Design,Synthesis and Biological Evaluation of Novel N‐(4‐([2,2′:5′,2′′‐Terthiophen]‐5‐yl)‐2‐methylbut‐3‐yn‐2‐yl) Benzamide Derivatives

On the basis of the principle of combination of active groups, a series of novel N‐(4‐([2,2′:5′,2′′‐terthiophen]‐5‐yl)‐2‐methylbut‐3‐yn‐2‐yl) benzamide derivatives were designed, synthesized and systematically evaluated for their antiviral activity against tobacco mosaic virus (TMV). The bioassay results showed that most of these compounds displayed good anti‐TMV activity, and some of them exhibited higher antiviral activity than commercial Ningnanmycin. Especially, compound 8e with excellent anti‐TMV activity (inactivation activity, 92.3%/500 µg·mL^?1; curative activity, 85.7%/500 µg·mL^?1 and protection activity, 64.7%/500 µg·mL^?1) emerged as a potential inhibitor of plant virus TMV. Quantitative structure‐activity relationship studies proved that the van der Waals volume (V) and electronic parameter (∑(∑σ_o+σ_p) and ∑σ_m) for the substituent R¹ were very important for antiviral activities in this class of compounds.     

Synthesis,Bioactivities and Structure Activity Relationship of N‐4‐Methyl‐1,2,3‐thiadiazole‐5‐carbonyl‐N′‐phenyl Ureas

Twenty nine novel N‐4‐methyl‐1,2,3‐thiadiazole‐5‐carbonyl‐N′‐phenyl ureas were designed and synthesized, and their structures were confirmed by proton nuclear magnetic resonance (¹H NMR), infra red spectroscopy (IR) and high‐resolution mass spectroscopy (HRMS). Compounds V‐9 , V‐11 , V‐12 , V‐15 , V‐19 , V‐21 , V‐22 and V‐24 exhibit excellent activity against Culex pipiens pallens. Compounds V‐12 and V‐22 present good insecticidal activity against Plutella xylostella L. Their median lethal concentrations (LC₅₀) are 164.15 and 89.69 mg·L^?1, respectively. Compound V‐11 also has potential wide spectrum of fungicide activity. Its median effective concentrations (EC₅₀) detected from 3.82 µg·mL^?1 against Physalospora piricola to 31.60 µg·mL^?1 against Cercospora arachidicola. Compounds V‐15 and V‐24 show outstanding induction activities as same as positive controls TDL and ningnanmycin, furthermore V‐24 has the highest induction activity of 41.85%±4.43%. To elucidate the structure activity relationship in these compounds, a 3D‐QSAR model has been built. The established model showed a reliable predicting ability with q² values of 0.643 and r² values of 0.982.     

A New Amperometric Biosensor Based on HRP/Nano-Au/L-Cysteine/Poly（o-Aminobenzoic acid）-Membrane-Modified Platinum Electrode for the Determination of Hydrogen Peroxide

The third generation amperometric biosensor for the determination of hydrogen peroxide （H2O2） has been described. For the fabrication of biosensor, o-aminobenzoic acid （oABA） was first electropolymerized on the surface of platinum （Pt） electrode as an electrostatic repulsion layer to reject interferences. Horseradish peroxidase （HRP） absorbed by nano-scaled particulate gold （nano-Au） was immobilized on the electrode modified with polymerized o-aminobenzoic acid （poABA） with L-cysteine as a linker to prepare a biosensor for the detection of H2O2. Amperometric detection of H2O2 was realized at a potential of ＋20 mV versus SCE. The resulting biosensor exhibited fast response, excellent reproducibility and sensibility, expanded linear range and low interferences. Temperature and pH dependence and stability of the sensor were investigated. The optimal sensor gave a linear response in the range of 2.99×10^-6 to 3.55×10^-3 mol·L^-1 to H2O2 with a sensibility of 0.0177 A·L^-1·mol^-1 and a detection limit （S/N = 3） of 4.3×10^-7 mol·L^-1. The biosensor demonstrated a 95% response within less than 10 s.     

Determination of Gallic Acid by Flow Injection Analysis Based on Luminol‐AgNO3‐Ag NPs Chemiluminescence System

A novel flow injection procedure has been developed for the determination of gallic acid based on the enhancement function for luminol‐AgNO₃‐Ag NPs chemiluminescence (CL) system by gallic acid. The enhancement mechanism was proposed for the reinforcing effect of the gallic acid on the CL system. The UV‐vis absorption spectrum and CL emission spectrum were applied to confirm the mechanism. The method is simple, rapid and sensitive with a detection limit of 5×10^?10 g·mL^?1 and a linear range of 8.0×10^?10–1.0×10^?7 g·mL^?1. The relative standard deviation (RSD) is 1.3% for eleven measurements of 5×10^?8 g·mL^?1 gallic acid. The method has been successfully applied to the determination of gallic acid in Chinese proprietary medicine–Jianmin Yanhou tablets and synthesized samples.     

N‐(Substituted benzyl)‐3,5‐bis(benzylidene)‐4‐piperidones: Synthesis and Preliminary Anti‐leukemia Activity (I)

A series of novel N‐(substituted benzyl)‐3,5‐bis(benzylidene)‐4‐piperidones 5a – 5o were synthesized with substituted benzylamines as raw materials via a series of Michael addition, Dieckmann condensation, hydrolysis decarboxylation and aldol condensation. The structures were confirmed by ¹H NMR, IR, MS techniques and elemental analysis. Assay‐based antiproliferative activity study using leukemic cell lines K562 revealed that most of the title compounds have high effectiveness in inhibiting leukemia K562 cells proliferation, among which the compounds 5g (IC₅₀=7.81 µg·mL⁻¹), 5k (IC₅₀=6.35 µg·mL⁻¹), 5l (IC₅₀=7.20 µg·mL⁻¹), and 5o (IC₅₀=5.79 µg·mL⁻¹) have better inhibition activities than standard 5‐fluorouracil (IC₅₀=8.56 µg·mL⁻¹).     

Trace Determination of Manganese in Urine by Graphite Furnace Atomic Absorption Spectrometry and Inductively Coupled Plasma–Mass Spectrometry

This paper describes a simple and sensitive method for the determination of manganese in human urine by graphite furnace atomic absorption spectroscopy (GFAAS), which includes sample preparation by microwave digestion. Matrix modifier combinations, the digestion power, pyrolysis, and atomization temperatures were optimized. A mixture of 5.0 µg Pd(NO₃)₂ and 3.2 µg Mg(NO₃)₂ modifier presented the best performance. The optimal temperatures for pyrolysis and atomization were 1500°C and 1950°C, respectively. The GFAAS method was compared to inductively coupled plasma–mass spectrometry (ICP–MS) for the determination of manganese in urine. Analytical figures of merit for GFAAS and ICP–MS were: accuracy (3.46%, 2.19%), precision (3.61%, 5.84%), LOD (0.109 µg · L^?1, 0.015 µg · L^?1), LOQ (0.327 µg · L^?1, 0.045 µg · L^?1), and recovery (80–100%, 74–89%). Both methods were employed for the determination of Mn in urine and the results were compared statistically.     

A Highly Selective and Sensitive Fluorescent Probe Recognition for Co2+ in Aqueous Media Based on 8‐Hydroxyquinolin‐2‐carbaldehyde‐2‐pyridylformylhydrazone Derivative

A new (8‐hydroxyquinolin‐2‐yl)methylene picolinohydrazide derivative ( L ) has been successfully synthesized and characterized. The probe L displays high selectivity to Co²⁺ in CH₃CN/HEPES (1:1, Ｖ/Ｖ, 10 mmol·L^?1, pH=7.4) with a fluorescence "ON‐OFF" response. The Co²⁺ ion recognition event possesses some distinct features including rapid response, high selectivity and sensitivity, good anti‐interference ability and being applicable within a wide pH range. Based on job's plot and ESI‐MS studies, the 1:1 binding mode was proposed. The binding constant of L and Co²⁺ is 1.63×10⁸ L·mol^?1 and the detection limit is 1.15 µmol·L^?1. Natural water samples experiments revealed that probe L can be potentially applied to the detection of Co²⁺ in real environment.     

HPLC法拆分(-)-2(S)-苄基-4-酮-4-(顺式-全氢化异吲哚-2-基)丁酸钙对映体

目的：建立刺激胰岛素分泌的新型降糖药物(-)-2 (S)-苄基-4-酮-4-(顺式-全氢化异吲哚-2-基)丁酸钙对映体的HPLC拆分方法。方法：采用Sumichiral OA-3300手性柱(250 × 4.6 mm I.D., 5 μm), 柱温35℃,以0.05 mol·L-1醋酸铵的甲醇溶液为流动相,检测波长为210 nm。结果：本品两对映体在22分钟内实现良好分离,分离度达3以上,S－异构体分别在0.028 ~ 5.6 μg mL-1和0.03 ~ 6.0 μg mL-1范围内线性关系良好,回归方程分别为：Y=1.32×103x-2.54 (r=0.9997)和Y=1.15×103x-1.78 (r=0.9998),最低检测限分别为0.15 ng和0.10 ng,方法精密度RSD低于1.0% (n=5)。结论：建立的对映体分离方法可用于本品光学异构体的质量控制。     

Ultrasensitive immunoassay of microcystins-LR using G-quadruplex DNAzyme as an electrocatalyst

An electrochemical immunoassay for microcystin-LR (MC-LR) detection was developed using multi-labeled horseradish peroxidase-mimicking DNAzyme on carbon nanotubes (CNTs) as electrocatalyst for signal amplification. CNTs were covalently conjugated to multiple DNAzyme along with MC-LR for a competitive immunoassay. The as-prepared DNAzyme/CNTs/MC-LR biolabel was specifically captured on the electrode surface, and current responses were obtained upon the electro-catalytic reduction of hydrogen peroxide by the captured biolabels. Under optimal conditions, the electro-catalytic current decreased linearly with the increase amount of MC-LR in the range from 0.01 to 7.0 µg L^?1. The linear regression equation was I (µA) = 12.96 ? 1.48 X _[MC–LR] (µg L^?1), with a correlation coefficient of 0.989. The limit of detection of MC-LR was 2.31 ng L^?1. Application of the immunoassay method and LC/MS/MS method for MC-LR determination on spiked reservoir water gave recovery range of 91.7–105.2% and 94.0–105.0%, respectively. The resulting versatile immunoassay exhibited high sensitivity, good precision and satisfactory reproducibility, which could have vast potential in routine water quality monitoring for various environmental toxins.     

Evaluation of the Counter Ions in Doped Porous Polyaniline Coatings on Stainless Steel Wires for Solid Phase Microextraction of Chlorophenolics in Water Combined with High-Performance Liquid Chromatography

Porous polyaniline coatings doped with different counter ions were electrodeposited on the surface of stainless steel wires using controlled potentiostatic coulometry. Prior to electropolymerization, the stainless steel wires were chemically etched to improve subsequent immobilization of the polyaniline coatings on the substrate and to increase the effective surface area. Porous polyaniline coatings doped with sulfate, nitrate, and perchlorate counter ions were employed for solid-phase microextraction (SPME) of 2-chlorophenol, 2,4-dichlorophenol, triclosan, and 2,4-dichlorophenoxyacetic acid coupled to high-performance liquid chromatography. The results demonstrated that the perchlorate doped polyaniline coating exhibited the highest extraction efficiency for 2-chlorophenol, 2,4-dichlorophenol, and triclosan at pH 5.0, indicating that the extraction capability was modified by introducing different counter ions into the coatings. As a result, the perchlorate doped polyaniline coated fiber was further used for the optimization of extraction condition s . The method provided linear dynamic ranges over 2 to 4 orders of magnitude. The limits of detection were 0.006 µg · L^?1, 0.005 µg · L^?1, and 0.040 µg · L^?1 for 2-chlorophenol, 2,4-dichlorophenol, and triclosan, respectively. The precision expressed as the relative standard deviation ranged from 2.20% to 5.04% for spiked water at 10 µg · L ^?1 (n = 5) and the fiber to fiber reproducibility was between 3.27% and 5.91% (n = 5). The method was successfully applied to the determination of chlorophenolics in real water samples. The recoveries of chlorophenolics in spiked water at 5.0 µg · L^?1 were between 99.60% and 108.7% with relative standard deviations between 3.24% and 5.47%.     

Study of Spectrophotometric Characteristics of the Charge Transfer Reaction of Aminomethylbenzoic Acid with 7,7,8,8‐Tetracyanoquinodimethane

A new spectrophotometric method was developed for the determination of aminomethylbenzoic acid (PAMBA) using 7,7,8,8‐tetracyanoquinodimethane (TCNQ). The method was based on the formation of charge transfer (CT) complex of this drug as n‐electron donor with the π‐acceptor TCNQ. TCNQ was found to react with PAMBA to produce a kind of yellow complex. The CT reaction proceeded quantitatively in pH 8.5 buffer solution. Different variables affecting the reaction were carefully studied and optimized. Under optimal reaction conditions, the stoichiometric ratio of the reaction, maximum absorption wavelength and the value of molar absorptivity were measured to be 1:1, 425 nm, and 1.9×10⁴ L·mol^?1·cm^?1, respectively. Beer′s law was obeyed in the range of 1–9 µg·mL^?1 of PAMBA. The data have been filled to a linear regression equation A=?0.2612+0.1123c (µg·mL^?1), with a correlation coefficient of 0.9996. The detection limit was 0.4 µg·mL^?1, R.S.D. was less than 1.9%, and average recovery was over 97.6%. The formation of the CT complex was also confirmed by both infrared and ¹H NMR measurements. The thermodynamic property, kinetic property and reaction mechanism have also been discussed. The method developed was applied successfully to the determination of the subject drug in its pharmaceutical dosage forms with good precision and accuracy compared to official method revealed by t‐ and F‐tests.     

Voltammetric Determination of 4‐Nitrophenol and 5‐Nitrobenzimidazole Using Different Types of Silver Solid Amalgam Electrodes – A Comparative Study

The voltammetric behavior of two genotoxic nitro compounds (4‐nitrophenol and 5‐nitrobenzimidazole) has been investigated using direct current voltammetry (DCV) and differential pulse voltammetry (DPV) at a polished silver solid amalgam electrode (p‐AgSAE), a mercury meniscus modified silver solid amalgam electrode (m‐AgSAE), and a mercury film modified silver solid amalgam electrode (MF‐AgSAE). The optimum conditions have been evaluated for their determination in Britton‐Robinson buffer solutions. The limit of quantification (L_Q) for 5‐nitrobenzimidazole at p‐AgSAE was 0.77 µmol L^?1 (DCV) and 0.47 µmol L^?1 (DPV), at m‐AgSAE it was 0.32 µmol L^?1 (DCV) and 0.16 µmol L^?1 (DPV), and at MF‐AgSAE it was 0.97 µmol L^?1 (DCV) and 0.70 µmol L^?1 (DPV). For 4‐nitrophenol at p‐AgSAE, L_Q was 0.37 µmol L^?1 (DCV) and 0.32 µmol L^?1 (DPV), at m‐AgSAE it was 0.14 µmol L^?1 (DCV) and 0.1 µmol L^?1 (DPV), and at MF‐AgSAE, it was 0.87 µmol L^?1 (DCV) and 0.37 µmol L^?1 (DPV). Thorough comparative studies have shown that m‐AgSAE is the best sensor for voltammetric determination of the two model genotoxic compounds because it gives the lowest L_Q, is easier to prepare, and its surface can be easily renewed both chemically (by new amalgamation) and/or electrochemically (by imposition of cleaning pulses). The practical applicability of the newly developed methods was verified on model samples of drinking water.     

Determination of Estrogens in Water Samples by Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction Combined with High Performance Liquid Chromatography

Using 1-hexyl-3-methylimidazolium hexafluorophosphate ([C₆MIM][PF₆]) ionic liquid as extraction solvent, five estrogens including estrone (E₁), 17β-estradiol (E₂), estriol (E₃), 17α -ethynylestradiol (EE₂), and diethylstilbestrol (DES) in water samples were determined by dispersive liquid-liquid microextraction (DLLME) followed by high performance liquid chromatography with a photodiode array detector and a fluorescence detector (HPLC-DAD-FLD). The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of [C₆MIM][PF₆] dispersed entirely into the sample solution with the help of a disperser solvent (acetone). Parameters including both extraction and disperser solvents and their volumes, extraction and centrifugal time, sample pH, and salt effect were investigated and optimized. Under the optimized conditions, 110–349 fold enrichment factors of analytes were obtained. The calibration curves were linear in the concentration range of 0.2–100 µg L^?1 for E₂, E₃, and EE₂ detected with FLD, and 1–100 µg L^?1 for E₁ and DES detected with DAD. The correlation coefficient of the calibration curve was between 0.9990 and 0.9997. The limits of detection (LOD, S/N = 3) for the five estrogens were in the range of 0.08–0.5 µg L^?1. The relative standard deviations (RSD) for six replication experiments at the concentration of 5.0 µg L^?1 were ≤5.7%. The proposed method was applied to the analysis of three water samples from different sources (river water, waste water, and sea water). The relative recoveries of spiked water samples are satisfied with 89.3–102.4% and 88.7–105.2% at two different concentration levels of 5.0 and 50.0 µg L^?1, respectively.     

银（III）配合物-鲁米诺流动注射化学发光新体系测定肾上腺素

儿茶酚胺是一类非常重要的神经递质,在人体的心血管系统、神经系统、内分泌腺、肾脏、平滑肌等组织系统的生理活动中起着广泛的调节作用。肾上腺素为儿茶酚胺的一种,建立灵敏、高效的肾上腺素检测技术具有重要的临床意义。本文将银（Ⅲ）配合物与鲁米诺组成新的流动注射化学发光体系,利用碱性介质中肾上腺素对三价银配合物－鲁米诺化学发光体系有明显的增强效应来测定肾上腺素的含量,并据此建立了高效测定肾上腺素的流动注射化学发光新方法。在优化的条件下,该方法测定肾上腺素的线型范围为1.0×10－9～1.0×10－7 mol L-1,检出限为8.0×10－10 mol L-1,对1.5×10－8 mol L-1肾上腺素11次平行测定,其相对标偏差为2.9％。利用建立的分析方法测定了药物肾上腺素,并对三价银－鲁米诺化学发光新体系测定肾上腺素的反应机理进行了讨论。     

Determination of Amantadine Residue in Honey by Solid‐phase Extraction and High‐performance Liquid Chromatography with Pre‐column Derivatization and Fluorometric Detection

Amantadine (AMA) is an anti‐viral drug used in apiculture to protect honeybee against the sacbrood virus (Morator aetatulae). This study described a reliable high‐performance liquid chromatographic (HPLC) method for analyzing AMA in honey using a solid‐phase extraction (SPE) cartridge (Plexa PCX) for purification, 4‐fluoro‐7‐nitro‐2,1,3‐benzoxadiazole (NBD‐F) as a pre‐column derivatization agent, and fluorometric detection (λ_ex=470 nm, λ_em=530 nm). The chromatographic separation was performed on an XDB C18 column (150×4.6 mm i.d.) using 0.1% trifluoroacetic acid/acetonitrile (35:65,V/V) as the mobile phase at a flow rate of 1.0 mL·min⁻¹ with a run time of 20 min. Under these optimal conditions, a linear relationship was observed in the range of 0.025–1.0 µg· mL⁻¹ with a good correlation coefficient (0.998) and low limit of detection (0.0080 µg·g⁻¹), the recoveries were all above 90%, and the intra‐day and inter‐day precision (RSD) ranged from 3.4%–5.1%.     

Chemical composition and antibacterial activity of Tussilago farfara (L.) essential oil from Quebec,Canada

Abstract

The chemical composition of Tussilago farfara L. essential oil from the Saguenay-Lac-St-Jean region of Quebec, Canada was analyzed by gas chromatography–flame ionisation detector (GC-FID) and gas chromatography–mass spectrometry (GC-MS), and the antibacterial activity of the oil was tested against Escherichia coli and Staphylococcus aureus. Forty-five (45) compounds were identified from the GC profile. The main components were 1-nonene (40.1%), α-phellandrene (26.0%) and ρ-cymene (6.6%). The essential oil demonstrated antibacterial activity against E. coli (MIC₅₀ = 468 µg·mL^?1; MIC₉₀ = 6869 µg·mL^?1) and S. aureus (MIC₅₀ = 368 µg·mL^?1; MIC₉₀ = 773 µg·mL^?1). Dodecanoic acid was found to be active against both bacteria having a MIC₅₀ and MIC₉₀ of 16.4 µg·mL^?1 and 95 µg·mL^?1, respectively for E. coli and a MIC₅₀ and MIC₉₀ of 9.8 µg·mL^?1 and 27.3 µg·mL^?1, respectively for S. aureus. In addition, 1-decene and (E)-cyclodecene were also found to be active against E. coli.     

Determination of Organotin Compounds in Wine by Microwave-Assisted Extraction and High Performance Liquid Chromatography–Inductively Coupled Plasma Mass Spectrometry

A new analytical procedure for the determination of five organotin compounds in several matrix wine samples is reported. The organotin compounds were extracted by microwave-assisted extraction with n-hexane. Extraction conditions, such as volume of n-hexane required, extraction temperature, and extraction time, were investigated and optimized by an orthogonal array experimental design. The determination of organotin compounds in the final extracts was carried out by liquid chromatography–inductively coupled plasma mass spectrometry. The procedure showed limits of detection between 0.029–0.049 µg · L^?1. The linearity was in the range of 0.5 to 100 µg · L^?1. The precision expressed as relative standard deviation (RSD) was below 9.43%. The developed method was successfully employed to analyze different matrix wine samples, and some analytes were detected at the level of 0.053 to 1.14 µg · L^?1.     

Spectrophotometric Determination of Gold in Water and Ore with 2‐Carboxyl‐1‐Naphthalthiorhodanine

Abstract

This paper reports on the synthesis of a new chromogenic reagent, 2‐carboxyl‐1‐naphthalthiorhodanine (CNTR). A high sensitive, selective, and rapid method for the determination of gold based on the rapid reaction of gold with CNTR and the solid phase extraction of the colored chelate with a reversed phase polymer‐based C₁₈ cartridge was developed. In the presence of 0.05–0.5 mol L^?1 of phosphoric acid solution and emulsifier‐OP medium, CNTR reacts with gold to form a red chelate of a molar ratio 1∶3 (gold to CNTR). This chelate was enriched by the solid phase extraction with a polymer‐based C₁₈ cartridge and the retained chelate was eluted from the cartridge with dimethyl formamide (DMF). The enrichment factor of 100 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.35×10⁵ L · mol^?1 · cm^?1 at 540 nm. Beer's law is obeyed in the range of 0.01～2 µg mL^?1 in the measured solution. The relative standard deviation for 11 replicates sample of 0.5 µg L^?1 level is 2.05%. The detection limit, based on three times the standard deviation is 0.02 µg L^?1 in the original sample. This method was applied to the determination of gold in water and ore with good results.     

Analysis of Carbamazepine in Tablet and Human Serum by Sweeping‐Micellar Electrokinetic Chromatography Method

Abstract

A sensitive and simple micellar electrokinetic chromatography (MEKC) method was developed for the determination of the antiepileptic drug carbamazepine (CBZ) using a sweeping on‐line concentration method with photodiode array detection. The effect of pH, concentration of the running buffer solution, organic modifier, applied voltage and injection time on the concentration efficiency and separation was investigated. An untreated fused‐silica capillary was used (50 cm; effective length, 40 cm, 75 µm i.d.) for the analysis. The background solution (BGS) was 50 mmol · L^?1 NaH₂PO₄ (pH 3.0) containing 100 mmol · L^?1 SDS and 20% acetonitrile (5.82 ms · cm^?1) with an applied voltage of ?20 kV at 25°C. Sample introduction was performed at 0.5 psi for 90 s with diode array detection at 214 nm. For the method, the calibration curve was linear over a range of 0.5–40 µg · mL^?1 for CBZ with a correlation coefficient of 0.998. The detection limit (S/N=3∶1) of CBZ was 0.10 µg · mL^?1. About 100‐fold improvement in concentration sensitivity was achieved in terms of peak height by the sweeping method compared to conventional injection method. The sweeping‐MEKC method has been successfully applied to the analysis of CBZ in tablet and human serum.     

Application of the Bismuth Film Electrode for Catalytic Adsorptive Stripping Potentiometric Determination of Cobalt in Dimethylglyoxime‐Nitrite System

Abstract

The application of bismuth film electrodes to the determination of cobalt by constant current adsorptive stripping potentiometry with exploitation of a catalytic effect is presented. The addition of NaNO₂ to the solution containing ammonia buffer and dimethylglyoxime results in a 25‐fold enhancement of the adsorptive stripping potentiometric cobalt signal. Several key parameters of the potentiometric stripping mode were optimized, including the composition of the supporting electrolyte, the stripping current, the accumulation potential, and the accumulation time. The optimized procedure yields favorable and highly stable stripping responses with good precision (RSD=1.4% for a Co concentration of 2 µg L^?1), low detection limit (0.07 µg L^?1), and good linearity (up to 10 µg L^?1, R²=0.998) with a deposition time of 60 s and a stripping current of 10 µA. The method enables the determination of Co in the presence of high excesses of Ni or Zn.