Highly-sensitive label-free electrochemical carcinoembryonic antigen immunosensor based on a novel Au nanoparticles–graphene–chitosan nanocomposite cryogel electrode

For the first time, a simple and highly sensitive label-free electrochemical carcinoembryonic antigen (CEA) immunosensor based on a cryogel electrode has been developed and tested. The as-prepared nanocomposite combined the advantages of the graphene, AuNPs and chitosan (AuNPs–GP–CS) together with the ease of preparing a cryogel coupled to a silver deposition, to act as a redox mediator, on a Au electrode. Under the optimal conditions, the decrease of the cyclic voltammetry (CV) silver peak current was proportional to the CEA concentration over a range of from 1.0 × 10⁻⁶ to 1.0 ng mL⁻¹ with a detection limit of 2.0 × 10⁻⁷ ng mL⁻¹. This AuNPs–GP–CS cryogel electrode gave a 1.7 times higher sensitivity and 25 times lower detection limit than the non-cryogel electrode. Moreover, the proposed electrochemical immunosensor exhibited good selectivity, reproducibility and stability. When applied to analyse clinical serum samples, the data determined by the developed immunosensor were in agreement with those obtained by the current hospital analysis system (enzyme linked fluorescent assay) (P > 0.05), to indicate that the immunosensor would be potentially useful for clinical diagnostics.     

Label-free amperometric immunosensor based on prussian blue as artificial peroxidase for the detection of methamphetamine

A label-free amperometric immunosensor for the detection of methamphetamine was developed. The prussian blue deposited/l-cystine-modified electrode was covered with nano-Au/(3-mercaptorpropyl) trime-thoxysilane film. Then, the nano-Au was used for the immunosensor platform to capture a large amount of anti-methamphetamine. PB exhibited excellent electrocatalytical properties toward the reduction of H₂O₂ at low overpotentia to amplify the amperometric signal, which enhanced the sensitivity of the immunosensor. The active sites of PB could be shielded and the access of H₂O₂ from solution to the electrode might be partially blocked after the completion of immunoassay, led to a linear decrease in the response current of the electrode over the range from 1.0 × 10⁻⁸ to 5.0 × 10⁻⁶ mol L⁻¹of MA. The obtained immunosensor displayed excellent catalytic reduction toward H₂O₂ due to high activity and selectivity of PB. The influence of relevant experimental variables, including the construction of immunosensor platform, the amount of MPS and the time of immunoaction, was examined and optimized.     

Citrinin (CIT) determination in rice samples using a micro fluidic electrochemical immunosensor

The development of an electrochemical immunosensor incorporated in a micro fluidic cell for quantification of citrinin (CIT) mycotoxin in rice samples is described for the first time. Both CIT present in rice samples and immobilized on a gold surface electrodeposited on a glassy carbon (GC) electrode modified with a cysteamine self-assembled monolayer were allowed to compete for the monoclonal mouse anti-CIT IgG antibody (mAb-CIT) present in solution. Then, an excess of rabbit anti mouse IgG (H + L) labelled with the horseradish peroxidase (secAb-HRP) was added, which reacts with the mAb-CIT which is in the immuno-complex formed with the immobilized CIT on the electrode surface. The HPR, in the presence of hydrogen peroxide (H₂O₂) catalyzes the oxidation of catechol (H₂Q) whose back electrochemical reduction was detected on a GC electrode at −0.15 V vs Ag/AgCl by amperometric measurements. The current measured is proportional to the enzymatic activity and inversely proportional to the amount of CIT present in the rice samples. This immunosensor for CIT showed a range of work between 0.5 and 50 ng mL⁻¹. The detection (LOD) and the quantification (LOQ) limits were 0.1 and 0.5 ng mL⁻¹, respectively. The coefficients of variation intra- and inter-assays were less than 6%. The electrochemical detection could be done within 2 min and the assay total time was 45 min. The immunosensor was provided to undertake at least 80 determinations for different samples with a minimum previous pre-treatment. Our electrochemical immunosensor showed a higher sensitivity and reduced analysis time compared to other analytical methods such as chromatographic methods. This methodology is fast, selective and very sensitive. Thus, the immunosensor showed to be a very useful tool to determine CIT in samples of cereals, mainly rice samples.     

Electrochemical Immunosensor for Lactate Dehydrogenase Detection Through Analyte-driven Catalytic Reaction on Multi-walled Carbon Nanotubes and Gold Nanoparticle Modified Carbon Electrode

A novel electrochemical immunosensor for lactate dehydrogenase (LDH) detection was proposed based on analyte-driven catalytic reaction by attaching LDH antibodies on multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) modified glassy carbon electrodes (GCE). As LDH was captured by the antibodies on electrode surface, it catalyzed the formation of pyruvate and the reduced form of nicotinamide adenine dinucleotide (NADH), thus a sensitive electrochemical signal obtained from the above redox reaction was recorded by differential pulse voltammetry (DPV). Under optimum conditions, the developed immunosensor exhibits high sensitivity for LDH quantification ranging from 0.001 μg/mL to 0.5 μg/mL with a low detection limit at 0.39 ng/mL. This developed immunosensor reveals ideal accuracy and feasibility for LDH detection in Streptococcus uberis (S. uberis) induced bovine mammary epithelial cells (MECs) samples by comparison with conventional commercial kit, which shows remarkably application potential in diseases diagnosis.     

Label-free capacitive immunosensor based on quartz crystal Au electrode for rapid and sensitive detection of Escherichia coli O157:H7

A label-free capacitive immunosensor based on quartz crystal Au electrode was developed for rapid and sensitive detection of Escherichia coli O157:H7. The immunosensor was fabricated by immobilizing affinity-purified anti-E. coli O157:H7 antibodies onto self-assembled monolayers (SAMs) of 3-mercaptopropionic acid (MPA) on the surface of a quartz crystal Au electrode. Bacteria suspended in solution became attached to the immobilized antibodies when the immunosensor was tested in liquid samples. The change in capacitance caused by the bacteria was directly measured by an electrochemical detector. An equivalent circuit was introduced to simulate the capacitive immunosensor. The immunosensor was evaluated for E. coli O157:H7 detection in pure culture and inoculated food samples. The experimental results indicated that the capacitance change was linearly correlated with the cell concentration of E. coli O157:H7. The immunosensor was able to discriminate between cellular concentrations of 10²–10⁵ cfu mL⁻¹ and has applications in detecting pathogens in food samples. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were also employed to characterize the stepwise assembly of the immunosensor.     

A novel capacitive immunosensor based on gold colloid monolayers associated with a sol-gel matrix

A capacitive sensing method based on self-assembling gold nanoparticles to the surface of the sol-gel modified electrode has been developed for the direct detection of the human IgG in human serum. The capacitance of the immunosensor corresponding to the concentration of human IgG is investigated by alternating current impedance. The formed mercaptopropyltriethoxysilane (MPTS) film is ultrathin; the immobilization density of antibodies is high because of high surface-volume area of the assembled gold nanoparticles and the biological macromolecules when immobilized on gold nanoparticles can retain their bioactivity. This capacitive immunosensor prepared with present method can provide high sensitivity. The linear calibration curve was obtained in the range 8.3-2128 ng/ml, with a detection limit of 3.3 ng/ml when plotted versus the logarithm of the antigen concentration. After each immunoassay, the regeneration of the electrode could be performed through washing in basic solution without obvious decrease in response. No cross-reactivity was observed with other protein species. The dependence of sol-gel modified electrode stability on the pH value and ion strength was studied. The insulating properties of the different layers of the immunosensor were also investigated.     

Potentiometric Immunosensor Based on Immobilization of Hepatitis B Surface Antibody on Platinum Electrode Modified Silver Colloids and Polyvinyl Butyral as Matrixes

A highly sensitive immunosensor based on immobilization of hepatitis B surface antibody (HBsAb) on platinum electrode (Pt) modified silver colloids and polyvinyl butyral (PVB) as matrixes has been developed for potentiometric immunoanalysis to detect hepatitis B surface antigen (HBsAg) in this study. HBsAb molecules were immobilized successfully on nanometer‐sized silver colloid particles associated with polyvinyl butyral on a platinum electrode surface. The modification procedure was electrochemically monitored by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The HBsAb‐silver‐PVB‐modified electrode exhibited direct electrochemical behavior toward HBsAg. The factors influencing the performance of the resulting immunosensor were studied in detail. More than 94.7% of the results of human serum samples obtained by this method were in agreement with those obtained by enzyme‐linked immunosorbent assays (ELISAs). The resulting immunosensor exhibited a sigmoid curve with log HBsAg concentration, high sensitivity (39.8 mV/decade), wide linear range from 16.0 to 800 ng mL^?1 with a detection limit of 3.6 ng mL^?1, fast potentiometric response (<3 min) and long‐term stability (>4 months). The response mechanism of the immunosensors was also studied with AC impedance techniques.     

A novel antibody–antigen based impedimetric immunosensor for low level detection of HER2 in serum samples of breast cancer patients via modification of a gold nanoparticles decorated multiwall carbon nanotube-ionic liquid electrode

A highly sensitive impedimetric immunosensor based on a gold nanoparticles/multiwall carbon nanotube-ionic liquid electrode (AuNPs/MW-CILE) was developed for the determination of human epidermal growth factor receptor 2 (HER2). Gold nanoparticles were used to enhance the extent of immobilization and to retain the immunoactivity of the antibody Herceptin on the electrode. Cyclic voltammetry and electrochemical impedance spectroscopy were employed for characterization of various layers coated onto the AuNPs/MW-CILE. The impedance measurements at different steps were based on the charge transfer kinetics of the [Fe(CN)₆]^3−/4− redox pair. The immobilization of antibody and the corresponding antigen–antibody interaction at the electrode surface altered the interfacial electron transfer. The interactions of antibody with various concentrations of antigen were also monitored via the change of impedance response. The results showed that the charge transfer resistance increases linearly with increasing concentrations of HER2 antigen. The linear range and limit of detection were found as 10–110 ng mL⁻¹ and 7.4 ng mL⁻¹, respectively. The sensitivity and specificity of the immunosensor were validated. The results showed that the prepared immunosensor is a useful tool for screening of trace amounts of HER2 in serum samples of breast cancer patients.     

Enzyme-catalyzed silver deposition on irregular-shaped gold nanoparticles for electrochemical immunoassay of alpha-fetoprotein

A new and disposable electrochemical immunosensor was designed for detection of alpha-fetoprotein (AFP), as a model analyte, with sensitivity enhancement based on enzyme-catalyzed silver deposition onto irregular-shaped gold nanoparticles (ISGNPs). The assay was carried out with a sandwich-type immunoassay protocol by using ISGNP-labeled anti-AFP antibodies conjugated with alkaline phosphatase (ALP–Ab₂) as detection antibodies. The enzymatically catalytic deposition of silver on the electrode could be measured by stripping analysis in KCl solution due to the Ag/AgCl solid-state voltammetric process. Several labeling protocols including spherical gold nanoparticle-labeled ALP–Ab₂ and ISGNP-labeled ALP–Ab₂ were investigated for determination of AFP, and improved analytical properties were achieved with the ISGNP labeling. With the ISGNP labeling method, the effects of incubation time and incubation temperature for antigen-antibody reaction, and deposition time of silver on the current responses of the electrochemical immunosensors were also monitored. Under optimal conditions, the electrochemical immunosensor exhibited a wide dynamic range from 0.01 ng mL⁻¹ to 200 ng mL⁻¹ with a detection limit of 5.0 pg mL⁻¹ AFP. The immunosensor displayed a good stability and acceptable reproducibility and accuracy. No significant differences at the 95% confidence level were encountered in the analysis of 10 clinical serum samples between the developed immunoassay and the commercially available electrochemiluminescent method for determination of AFP.     

A novel piezoelectric immunosensor for detection of carcinoembryonic antigen

A simple, rapid, and highly sensitive immunosensor for the direct determination of carcinoembryonic antigen (CEA) in human serum using a piezoelectric crystal has been developed and optimized. In order to improve sensitivity of the immunosensor, a protein A-based orientation-controlled immobilization method for antibodies was adopted together with an immunoreactive accelerant of polyethyleneglycol (PEG) used to amplify the signal response of frequency. Human normal serum was utilized as a reference background. The linear range for CEA concentration obtained by the end-point method was 66.7-466.7 ng/mL. Clinical samples from cancer patients were analyzed by the proposed piezoelectric immunoassay, and the analytical results were reasonably comparable with those obtained by the chemiluminescence immunoassay (CLIA). The proposed immunosensor provides a new promising method for the highly sensitive immunoassay of CEA in clinical laboratory.     

Potentiometric multi-syringe flow injection system for determination of exchangeable potassium in soils with in-line extraction

A multi-syringe flow injection system for the potentiometric determination of exchangeable potassium in soil samples is proposed. Firstly, a manifold was devised to allow determination in soil extracts prepared off-line. It was possible to analyze samples prepared in extractants with different composition (Mehlich or Morgan) without physical or chemical modification of the manifold. A linear dynamic concentration range of 6–391 mg L^− 1 was obtained, allowing the direct introduction of soil extract without dilution. A determination frequency of 50 h^− 1 was achieved, with good repeatability for 10 consecutive injections of soil extracts (RSD < 3.0%). The in-line preparation of soil extract was implemented by automatic addition of extractant solution to a previously weighed portion of soil, followed by in-line filtration. Good repeatability was attained as the variance of the extraction procedure was not significantly different from the variance obtained in consecutive measurements of the same extract. Furthermore, results comparable to those obtained by off-line extraction and determination by flame emission spectrometry were attained for the two soil samples tested. Using this procedure, a determination frequency of 13 h^− 1 and a sampling rate of 4 h^− 1 were achieved.     

Double‐Layer Nanogold and Double‐Strand DNA‐Modified Electrode for Electrochemical Immunoassay of Cancer Antigen 15‐3

Various sensor‐based immunoassay methods have been extensively developed for the detection of cancer antigen 15‐3 (CA 15‐3), but most often exhibit low detection signals and low detection sensitivity, and are unsuitable for routine use. The aim of this work is to develop a simple and sensitive electrochemical immunoassay for CA 15‐3 in human serum by using nanogold and DNA‐modified immunosensors. Prussian blue (PB), as a good mediator, was initially electrodeposited on a gold electrode surface, then double‐layer nanogold particles and double‐strand DNA (dsDNA) with the sandwich‐type architecture were constructed on the PB‐modified surface in turn, and then anti‐CA 15‐3 antibodies were adsorbed onto the surface of nanogold particles. The double‐layer nanogold particles provided a good microenvironment for the immobilization of biomolecules. The presence of dsDNA enhanced the surface coverage of protein, and improved the sensitivity of the immunosensor. The performance and factors influencing the performance of the immunosensor were evaluated. Under optimal conditions, the proposed immunosensor exhibited a wide linear range from 1.0 to 240 ng/mL with a relatively low detection limit of 0.6 ng/mL (S/N=3) towards CA 15‐3. The stability, reproducibility and precision of the as‐prepared immunosensor were acceptable. 57 serum specimens were assayed by the developed immunosensor and standard enzyme‐linked immunosorbent assay (ELISA), respectively, and the results obtained were almost consistent. More importantly, the proposed methodology could be further developed for the immobilization of other proteins and biocompounds.     

SPME and SPE comparative study for coupling with microwave-assisted micellar extraction in the analysis of organochlorine pesticides residues in seaweed samples

Solid-phase microextraction (SPME) and solid-phase extraction (SPE) procedures were coupling with microwave-assisted micellar extraction for organochlorine pesticides residues determination in seaweed samples. They were optimized, compared and discussed.Preliminary experiments were performed in order to study experimental conditions for the extraction of pesticides from spiked seaweed samples with microwave-assisted micellar extraction (MAME) using a non-ionic surfactant (Polyoxyethylene 10 Lauryl Ether). After that, SPME and SPE were used to clean-up and preconcentrate MAME extract prior the analysis by liquid chromatography with photodiode array (PDA) detection.Excellent results were obtained for both procedures. Average pesticide recoveries between 80.5 and 104.3% for MAME-SPME and between 73.9 and 111.5% for MAME-SPE were obtained. Relative standard deviations (RSDs) were lower than 10.3% and 5.3% respectively for all recoveries tested, and LOD between 138–348 ng g^− 1 for MAME-SPME and 2–38 ng g^− 1 for MAME-SPE were obtained. The method was validated using Soxhlet extraction procedure.Both methods were applied to analyse target organochlorine pesticides in several seaweed samples and results were compared. These results show the great possibilities of combining MAME-SPE-HPLC-UV for the analysis of seaweed samples, improving the selectivity and sensitivity in the determination of organochlorine pesticides analysis for this kind of samples.     

溶胶-凝胶-HBsAb膜免疫传感器的研制与应用

采用溶胶-凝胶(Sol-gel)技术,成功地将乙肝表面抗体(HBsAb)包埋于Sol-gel中,再滴涂于铂盘电极表面,制成溶胶-凝胶-HBsAb膜非标记免疫传感器.根据抗原与抗体特异性结合形成的免疫复合物使敏感膜有效扩散截面积减小的特性,提出了利用铁氰化钾作为氧化还原探针间接检测乙肝表面抗原(HBsAg)的新方法.用循环伏安法(CV)对电极逐层修饰过程进行了表征,并探讨了对HBsAg定量检测的可行性及其响应机理.采用差示脉冲伏安法(DPV)检测人体血清中的HBsAg.线性范围5～320μg/L,线性相关系数r=0.997.该传感器响应迅速,灵敏度高,稳定性好.于4℃干态保存14d,其响应信号基本不变.将其用于108例临床血清检验,与酶联免疫吸附法(ELISA)的符合率为87.5％.     

Novel potentiometric immunosensor for determination of diphtheria antigen based on compound nanoparticles and bilayer two-dimensional sol–gel as matrices

A novel method for fabrication of a diphtheria potentiometric immunosensor has been developed by means of self-assembling compound nanoparticles to a thiol-containing sol–gel network. A cleaned gold electrode was first immersed in a 3-mercaptopropyltrimethoxysilane (MPS) sol–gel solution to assemble a silica sol–gel monolayer. The silane entities were then polymerized into a two-dimensional sol–gel network (2D network) by dipping into aqueous NaOH. The second silane layer was formed by re-immersion in the MPS sol–gel solution overnight. The compound nanoparticles (nanocompounds) containing gold nanoparticles and silver nanoparticles were then chemisorbed on to the thiol groups of the second silane layer. Finally, diphtheria antibody (anti-Diph) was adsorbed on to the surface of the compound nanoparticles. The modified process was characterized by cyclic voltammetry (CV). Detection is based on the change in the potentiometric response before and after the antigen–antibody reaction. A direct potentiometric response to diphtheria antigen (Diph) was obtained from the immobilized diphtheria antibody. The potentiometric response of the resulting immunosensor was rapid and the linear range was from 22 to 800 ng mL^–1 with the linear regression equation E=–79.5+69.4 log [Diph] and a detection limit of 3.7 ng mL^–1 (at 3). Up to 19 successive assay cycles with retention of sensitivity were achieved for probes regenerated with 0.2 mol L^–1 glycine–hydrochloric acid (Gly–HCl) buffer solution. Moreover, analytical results from several serum samples obtained using the developed technique were in satisfactory agreement with those given by the ELISA method, implying a promising alternative approach for detecting diphtheria antigen in clinical diagnosis.     

Determination of progesterone (P4) from bovine serum samples using a microfluidic immunosensor system

Progesterone (P4) is a steroidal hormone with a vital role in the maintenance of human and animal health. This paper describes the development of an immunosensor coupled to glassy carbon (GC) electrode and integrated to a microfluidic system to quantify P4 from bovine serum samples in a fast and sensitive way. The serum samples spiked with a given P4 concentration and a given P4 concentration bound to horseradish peroxide (HPR) were simultaneously added and, therefore, they competed immunologically with sheep monoclonal anti-P4 antibodies that were immobilized at a rotating disk. HRP in the presence of hydrogen peroxide (H₂O₂) catalyzes the chatecol (H₂Q) oxidation to benzoquinone (Q). Its reverse electrochemical reduction to H₂Q can be detected at a GC electrode surface at −0.15 V by chronoamperometric measurements. These current responses are proportional to the enzyme activity and inversely proportional to the P4 amount present in bovine serum samples. This P4 immunosensor showed a linear working range from 0.5 to 12.5 ng mL⁻¹. The detection (DL) and quantification (QL) limits were 0.2 and 0.5 ng mL⁻¹, respectively. The electrochemical immunosensor had a higher sensitivity than the ELISA method using conventional spectrophotometric detections. However, both methods allowed us to obtain similar detection limits. The immunosensor allowed us to make up to 100 determinations on different samples without any previous pre-treatment. This behavior proved to be suitable to detect P4 in routine veterinary, clinical, biological, physiological, and analytical assays.     

Highly conducting gold nanoparticles-graphene nanohybrid films for ultrasensitive detection of carcinoembryonic antigen

A new label-free amperometric immunosensor was developed for detection of carcinoembryonic antigen (CEA) based on chitosan-ferrocene (CS-Fc) and nano-TiO₂ (CS-Fc + TiO₂) complex film and gold nanoparticles-graphene (Au-Gra) nanohybrid. CS-Fc + TiO₂ composite membrane was first modified on a bare glass carbon electrode. Then Au-Gra nanohybrid was formed on the CS-Fc + TiO₂ membrane by self-assembly strategy. Next, further immobilization of anti-CEA was constructed according to the strong interaction between Au-Gra and the amido groups of anti-CEA. Since Au-Gra nanohybrid films provided a congenial microenvironment for the immobilization of biomolecules, the surface coverage of antibody protein could be enhanced and the sensitivity of the immunosensor has been improved. The good electronic conductive characteristic might be attributed to the synergistic effect of graphene nanosheets and Au NPs. The modified process was characterized by scanning electron microscope (SEM) and cyclic voltammetry (CV). Under optimized conditions, the resulting biosensor displayed good amperometric response to CEA with linear range from 0.01 to 80 ng/mL and a detection limit of 3.4 pg/mL (signal/noise = 3). The results demonstrated that the immunosensor has advantages of high conduction, sensitivity, and long life time. This assay approach showed a great potential in clinical applications and detection of low level proteins.     

Development of a novel label-free amperometric immunosensor for the detection of okadaic acid

Okadaic acid (OA), a lipophilic phycotoxin is mainly produced by toxigenic dinoflagellates. The need to develop high performing methods for OA analysis able to improve the traditional ones is evident. In this work, a novel experimental methodology for label-free detection of OA was developed. Protein G magnetic beads (protein-G-MBs) modified gold electrode was used to immobilize anti-OA monoclonal antibody (anti-OA-MAb). Preliminary, colorimetric tests were performed in order to validate protein-G-MBs and anti-OA-MAb reaction. Electrochemical detection was carried out by differential pulse voltammetry in ferri/ferrocyanide solution. The limit of detection value obtained (0.5 μg L⁻¹) validated the developed electrochemical immunosensor as a promising tool for routine use. The matrix effect and the recovery rate were also assessed with real samples, showing a good percentage of recovery.     

Electropolymerized film of functionalized thiadiazole on glassy carbon electrode for the simultaneous determination of ascorbic acid, dopamine and uric acid

The present study reports the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) in 0.20 M phosphate buffer solution (pH 5.0) using electropolymerized ultrathin film of 5-amino-2-mercapto-1,3,4-thiadiazole (AMT) on glassy carbon (GC) electrode. The bare GC electrode does not separate the voltammetric signals of AA, DA and UA. However, electropolymerized AMT (p-AMT) modified GC electrode not only resolved the voltammetric signals of AA, DA and UA but also dramatically enhanced their oxidation peak currents when compared to bare GC electrode. The enhanced oxidation currents for AA, DA and UA at p-AMT modified electrode are due to the electrostatic interactions between them and the polymer film. Using amperometric method, we achieved the lowest detection of 75 nM AA, 40 nM DA and 60 nM UA at p-AMT modified electrode. The amperometric current was linearly increased from 200 nM to 0.80 mM for each AA, DA and UA and the lowest detection limit was found to be 0.92, 0.07 and 0.57 nM, respectively (S/N = 3). The practical application of the modified electrode was demonstrated by the determination of DA in dopamine hydrochloride injection.     

Use of a graphite–polyurethane composite electrode for electroanalytical determination of indole-3-acetic acid in soil samples

A new electroanalytical methodology was developed for the quantification of the phytohormone indole-3-acetic acid (IAA), using a graphite–polyurethane composite electrode (GPU) and the square wave voltammetry (SWV), in 0.1 mol L^− 1 phosphoric acid solution (pH 1.6). Analytical curves were constructed under optimized conditions (f = 100 s^− 1, a = 50 mV, E_i = 5 mV) and the reached detection and quantification limits were 26 μg L^− 1 and 0.2 mg L^− 1, respectively. The developed methodology is simple and accurate for the routine determination of IAA. In order to verify the application of the electroanalytical methodology in fortified soil samples without previous treatment, an IAA assay was performed without serious interferences of the soil constituents.