Microfluidic devices obtained by thermal toner transferring on glass substrate

A new process for the manufacture of microfluidic devices based on deposition of laser-printing toner on glass substrates is described. It is an alternative method to the toner on polyester film (toner-polyester) one, previously introduced. Commercial laser printers cannot print directly on glass, thus the toner must first be printed on a special paper and then transferred by heating under pressure to the glass surface. Although this procedure is more complex than the toner-polyester one, it can be repeated several times, yielding multiple toner layers. Even without special alignment equipment, up to four layers could be satisfactorily piled up. Characterization tests revealed that the toner-glass devices have similar behavior as toner-polyester ones regarding the toner layer porosity. The main advantages of the toner-glass technology are improved mechanical stability, possibility of multiple toner layers, augmented electroosmotic flow (EOF), and improved heat transfer. On the other hand, toner adhesion to glass is weaker than to polyester, which limits the device lifetime and usable liquid media. The measured EOF mobility (3.5 x 10(-4) cm2.V(-1).s(-1) for pH 7) suggests that it is mainly determined by the glass surface, being little influenced by the toner walls. Microchip electrophoresis with contactless conductivity detection and photometric detection were implemented using toner-glass devices.     

Polyester-toner electrophoresis microchips with improved analytical performance and extended lifetime

This paper reports the fabrication of polyester-toner (PT) electrophoresis microchips with improved analytical performance and extended lifetime. This has been achieved with a better understanding about the EOF generation and the influence of some parameters including the channel dimensions (width and depth), the injection mode, and the addition of organic solvent to the running buffer. The analytical performance of the PT devices was investigated using a capacitively coupled contactless conductivity detector and inorganic cations as model analytes. The proposed devices have exhibited EOF values of (3.4 ± 0.2) × 10(-4) cm(2) V(-1) s(-1) with good stability over 25 consecutive runs. It has been found that the EOF magnitude depends on the channel dimension, i.e. the wider the channel, the higher the EOF value. The separation efficiency for inorganic cations ranged from 13 000 to 50 000 plates/m. The LOD found for K(+) , Na(+) , and Li(+) were 4.2, 7.3, and 23 μM, respectively. In addition, the same PT device has been used by three consecutive days. Lately, due to improved analytical performance, it was carried out by the first time the detection of inorganic cations in real samples such as energetic drinks and pharmaceutical formulations.     

Electrophoresis microchip fabricated by a direct-printing process with end-channel amperometric detection

We describe the development of an electrophoresis microchip fabricated by a direct-printing process, based on lamination of printed polyester films with end-channel amperometric detection. The channel structures are defined by polyester (base and cover) and by a toner layer (walls). The polyester-toner devices presented an electroosmotic flow (EOF) magnitude of approximately 10(-5) cm2 V(-1) s(-1), which is generated by a polymeric mixture of the toner and polyester composition. The microelectrodes used for detection were produced combining this laser-printer technology to compact discs. The performance of this device was evaluated by amperometric detection of iodide and ascorbate. The detection limits found were 500 nmol.L(-1) (135 amol) and 1.8 micromol.L(-1) (486 amol) for iodide and ascorbate, respectively.     

Novel floating‐type low‐energy ion gun for high‐resolution depth profiling in ultrahigh vacuum

A floating‐type low‐energy ion gun (FLIG) has been developed for high‐resolution depth profiling in ultrahigh vacuum (UHV). This UHV‐FLIG allows Ar⁺ ions of primary energy down to 50 eV to be provided with high current intensity. The developed UHV‐FLIG was sufficiently compact, being ～30 cm long, to be attached to a commercial surface analytical instrument. The performance of the UHV‐FLIG was measured by attaching it to a scanning Auger electron microprobe (JAMP‐10, Jeol), the base pressure of which in the analysis chamber was ～1 × 10^?7 Pa. The vacuum condition of ～5 × 10^?6 Pa was maintained during operation of the UHV‐FLIG without a differential pumping facility. Current density ranged from 41 to 138 µA cm^?2 for Ar⁺ ions of primary energy 100–500 eV at the working distance of 50 mm. This ensures a sputtering rate of ～10 nm h^?1 with 100 eV Ar⁺ ions for Si, leading to depth profiling of high resolution in practical use. Copyright © 2003 John Wiley & Sons, Ltd.     

Hydroxylation of the silica in microfabricated thin layer chromatography plates as probed by time‐of‐flight secondary ion mass spectrometry and diffuse reflectance infrared Fourier transform spectroscopy

Microfabricated silica thin layer chromatography (TLC) plates have previously been prepared on patterned carbon nanotube forests. The high temperatures used in their fabrication reduce the number of hydroxyl groups on their surfaces. Fortunately, silica can be rehydroxylated. In diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), a silanol peak below 3740 cm^?1 indicates a well‐hydroxylated silica surface that is fit for chromatography. Hydroxylations of our materials with HF are so effective that it is not possible to discern the position of this peak. In contrast, this signal is discernable when the plates are treated with NH₄OH. To find a more convenient method for studying the surfaces of TLC plates, time‐of‐flight secondary ion mass spectroscopy (ToF‐SIMS) was considered. ToF‐SIMS is advantageous because multiple microfabricated TLC plates must be scraped to obtain enough silica for one DRIFT analysis, while static SIMS can be performed on very small regions (500 × 500 µm² or less) of individual plates. Ratios of the SiOH⁺ and Si⁺ ToF‐SIMS signals for microfabricated TLC plates correlated well with ~3740 cm^?1 silanol peaks from DRIFT. Thus, SIMS allows direct analysis of all of our treated and untreated plates, including those hydroxylated with HF. The best hydroxylation condition for HF, which was better than any studied for NH₄OH, was around 150 ppm at room temperature. The best hydroxylation condition for NH₄OH was 50 °C for 72 h. ToF‐SIMS versus DRIFT results of commercial TLC plates were also obtained and evaluated. Copyright © 2014 John Wiley & Sons, Ltd.     

X‐Ray Photoelectron Spectroscopy and Electron Microscopy of Hydralazinium Ion‐Selective Electrode Membrane's Surface

New hydralazinium (Hz) plastic membrane electrodes of either conventional or coated‐wire type were constructed based on incorporation of Hz‐phosphotungstate (Hz‐PT) ion associate or Hz‐reineckate (Hz‐Rn) ion‐pair in poly(vinyl chloride) membranes. The (Hz‐PT)‐based electrodes required 30 minutes conditioning time to exhibit nearly Nernstian response over the concentration range 1.58×10^?5–1.7×10^?2 M HzCl. They also showed life span of 17 days, working pH range of 3.2 to 9.4 and high selectivity for Hz towards Na⁺, K⁺, Mg²⁺ and Ca²⁺. The electrodes have not lost their efficiency at temperatures elevated up to 60 °C. They were successfully employed to assaying HzCl in a pharmaceutical preparation. The electrode containing (Hz‐Rn) ion‐pair required 30 minutes conditioning time to show response for Hz over the concentration range 2.5×10^?5–5.6×10^?2 M. The life span of the electrode was only 8 h. X‐ray photoelectron spectroscopy was applied to investigate the effect of prolonged soaking on the membrane's surface of both types of electrodes. The surfaces of fresh and expired membranes containing Hz‐PT were also examined by electron microscopy. The results indicated that the limitation of the life span of plastic membrane electrodes is attributed to leaching of the ion exchanger from the membrane to the test solution in addition to deformation at the surface of the expired electrode.     

Multi‐responses Methodology Applied in the Electroanalytical Determination of Hair Dye by Using Printed Carbon Electrode Modified with Graphene

This paper describes a rapid and sensitive method for determination of the hair dye Basic Blue 41 in wastewater samples using screen‐printed carbon electrodes modified with graphene (SPCE/Gr). The method is based on the reversible reduction of azo groups of the dye at potential of ?0.23 V/?0.26 V, where both the anodic and cathodic currents increased 1,300 % when compared to screen‐printed carbon (SPCE) and glassy carbon electrodes (GCE). The optimization of a square wave voltammetric method was performed by means of 2³ factorial design, Doehlert matrix and multi‐response assays, and the best parameters were: frequency (54.8 Hz), step potential (6 mV), pulse amplitude (43.7 mV) and pH 4.5. The analytical curve was constructed from 3.00×10^?8 to 2.01×10^?6 mol L^?1, with detection and quantification limits of 5.00×10^?9 and 1.70×10^?8 mol L^?1, respectively. The repeatability of the method evaluated for 10 consecutive measurements at concentrations of 1.70×10^?7 mol L^?1 and 1.70×10^?6 mol L^?1, showed relative standard deviation of 3.56 and 0.57 %, respectively. The sensor based in SPCE/Gr was successfully applied in wastewater samples collected from a drinking water treatment plant and validated by comparison with HPLC‐DAD method with good accuracy.     

Anodic Stripping Voltammetric Determination of Aurothiomalate in Urine Using a Screen‐Printed Carbon Electrode

This work describes an electroanalytical method for determining gold(I) thiomalate, aurothiomalate, widely used for treatment of reumatoid arthiritis, using a screen‐printed carbon electrode (SPCE). Aurothiomalate (AuTM) was determined indirectly at the same electrode by accumulating it first at ?1.5 V vs. printed carbon. At this potential in the adsorbed state, the AuTM is reduced to Au(0), which is then oxidized at two steps at ?0.22 V and +0.54 V on SPCE. Using optimized conditions of 60 s deposition time, ?1.5 V (vs. printed carbon) accumulation potential, 100 mV s^?1 scan rate, linear calibration graphs can be obtained by monitoring the peak at +0.54 V for AuTM in HCl 0.1 mol L^?1 from 1.43×10^?6 to 1.55×10^?4 mol L^?1. A limit of detection obtained was 6.50×10^?7 mol L^?1, and the relative standard deviation from five measurements of 3.0×10^?5 mol L^?1 AuTM is 4.5%. The method was successfully applied for AuTM determination in human urine sample.     

Fabrication and integration of planar electrodes for contactless conductivity detection on polyester-toner electrophoresis microchips

In this report, we describe the microfabrication and integration of planar electrodes for contactless conductivity detection on polyester-toner (PT) electrophoresis microchips using toner masks. Planar electrodes were fabricated by three simple steps: (i) drawing and laser-printing the electrode geometry on polyester films, (ii) sputtering deposition onto substrates, and (iii) removal of toner layer by a lift-off process. The polyester film with anchored electrodes was integrated to PT electrophoresis microchannels by lamination at 120 degrees C in less than 1 min. The electrodes were designed in an antiparallel configuration with 750 microm width and 750 microm gap between them. The best results were recorded with a frequency of 400 kHz and 10 Vpp using a sinusoidal wave. The analytical performance of the proposed microchip was evaluated by electrophoretic separation of potassium, sodium and lithium in 150 microm wide x 6 microm deep microchannels. Under an electric field of 250 V/cm the analytes were successfully separated in less than 90 s with efficiencies ranging from 7000 to 13,000 plates. The detection limits (S/N = 3) found for K+, Na+, and Li+ were 3.1, 4.3, and 7.2 micromol/L, respectively. Besides the low-cost and instrumental simplicity, the integrated PT chip eliminates the problem of manual alignment and gluing of the electrodes, permitting more robustness and better reproducibility, therefore, more suitable for mass production of electrophoresis microchips.     

Graphene Oxide/ZnO Nano Composite for Sensitive and Selective Electrochemical Sensing of Levodopa and Tyrosine Using Modified Graphite Screen Printed Electrode

Determination of levodopa and tyrosine as two important species for treatment of Parkinson's disease is described. A novel electrochemical sensor involving graphene oxide/ZnO nanorods (GR/ZnO) nano composite and the graphite screen‐printed electrodes (GSPE) was developed for the simultaneous detection of levodopa and tyrosine. The screen‐printed electrodes with several advantages, including low cost, versatility and miniaturization were employed. On the other hand, the graphene oxide/ZnO nanorods nano composite was casted on the surface of GSPE to obtain GR/ZnO/SPE. The proposed nano sensor has excellent performance such as high sensitivity, good selectivity and analytical application in real samples. The combination of graphene oxide/ZnO nanorods nano composite with the screen‐printed electrode is favorable for amplifying electrochemical signals. Under optimized conditions square wave voltammetry (SWV) exhibited linear dynamic ranges from 1.0×10^?6 to 1.0×10^?3 M and 1.0×10^?6 to 8.0×10^?4 M with detection limits of 4.5×10^?7 M and 3.4×10^?7 M for levodopa and tyrosine respectively.     

Solid‐Contact Potentiometric Sensor Based on Polyaniline and Unsubstituted Pillar[5]Arene

A novel potentiometric sensor based on screen‐printed carbon electrode covered with electropolymerized polyaniline (PANI) and unsubstituted pillar[5]arene as ionophore has been developed and tested in potentiometric measurements of pH and metal ions. The introduction of pillar[5]arene improved the reversibility of the pH response in the range from 2.0 to 9.0 with the slope of 45 mV/pH. Among metal cations, the response to Fe³⁺ and Ag⁺ ions was referred to PANI redox conversion whereas the signal toward Cu²⁺ in the range from 1.0×10^?6 to 1.0×10^?2 M (limit of detection (LOD) 3.0×10^?7 M) to specific interaction with the macrocycle.     

Second‐order nonlinear optical responses switching of N∧N∧N ruthenium carboxylate complexes with proton‐electron transfer

In this article, the nonlinear optical (NLO) switching action of Ru(III/II) carboxylate complexes was investigated by density functional theory (DFT). Among the studied complexed, Ru(III)PhCOO^? has the largest β value of 4972 × 10^?30 esu. Through the proton transfer (PT) process, the ? COOH group of Ru(III)PhCOOH and Ru(III)COOH complexes can form the ? COO^? group. Then, ? COO^? group acts as a strong donor and Ru(III) acts as an acceptor, which may be the most favorably used in the development of metal complexes NLO material. The redox NLO switching and PT NLO switching of Ru(III)PhCOO^?, Ru(III)PhCOOH, Ru(II)PhCOO^?, and Ru(II)PhCOOH complexes have been studied. The β value of Ru(III)PhCOO^? complex is ～36 and ～48 times larger than those of reduced Ru(II)PhCOO^? and Ru(II)PhCOOH, respectively. Note that the β value of deprotonated Ru(III)PhCOO^? is ～215 times larger than that of Ru(III)PhCOOH. The molecular electrostatic potential analysis also confirms that Ru(III)PhCOOH may have poor performance in the second‐order NLO response. In addition, the TDDFT calculations show that the ligand to metal charge transfer transition lead to the largest β value of the Ru(III)PhCOO^? complex. This investigation provides important insight into the remarkably large NLO properties and NLO switching of Ru(III/II) carboxylate complexes. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem 000: 000–000, 2011     

Manufacture and demonstration of organic photovoltaic‐powered electrochromic displays using roll coating methods and printable electrolytes

Electrochromic devices (ECDs) were prepared on flexible substrates using spray coating and slot‐die coating methods. The electrochromic materials were the conjugated electroactive polymers, poly((2,2‐bis(2‐ethylhexyloxymethyl)‐propylene‐1,3‐dioxy)‐3,4‐thiophene‐2,5‐diyl) as a vibrantly colored active material (ECP‐Magenta) and poly(N‐octadecyl‐(propylene‐1,3‐dioxy)‐3,4‐pyrrole‐2,5‐diyl) as a minimally colored, charge balancing material (MCCP). Two electrolyte systems were compared to allow development of fully printable and laminated devices on flexible substrates. Devices of various sizes, up to 7 × 8 cm², are demonstrated with pixelated devices containing pixel sizes of 4 × 4 mm² or 13 × 13 mm². The transmission contrast exhibited by the devices, when switched between the fully bleached and fully colored state, was 58% at a visible wavelength of 550 nm, and the devices exhibited switching times of <10 s. Additionally, we demonstrate the utilization of printed organic photovoltaic devices (with or without the use of a lithium‐polymer battery) to power the devices between the colored and bleached state, illustrating a self‐powered ECD. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Flow‐Injection Spectrophotometric Determination of N‐acetylcysteine in Pharmaceutical Formulations with On‐Line Solid‐Phase Reactor Containing Zn(II) Phosphate Immobilized in a Polyester Resin

Abstract

A flow‐injection spectrophotometric procedure was developed for determining N‐acetylcysteine in pharmaceutical formulations. The sample was dissolved in deionized water and 400 µl of the solution was injected into a carrier stream of 1.0×10^?2 mol l^?1 sodium borate solution. The sample flowed through a column (70 mm length×2.0 mm i.d.) packed with Zn₃(PO₄)₂ immobilized in a polymeric matrix of polyester resin and Zn(II) ions were released from the solid‐phase reactor because of the formation of the Zn(II) (N‐acetylcysteine)₂ complex. The mixture merged with a stream of borate buffer solution (pH 9.0) containing 5.0×10^?4 mol l^?1 Alizarin red S and the Zn(II)Alizarin red complex formed was measured spectrophotometrically at 540 nm. The analytical curve was linear in the N‐acetylcysteine concentration range from 3.0×10^?5 to 1.5×10^?4 mol l^?1 (4.9 to 24.5 µg ml^?1) with a detections limit of 8.0×10^?6 mol l^?1 (1.3 µg ml^?1). The relative standard deviations (RSDs) were smaller than 0.5% (n=10) for solutions containing 5.0×10^?5 mol l^?1 (8.0 µg ml^?1) and 8.0×10^?5 mol l^?1 (13.0 µg ml^?1) of N‐acetylcysteine, and the analytical frequency was 60 determinations per hour. A paired t‐test showed that all results obtained for N‐acetylcysteine in commercial formulations using the proposed flow‐injection procedure and a comparative procedure agreed at the 95% confidence level.     

Rapid separation of post‐blast explosive residues on glass electrophoresis microchips

This study describes the development of an analytical methodology based on the use of microchip electrophoresis (ME) devices integrated with capacitively coupled contactless conductivity detection (C⁴D) for the separation and detection of inorganic anions in post‐blast explosive residues. The best separation condition was achieved using a running buffer composed of 35 mmol/L lactic acid, 10 mmol/L histidine and 0.070 mmol/L cetyl(trimethyl ammonium) bromide. For C⁴D measurements, the highest sensitivity was obtained applying a 700 kHz sinusoidal wave with excitation voltage of 20 V_pp. The separation of Cl^?, NO₃^?, NO₂^?, SO₄^2?, ClO₄^? and ClO₃^? was performed within ca. 150 s with baseline resolution and efficiencies between 4.4 × 10⁴ and 1.7 × 10⁵ plates/m. The found limits of detection ranged between 2.5 and 9.5 μmol/L. Last, real samples of post‐blast explosive residues were analyzed on the ME‐C⁴D devices obtaining successfully the determination of Cl^?, NO₃^? and SO₄^2?. The achieved concentration values varied between 12.8–72.5 mg/L for Cl^?, 1.7–293.1 mg/L for NO₃^? and 1.3–201.3 mg/L for SO₄^2?. The data obtained using ME‐C⁴D devices were in good agreement with the concentrations found by ion chromatography. The approach reported herein has provided short analysis time, instrumental simplicity, good analytical performance and low cost. Furthermore, the ME‐C⁴D devices emerge as a powerful and portable analytical platform for on‐site analysis demonstrating to be a promising tool for the crime scene investigation.     

Preparation and evaluation of amphiphilic silica‐based monolithic column having surface‐bound octanoyl‐aminopropyl moieties for capillary electrochromatography

A novel amphiphilic silica‐based monolithic column having surface‐bound octanoyl‐aminopropyl moieties was successfully prepared by a one‐step in situ derivatization process. As expected, the amphiphilic monolithic column exhibited RP chromatographic behavior toward non‐polar solutes (e.g., alkyl benzenes) with high column performance. As the pH of the buffer inside the column increases, the EOF changed from −2.65×10⁻⁸m² V⁻¹s⁻¹ at pH 3.0 to 1.20×10⁻⁸ m² V⁻¹s⁻¹ at pH 8.0 with the reversion of EOF at about pH 6.4. Using acidic mobile phase, five aromatic acids can be efficiently separated in less than 6 min under co‐EOF conditions. For basic compounds, symmetrical peaks were obtained due to the existence of hydrophilic acyl amide group, which can effectively minimize the adsorption of the positively charged basic analyte to the silica‐based surface of the capillary column.     

Low‐voltage efficient electroosmotic pumps with ultrathin silica nanoporous membrane

In this work, an efficient electroosmotic pump (EOP) based on the ultrathin silica nanoporous membrane (u‐SNM), which can drive the motion of fluid under the operating voltage as low as 0.2 V, has been fabricated. Thanks to the ultrathin thickness of u‐SNM (～75 nm), the effective electric field strength across u‐SNM could be as high as 8.27 × 10⁵ V m^?1 in 0.4 M KCl when 1.0 V of voltage was applied. The maximum normalized electroosmotic flow (EOF) rate was as high as 172.90 mL/min/cm²/V, which was larger than most of other nanoporous membrane based EOPs. In addition to the ultrathin thickness, the high porosity of this membrane (with a pore density of 4 × 10¹² cm^?2, corresponding to a porosity of 16.7%) also contribute to such a high EOF rate. Moreover, the EOF rate was found to be proportional to both the applied voltage and the electrolyte concentration. Because of small electrokinetic radius of u‐SNM arising from its ultrasmall pore size (ca. 2.3 nm in diameter), the EOF rate increased with increasing the electrolyte concentration and reached the maximum at a concentration of 0.4 M. This dependence was rationalized by the variations of both zeta potential and electrokinetic radius with the electrolyte concentration.     

Cyclodextrin Modified Carbon Paste Based Electrodes as Sensors for the Determination of Carcinogenic Polycyclic Aromatic Amines

Voltammetric properties and possibility of the determination of carcinogenic aminoderivatives of polycyclic aromatic hydrocarbons, namely 1‐ and 2‐aminonaphthalene and 2‐aminobiphenyl, have been investigated. Carbon paste electrodes (CPE) modified with monomeric α‐, β‐ or γ‐cyclodextrin and carbon‐based screen‐printed electrodes (SPE) surface‐modified with a thin film of β‐cyclodextrin (β‐CDP) or carboxymethylated β‐cyclodextrin (β‐CDPA) condensation polymer were used for that purpose as simple electrochemical biosensors. Analytical procedure for the DPV determination of tested amines using these biosensors was proposed. Linear calibration plots within the concentration range of 2×10^?8 – 2×10^?7 mol dm^?3 and 2×10^?7–1×10^?6 mol dm^?3 with limits of quantification of the order of 10^?9 mol dm^?3 were obtained for the modified CPE and modified SPE.     

Spectrophotometric Determination of Furosemide Based on Its Complexation with Fe(III) in Ethanolic Medium Using a Flow Injection Procedure

Abstract

A fast flow injection procedure with spectrophotometric detection based on the furosemide complexation with Fe(III) ions in ethanolic media is described. As carrier the flow single line system configuration used an ethanolic 10^?2 mol L^?1 Fe(III) solution flowing at 1.0 mL min^?1, a 50 cm sample loop (250 µL total sample injection), and a 50 cm long reactor coil, at room temperature. The detection at 513 nm presented a linear dynamic range from 1.00×10^?4 to 1.00×10^?2 mol L^?1, obeying the linear equation Abs=8.9×10^?3+22.3×[furosemide] (r=0.998, n=7). The limit of detection (3σ/slope) was 3.00×10^?5 mol L^?1. The proposed method was applied to four commercial samples from different suppliers, as tablets and ampoules, and a synthetic urine sample spiked with the analyte without an effect from the other substances present in the formulation. The proposed procedure presented an analytical frequency of 95 measurements per hour. The results agreed with those from both the label and those determined by a spectrophotometric comparative procedure. Recoveries close to 100% were found in the commercial formulations and synthetic urine matrixes.     

Synthesis of New Reagent 2,6‐Diacetylpyridine Bis‐4‐Phenyl‐3‐Thiosemicarbazone (2,6‐DAPBPTSC): Selective,Sensitive and Extractive Spectrophotometric Determination of Co(II) in Vegetable,Soil, Pharmaceutical and Alloy Samples

New synthesized reagent 2,6‐diacetylpyridine bis‐4‐phenyl‐3‐thiosemicarbazone (2,6‐DAPBPTSC) is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of cobalt(II). Cobalt(II) forms a reddish brown colored complex with 2,6‐DAPBPTSC, which is extracted into isoamylalcohol, under optimum conditions. The maximum absorption of the isoamylalcohol extract is measured at 400 nm. Beer's law is applied in the range 0.6‐6.0 ppm of cobalt(II). The molar absorptivity and Sandell's sensitivity of the complex is calculated as 2.2 × 10⁴ L mol^?1 cm^?1 and 2.68 × 10^?3 μg cm^?2, respectively. An adequate linearity with a correlation coefficient value of 0.969 is obtained for the Co(II)‐2,6‐DAPBPTSC complex. The instability constant of the complex, calculated from Asmus' method is 3.75 × 10^?4 The precision and accuracy of the method is checked with calculation of relative standard deviation (n = 5), 0.388 and the detection limit a value is 0.0028 μg mL^?1. The method is successfully employed for the determination of cobalt(II) in real samples, such as vegetables, soil, water samples, standard alloy samples, and the performance of the present method was evaluated in terms of Student ‘t’ test and Variance ‘f’ test, which indicates the significance of the present method is an inter comparison of the experimental values, using atomic absorption spectrometer (AAS).