheme; AN = anthracene; AQ = anthraquinone).

Room temperature aerobic oxidation of amines by a nanocrystalline ruthenium oxide pyrochlore nafion composite catalyst.

The aerobic oxidation of primary amines to their respective nitriles has been carried out at room temperature using a highly reusable nanocrystalline ruthenium oxide pyrochlore Nafion composite catalyst (see figure).

Electrochemical-assisted encapsulation of catechol on a multiwalled carbon nanotube modified electrode.

Electrochemical-assisted encapsulation of a neurotransmitter, catechol (CA), as nanoaggregates on a multiwalled carbon nanotube (>90% of carbon basis MWNT) modified gold electrode (Au/CA@CNT) has been demonstrated without any derivatization or electrode preactivation procedures. Characterization of the CA@CNT by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared attenuated total reflection (FTIR/ATR) spectroscopy, and cyclic voltammetry (CV) collectively revealed stable encapsulation of the CA within strained and misalignment areas of the MWNT capsule. The Au/CA@CNT shows a couple of redox peaks centered at 0 (A1/C1) and 200 mV vs Ag/AgCl (A2/C2) due to the encapsulated (chemisorbed) and physisorbed CA moieties, respectively. The calculated chemisorbed catechol surface excess, Gamma(CA), value was 98.3 x 10(-10) mol x cm(-2). Control solution phase preparations of CA@CNTs yielded poor loading and instability problems, if it is chemically modified on the gold electrode. Electrochemical mediated oxidation of hydrazine on the Au/CA@CNT was demonstrated with an approximately 20 times increase in peak current and 200 mV reduction in the overpotential values in a pH 7 phosphate buffer solution.

Chemically modified electrode with a film of nano ruthenium oxides stabilizing high valent RuO(4)(-) species and its redox-selective sequential transformation to polynuclear ruthenium oxide-metallocyanates.

High-valent Ru(VII)O(4)(-) (perruthenate) is a short-lived species in aqueous solutions (pH 1-14) and has scarcely been studied through electrochemistry. By a potential-controlled oxidative deposition method at 1 V vs Ag/AgCl using RuCl(3) in a pH 2 KCl-HCl buffer solution, chemically modified glassy carbon (GCE) and indium tin oxide (ITO) electrodes were successfully prepared with a film of hydrous nano ruthenium oxides RuO(2) and RuO(3), stabilizing the high-valent perruthenate anion (Ru(VII)-RuO(x)-CME, x = 2 and 3, CME = chemically modified electrode). The electrodes showed three distinct redox peaks corresponding to Ru(2)O(3)/RuO(2), RuO(2)/RuO(3), and RuO(4)(2-)/RuO(4)(-) redox processes at pH 2, like the classical RuO(2) electrodes in alkaline conditions. Solid state UV-visible spectra of the ITO/Ru(VII)-RuO(x)-CME showed characteristic absorption very close to chemically generated authentic RuO(4)(-) species in alkaline solution. Further, redox-controlled sequential procedures yielded polynuclear ruthenium oxide-hexacyanometallate films (RuO-MCN-CME, M = Fe and Ru), in which Ru(VII)-RuO(x)-CME acted as a specific template. A controlled-potential activation (>1 V) of Ru(VII)-RuO(x)-CME, stabilizing the key RuO(4)(-) species, in a solution of [Fe(CN)(6)](3-) or [Ru(CN)(6)](4-), should be a critical step for the formation of polynuclear RuO-MCN matrix.

Determination of tranexamic acid in cosmetic products by high-performance liquid chromatography coupled with barrel plating nickel electrode.

Tranexamic acid (TA) is an important reagent in cosmetic skin-whitening formulation and a drug for the inhibition of plasminogen to plasmin in blood. Since there is no chromophore in tranexamic acid molecule to enable direct analysis by UV-visible absorption spectrophotometry, derivatization is thus required by excluding use of UV or fluorescence detection. We report here a relatively simple electrochemical TA detection method by using a barrel plating nickel electrode. Chromatographic separation was performed on a Hamilton PRP-X100 anion-exchange column (150 mm x 4.1 mm i.d., 10 microm particle size) with a (85:15, v/v) mixture of 0.1 mol l(-1) NaOH and acetonitrile as mobile phase and pumped at a flow rate of 0.9 ml min(-1). By detecting at +0.55 V vs. Ag/AgCl, the calibration plot was linear in the concentration window of 3-1000 ppm with regression coefficient and detection limit (S/N=3) of 0.9993 and 0.13 ppm (0.84 micromol l(-1)), respectively. Successive injections (n=10) of 50 ppm tranexamic acid showed a R.S.D. value of only 0.3% indicating good reproducibility of the proposed system. The method was successfully applied to the analysis of the content of tranexamic acid in cosmetic products and proved to be suitable for rapid and reliable quality control.

In situ nanostructure formation of (micro-hydroxo)bis(micro-carboxylato) diruthenium units in nafion membrane and its utilization for selective reduction of nitrosonium ion in aqueous medium.

Nanostructured molecular film containing the (micro-hydroxo)bis(micro-carboxylato) diruthenium(III) units, [RuIII2(micro-OH)(micro-CH3COO)2(HBpz3)2]+ ({RuIII2(micro-OH)}), was prepared by an in situ conversion of its micro-oxo precursor, [RuIII2(micro-O)(micro-CH3COO)2(HBpz3)2] ({RuIII2(micro-O)}), in a Nafion membrane matrix, where HBpz3 is hydrotris(1-pyrazolyl)borate. The conversion procedure results in fine nanoparticle aggregates of the {RuIII2(micro-OH)} units in the Nafion membrane (Nf-{RuIII2(micro-OH)}), where an average particle size (4.1 +/- 2.3 nm) is close to the Nafion's cluster dimension of approximately 4 nm. Chemically modified electrodes by using the Nafion molecular membrane films (Nf-{RuIII2(micro-OH)}-MMFEs) were further developed on ITO/glass and glassy carbon electrode (GCE) surfaces, and a selective reduction of nitrosonium ion (NO+), presumably through reaction of a {RuIIRuIII(micro-OH)} mixed-valence state with HNO2, was demonstrated without interference by molecular oxygen in an acidic aqueous solution. The Nf-{RuIII2(micro-OH)}-MMFEs are stable even in a physiological condition (pH 7), where the naked {RuIII2(-OH)} complex is readily transformed into its deprotonated {RuIII2(micro-O)} form, demonstrating an unusual stabilizing effects for the {RuIII2(micro-OH)} unit by the Nafion cluster environment.

An electrochemical cell coupled with disposable screen-printed electrodes for use in flow injection analysis.

An electrochemical cell coupled with disposable screen-printed electrodes (SPEs) that is specifically designed for use in flow injection analysis (FIA) is described in this study. The cell is made of foldable polyoxymethylene (acetal) thick platelets with the bottom portion consisting of a cavity track to drag the SPEs in position and the top portion having predrilled T-like holes to arrange the Ag/AgCl reference electrode and stainless steel inlet & outlet. An "O ring" is suitably fixed on the top of the working electrode to form a thin-layer space where the electrochemical reaction can take place. Hydrodynamic characterization was validated by using a benchmark hexacyanoferrate redox couple. The results of practical analysis of glucose in human plasma clearly demonstrate the characteristics and applicability of the proposed wall-jet electrochemical cell in FIA.