Methylthymol Blue Research Articles

Development of a Paper-Based Analytical Method for the Colorimetric Determination of Calcium in Saliva Samples

A novel, rapid, and facile method for the colorimetric determination of calcium using micro-analytical paper-based devices (μ-PADs) was developed. The proposed analytical method utilizes the color differences developing, after the addition of calcium, on the surface of the devices because of the complexation reaction of calcium with Methylthymol Blue (MTB) at room temperature, in alkaline pH. The devices were manufactured with chromatographic paper, using wax barriers, and the analytical protocol was easily implemented without the need of any experimental apparatus except for a simple imaging device. The user must regulate the pH, add the solutions on the paper, and measure the color intensity of the formed Ca(II)-MTB complex with a flatbed scanner. The experimental conditions for optimum color development, the possible interfering substances, and the reliability of the paper devices in different preserving conditions were optimized, with satisfactory results. The method exhibited acceptable detection limits (2.9 mg L-1) with sufficiently good precision, which varied from 4.2% (intra-day) to 6.4% (inter-day). Saliva samples from healthy volunteers were successfully analyzed, and the calcium levels were calculated in the range of 30.71 to 84.15 mg L-1.

Development of a Paper-Based Analytical Method for the Selective Colorimetric Determination of Bismuth in Water Samples

A novel, direct and simple colorimetric method employing μicroanalytical paper-based devices (μ-PADs) for the selective determination of bismuth is described. The suggested method exploits the colorimetric variation of bismuth after its rapid reaction with methyl thymol blue (MTB) in an acidic medium (pH ranging between 0.7 and 3.0), modified with nitric acid, on the surface of a paper device at room temperature. The devices are low cost, composed of chromatographic paper and wax barriers and the analytical protocol is easily applicable with minimal technical expertise and without the need for experimental apparatus. The user must add a test sample and read the color intensity of the colored Bi(III)–MTB complex formed at the sensing area using a simple imaging device such as a flatbed scanner. Various chemical variables, such as HNO3 and MTB concentration, reaction time, ionic strength, detection zone size and photo-capture detector are optimized. A study of interfering ions such as K+, Na+, Ca2+, Mg2+, Cl−, SO42− and HCO3− was also conducted. The stability of the paper devices is also studied in different maintenance conditions with particularly satisfactory results, rendering the method suitable for field analysis. The detection limits are as low as 3.0 mg L−1 with very satisfactory precision, ranging from 4.0% (intra-day) to 5.5% (inter-day). Natural water samples are successfully analyzed, and bismuth percentage recoveries were calculated in the range of 82.8 to 115.4%.

Improved production of titanate nanotubes by hydrothermal method for adsorption of organic dyes

BackgroundIncreasing the yield of nanomaterials using the same reactor size and fixing most of the reactants and conditions will greatly improve the production process by saving time, energy and efforts. Titanate nanotubes are mainly prepared by hydrothermal process, in which TiO2 powder reacts with NaOH at certain conditions to form the desired nanotubes. It was reported that it is a must to use high concentrations of NaOH (10 N) to enable the tubular form formation, and the amount of NaOH from the stoichiometry point of view is much higher than that of TiO2; this means excess amounts of NaOH are not used and washed off. This work was designed to improve the production yield by making use of this excess amount of NaOH.ResultsMore than 60 g of sodium titanate nanotubes was prepared using simple hydrothermal method. The prepared nanotubes were characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy and BET surface area analysis. The adsorption capacity of these nanotubes was tested against three commonly used dyes: methyl orange, crystal violet and thymol blue. The samples showed great affinity toward crystal violet and lower activity toward methyl orange and thymol blue, where they achieved more than 90% removal efficiency under different experimental conditions.ConclusionsSodium titanate nanotubes were prepared in large amounts using modified hydrothermal method. The obtained nanotubes efficiently removed crystal violet from water. This improved synthesis of titanate nanotubes will reduce the total cost of nanomaterials production, and subsequently the treatment process, since titanate nanotubes are used in adsorption and photocatalysis processes.

Study of interaction of metal ions with methylthymol blue by chemometrics and quantum chemical calculations

In this study, we determine the acidity constants of methylthymol blue (MTB) and association constants of its complexes with the ZnII, CuII, and FeII metal ions (MIs), through theoretical and experimental means. The complexes were characterized using UV–Visible absorption spectroscopy combined with soft/hard chemometrics methods and quantum chemical calculations. Quantum chemical calculations revealed that electronic transitions in the UV–Visible spectra of MTB have mixed n → π* and π → π* characters. The results of molar ratio and multivariate curve resolution alternating least squares (MCR-ALS) revealed the formation of successive 1:2 and 1:1 complexes (MI:MTB) for the ZnII and CuII systems. However, the formation of successive 1:1 and 2:1 complexes are suggested for FeII by the molar ratio and MCR-ALS. The majority of transitions observed in the UV–Visible spectra of the Zn(MTB) and Cu(MTB) complexes have ligand-to-ligand charge transfer (LLCT) characters. However, the transitions in the UV–Visible spectrum of the Fe(MTB) complex have LLCT and metal-to-ligand charge transfer (MLCT) characters. For the Fe2(MTB) complex, the lowest energy transition of has an LLCT character. However, its higher energy transitions are a mixture of LLCT, MLCT, and metal-to-metal charge transfer (MMCT) characters. The correlation between experimental and computed wavelengths revealed that the 1:1 complexes of ZnII and CuII prefer square pyramidal geometries. However, the FeII complexes always show octahedral geometry.

Methyl thymol blue solution and film dosimeter for high dose measurements

A novel radio-chromic solutions and polyvinyl alcohol (PVA) films with different concentrations of methyl thymol blue (MTB) dye have been investigated and studied for high dose applications. The MTB dosimeters were exposed to irradiation using gamma ray 60Co source from 2.5 to 50 kGy for film, and from 0.10 to 2.5 kGy for solutions. The radio-chromic dosimeters were investigated using ultraviolet visible (UV–Vis) spectrophotometry. The effect of MTB dye concentration, relative humidity, and stability of the dosimeters were investigated. The results show that the dose response sensitivity of the dosimeters improved significantly with increasing the absorbed dose and MTB dye concentrations. The un-irradiated and irradiated dosimeters show a perfect stability for one week. Hence, these films can be used as dosimeters in industrial radiation processing. The study shows that the useful dose range is in the range of 2.5–20 kGy and 0.1–1.2 kGy, for film and solution dosimeters, respectively.

Nuclear magnetic resonance analysis of a chemically cross-linked ferrous–methylthymol blue–polyvinyl alcohol radiochromic gel dosimeter

A new formulation of hydrogel dosimeter consisting of ferrous–methylthymol blue (MTB)–polyvinyl alcohol (PVA) cross-linked chemically with glutaraldehyde (GTA) was studied and evaluated by nuclear magnetic resonance analysis by means of the R2 spin-spin relaxation rate. Previous optical studies of this transparent solid chemically cross-linked gel showed important dosimetric features in terms of sensitivity, auto-oxidation rate, and diffusion. This study shows that the MTB-PVA-GTA dosimeter has a reproducible linear dose response up to 40 Gy. For the optimum formulation of 0.1 mM MTB, 2.5% PVA, and 26.6 mM GTA, the measured R2 sensitivity was higher than that of traditional natural matrix–containing gels (MTB-gelatin) and all other reported PVA gel–based radiochromic dosimeters with MTB, xylenol orange (XO), or GTA (MTB-PVA, XO-PVA, XO-PVA-GTA). Additionally, the auto-oxidation rate was approximately ten times lower than that of the Fricke-MTB-gelatin system, which is consistent with the spectrophotometry results. The results of the independent experimental spectrophotometry and nuclear magnetic resonance analyses indicate that the transparent cross-linked dosimeter has good and consistent dosimetric features.

Acid-treated clay catalysts for organic dye ozonation - Thorough mineralization through optimum catalyst basicity and hydrophilic character.

Catalytic ozonation of Methylene Blue, Methyl Green, Methyl Orange and Methyl-thymol Blue was investigated in the presence of ion-exchanged montmorillonite (NaMt and Fe(II)Mt), crude bentonite and acid-activated counterparts. An original approach never tackled so far consisted in correlating the basicity and hydrophilic character to the dye-catalyst interactions occurring on the catalyst surface. This was achieved through CO2 and water thermal programmed desorption. Kinetics study revealed that ozonation starts in the bulk solution, and dye adsorption turns out to be an essential requirement for high catalytic effectiveness. On NaMt, dye molecules appear to adsorb mainly via hydrophobic interaction. On Fe(II)Mt, the contributions of hydrophobic interaction, cation-exchange and Fe2+ mobility to the catalytic activity prevail. Acid activated clay catalysts exhibited lowest hydrophilic character favoring adsorption through organophilic interaction and affording thorough and fast dye mineralization. This was explained in terms of increased number of silanols and -Si-O-Si- groups. For all catalysts, short ozonation of all dye molecules resulted in similar end-chain products, which were totally eliminated after prolonged reaction times. This result is of great importance because it provides valuable theoretical findings that allow envisaging total mineralization of organic molecules by recyclable metal-free clay catalysts.

On the mechanism of indium(III) complex formation with metallochromic indicators

The equilibria and kinetics of the interaction of In(III) with Alizarin Red S (ALZS) and Methyl Thymol Blue (MTB) dyes in aqueous solution were investigated. Spectrophotometric titrations at different pHs (1.8–2.7 range) revealed that, concerning the In-ALZS system, under conditions of metal excess the prevailing complex is ML, while stopped flow experiments have shown that, in the investigated pH range the kinetics are monophasic although the ML complex is formed through different paths involving both In(H2O)63+ and In(H2O)5(OH)2+ as active species reacting with the monoprotonated ligand (HL). The In-MTB system was studied with the same methodology in the pH range 1.0–2.0. The complex (MH3L) prevails although the above metal species react with differently protonated forms of the ligand. The In-MTB system displays a biphasic kinetic behavior involving a network of reaction steps, where fast pre-equilibria related to metal coordination at the carboxylates/nitrogen site, precedes slow coordination at the phenol/phenol or phenol/quinone sites. The key role in the reaction mechanism is played by the ligand features rather than by the solvent/ligand substitution process.

Investigation of chelating agents/ligands for Fricke gel dosimeters

The Fricke solution is an absolute dosimeter which can be combined with some metal-binding organic ligands and thus show measured radiation doses through visible light absorption effects. Adding the solution to a gel matrix also allows mapping doses three-dimensionally, and is known as Fricke-gel dosimetry. The latter has some drawbacks that hinder its practical usage for 3D mapping, namely signal diffusion effects and spontaneous color changes due to auto-oxidation. Ligands play a major role in this respect and xylenol orange has been used extensively. Several alternative ligands and their interactions with Fricke solutions and gels were investigated in this study. Among these ligands, calcichrome (CH), eriochrome blue (EB), methylthymol blue (MTB), and naphthol green (NG) showed the required differentiation between optical absorbance of ferrous vs ferric ions. While our study confirmed the overall advantages of using xylenol orange, it also suggests that methylthymol blue offers potential worthy of further investigation.

Microwave-mediated synthesis, photocatalytic degradation and antibacterial activity of [formula omitted]-Bi2O3 microflowers/novel [formula omitted]-Bi2O3 microspindles

The present article portray the microwave (MW) synthesis of alpha bismuth oxide microflowers (α-Bi2O3 MFs) and novel gamma bismuth oxide microspindles (γ-Bi2O3 MSs) using bismuth nitrate pentahydrate [Bi(NO3)3.5H2O], and polyvinylpyrrolidone (PVP) as a surfactant. The structural, BET surface area, morphological, photocatalytic activity under ultraviolet (UV) light and antibacterial performance was investigated with varying MW irradiation time. XRD study confirmed the formation of monoclinic (α-phase) and body-centered cubic (γ-phase) of Bi2O3 with variation of MW irradiation time for 10 min and 15 min respectively. SEM images revealed the formation of microflowers for α-Bi2O3 and microspindles for γ-Bi2O3. Further HR-TEM illustrated the appearance of nanoflakes (19–35 nm) and the rose-flowers, and back-bending man (15–30 nm) like structures for α-Bi2O3 MFs and γ-Bi2O3 MSs correspondingly. Interestingly, the comparative photocatalytic activity of α-Bi2O3 MFs and γ-Bi2O3 MSs were evaluated under UV-light irradiation for the degradation of five different dyes viz. malachite green (MG), eriochrome black-T (EBT), methyl thymol blue (MTB), bromophenol blue (BPB), and congo-red (CR). The α-Bi2O3 MFs show enhanced photocatalytic activity than γ-Bi2O3 MSs under UV light without decreasing efficiency up to four consecutive cycles and fallows the pseudo-first order reaction kinetics and degradation order: MTB>MG>EBT>CR>BPB. Furthermore, antibacterial assay of α-Bi2O3 MFs and γ-Bi2O3 MSs was carried out against gram-positive (Staphylococcus aureus (S a) and Pseudomonas aeruginosa (P a)) and gram-negative (Escherichia coli (E c), and Klebsiella Pneumonia (K p)) human pathogenic bacteria using agar well diffusion method. The α-Bi2O3 MFs show comparatively better antibacterial activity against P a than γ-Bi2O3 MSs. The current study provides a simple approach to design the α-Bi2O3 MFs and novel γ-Bi2O3 MSs as a photocatalyst for the environmental remediation of organic pollutants (OPs).

Quantitative Spectrophotometric Determinations of Fe3+ in Iron Polymaltose Solution

The aim of this investigation was to develop a spectrophotometric method in the visible range for quantitative determination of Fe3+ in a pharmaceutical formulation based on complexation with methylthymol blue. The reaction occurred at a temperature of 30° and the absorbance remains constant after 25-30 min; the blue-colored resulting complex had a maximum absorption at 628 nm. The combination ratio was established through the Job’s method of continuous variations. In acetate buffer (pH=5), Fe3+ forms a complex of 1:1 with methylthymol blue. Lambert-Beer law was obeyed to the concentration area of (2-6) µg/ml; the calibration curve is described by the regression line A= 0.1025° (µg/ml) -0.0013 with a correlation coefficient of R2= 0.9997. For the validation of the method the following parameters were studied, linearity, accuracy, limit of detection, limit of quantification and retrieval. Confidence interval of the average retrieval ranged from 98.79 to 101.13 %. The non-interference of excipients in the solution makes the method suitable for routine dosage of iron in polymaltose complexes. This visible spectrophotometric method was applied to determine Fe3+ concentration in polymaltose iron complex. The validation parameters confirmed that this method could serve to determine Fe3+.

53. Characterisation of TruView™: A new 3-D reusable radiochromic MethylThymol Blue based gel dosimeter for ionising radiations

Introduction Cutting-edge radiotherapy techniques deliver highly conformal treatments with steep dose gradients around the target volume. Thus, the verification of the complex resultant dose distributions presents a real dosimetric challenge requiring accurate and spatially precise dosimeters. Gel dosimetry is a promising technique as it can inform about the whole 3-D dose distribution in one irradiation and without conventional dosimeters issues [1] . This study focuses on the characterisation of the new TruView™ gel dosimeter (Modus Medical Devices Inc.). This dosimeter is based on Fricke-MTB composition [2] but presents a new MethylThymol Blue (MTB) reactive dye and a reusable structure. The dosimetric properties of this gel dosimeter and the influence of different parameters on its response are presented. Methods The key dosimetric aspects (dose response, dependence with energy and dose rate) and the TruView™ dosimeter variability with different parameters (gel temperature, light exposure, time between irradiation and reading, etc.) were studied thanks to spectrophotometric measurements. Finally, by mean of optical CT scanning (Vista™, Modus Medical Devices Inc.), its performances to measure relative depth dose (PDD) and cross profiles have been analysed. Results TruView™ presents linear response with dose up to 20 Gy independent of both photon beam energy and dose rate on the studied ranges. The study of the numerous parameters influencing its dose response enabled to determine the optimal conditions for using this gel. In those conditions, the comparison of TruView™ relative depth dose (PDD) and of cross profiles with ion chamber measurements shows a good dosimetric and spatial precision with 90% of the points passing the 3 mm 3% gamma test for the PDD and 87% for the cross profiles. Seven days after irradiation, ion diffusion inside the gel leads to return to homogeneity allowing a new irradiation to be performed. The TruView™ response presents an excellent reproducibility as 100% of the points pass the gamma test for the comparison between the PDD of the two uses and 94% for the cross profiles. Conclusions This study provides important knowledge regarding the 3-D gel dosimeter TruView™. This dosimeter presents interesting dosimetric properties but remains delicate to use due to the great response sensitivity to numerous parameters. A further study is currently ongoing to benchmark this promising candidate for clinical dose verification.

Evaluation of ferrous Methylthymol blue gelatin gel dosimeters using nuclear magnetic resonance and optical techniques

Signal development of irradiated Methylthymol blue (MTB) Fricke gelatin gel dosimeter was studied using nuclear magnetic resonance (NMR) in terms of the spin-spin relaxation rate (R2) of hydrogen protons within the water molecule. The optical properties of MTB gel were also studied using a spectrophotometric technique. The gel dosimeter presents a linear response for doses up to 20 Gy with ultraviolet visible (UV-Vis) spectrophotometry and 40 Gy with NMR. For a 0.1 mM MTB concentration and dose of up to 10 Gy, the sensitivity of the gel response analyzed by a spectrophotometer is 0.077 a.u. Gy−1 at 620 nm with a linear coefficient of (r2 = 0.998), while the R2 sensitivity is 0.02 s−1 Gy−1 with a linear coefficient of (r2 = 0.998). The sensitivity of the Fricke-MTB dosimeter was higher when compared with the Fricke-XO dosimeter. The dose rate and photon energy beams were dependent of the absorbance and R2 dose sensitivity, as observed over the range studied. The Fricke-MTB gelatin dosimeters can be scanned at higher wave lengths than the conventional Fricke-XO gelatin formulations.

Copper-doped modified ZnO nanorods to tailor its light assisted charge transfer reactions exploited for photo-electrochemical and photo-catalytic application in environmental remediation

The amount of dopant concentration, alongwith the choice of dopant, is one of the most conducive factor for the favourable outcome for light driven activities of a material. The present paper reports on the synthesis of zinc oxide nanorods doped with different concentrations of copper (Cu–ZnO) by simple, low-cost mechanical assisted thermal decomposition process. The as synthesized samples were tested for visible light driven photo-electrochemical (PEC) and photocatalytic activities on various hazardous dyes using methylene blue (MB), methyl orange and mixed green dye (methyl thymol blue + methylene blue). The study helped us to reveal that highest degradation efficiency was achieved for Cu concentration of 5% in ZnO on MB (91.1% degradation in 40 min). Compared to pure ZnO, the photoactivity of 5% Cu–ZnO composites shows higher photodegradation of dyes. Moreover, the photocatalytic results were found consistent with PEC studies which showed maximum current generation of +9.4 mA for 5% Cu–ZnO (carried out under dark and illumination condition). The mechanism for this enhanced photoactivity has been proposed based on the relationship established between oxygen vacancies and defects generation in the material due to different doping concentrations that directly influence its photocatalytic efficiency.

Application of a new version of GA-RBF neural network for simultaneous spectrophotometric determination of Zn(II), Fe(II), Co(II) and Cu(II) in real samples: An exploratory study of their complexation abilities toward MTB

The current study for the first time is devoted to the application of whole space genetic algorithm-radial basis function network (wsGA-RBFN) method to determine the content micro minerals of Zn2+, Fe2+, Co2+ and Cu2+ based on their complexes formation with methylthymol blue (MTB) spectrophotometrically in various pharmaceutical products and vegetable samples. Advantage of wsGA-RBFN compared to GA-RBFN is that centers can be located in any point of the samples spaces. Initially, the parameters controlling behavior of the system were investigated and optimum conditions were selected. Then, an exploratory analysis of complex systems was carried out by chemometrics approaches such as SVD, EFA, MCR-ALS and RAFA. The optimal parameters and conditions for constructing the proposed model of wsGA-RBFN were obtained from processing the data set of synthetic samples. Finally, wsGA-RBFN was successfully applied to the simultaneous determination of Zn2+, Fe2+, Co2+ and Cu2+ in tomato, white cabbage, red cabbage and lettuce and pharmaceutical products included iron, zinc, multi complete and B12 ampoule.

Multivariate optimisation of a rapid and simple automated method for bismuth determination in well water samples exploiting long path length spectrophotometry

ABSTRACTAn automated spectrophotometric system is proposed for the determination of bismuth in well water samples, using multi-syringe flow injection analysis (MSFIA) and exploiting a liquid waveguide capillary cell (LWCC). This method is based on the colorimetric reaction of bismuth and methylthymol blue (MTB) in the presence of polyvinylpyrrolidone (PVP) in acid medium (0.1 mol L−1 HNO3). The Bi(III)–MTB complex was measured at 600 nm. The method was optimised by multivariate techniques. Some figures of merit of the proposed system are worth being highlighted, such as its wide linear working range (between 4.9 and 600 μg L−1), its low detection limit (1.5 μg L−1 of bismuth) and its high intra-day precision and inter-day precision (0.7% (n = 12) and 1.4% (n = 5), respectively, both expressed as RSD). Moreover, a high injection frequency of 30 h−1 is achieved, as the proposed analyser is a powerful tool for fast Bi(III) determination. The method developed was successfully validated by analysing reference samples (pharmaceutical samples) by comparing the results with those obtained by ICP-OES and it was satisfactorily applied to well water samples. Besides, the present system is miniaturised allowing in situ measurements in control processes and field analysis.

Methylthymol blue in Fricke gels

The initial trial of methylthymol blue (MTB) as a chelator for ferric iron in Fricke gel dosimeters, used for three-dimensional (3D) dosimetry in cancer radiotherapy, is reported. MTB is a structural analogue of the conventionally used xylenol orange (XO); however, the absorbance spectrum of the ferric-MTB complex is shifted to higher wavelengths, which should allow for lower amount of light scattering during gel scanning. In this study, two gelatin substrates, two sources of XO and one source of MTB have been compared. The MTB- containing gels exhibited similar dose response and diffusion coefficient to the XO-containing gels at their wavelengths of maximum absorption (620 and 585 nm, respectively). In addition, the MTB gels gave an excellent dose response at 633 nm, which is an important wavelength that is already used with other 3D dosimeters.

Interference of Bilirubin in the Determination of Magnesium with Methyl Thymol Blue.

Introduction:Jaundice is a disease named for the yellow color of the skin. This color is the result of elevated levels of bilirubin in the blood serum. In Roma from Krusevac region in the last few years have seen the emergence of jaundice.Material and methods:In 80 of them (40 suffering and 40 from control group) were performed tests of numerous parameters in the laboratories of the Health Center in Krusevac. Magnesium was determined by spectrophotometry with methyl thymol blue, titanium yellow and blue xylidene. Bilirubin was determined by Jandrešek Grofov’s method.Results:The results were within the expectations, in addition to magnesium which was determined with methyl thymol blue. In all patients suffering from jaundice concentration of magnesium (0.67 ±0.14 mmol/l) statistically was significantly lower than tested of the control group (0.91± 0.059 mmol/). There is no theoretical data to reduce the concentration of magnesium in serum as a result of jaundice. That’s why we determined magnesium both in the control group and in sufferings with two methods as the titanium yellow, and xylidene blew. With these two methods we obtained results that were examined were within normal limits.Conclusion:This has led us to conclude that the determination of bilirubin interferes with magnesium methyl thymol blue.

Discriminate sensing of pyrophosphate using a new tripodal tetramine-based dinuclear Zn(II) complex under an indicator displacement assay approach.

In this research, the dinuclear Zn(ii) complex of anthracene based tripodal tetramine Zn2L was synthesized, and its sensing abilities towards anions was investigated using the indicator displacement assay (IDA) approach with four complexometric indicators: pyrocatechol violet (PV), bromopyrogallol red (BPG), methylthymol blue (MTB) and xylenol orange (XO). UV-vis spectrophotometry results indicated that the Zn2L-MTB ensemble sensor could discriminate the pyrophosphate anion (PPi) from other phosphate containing anions. (1)H and (31)P NMR spectroscopy as well as DFT calculations confirmed that PPi bound to Zn2L in a 2 : 2 manner. Both NMR spectroscopy and UV-vis spectrophotometry suggested that the two bulky tripodal tetramine units in Zn2L played an important role to provide the ensemble cleft for MTB, giving rise to an ensemble that could be displaced exclusively by PPi. The detection limit of PPi for the reported IDA system was 0.3 μM in 20% (v/v) water-acetonitrile buffered at pH 7.4 with HEPES.

Determination of calcium in wine using reconfigurable PSoC based spectrophotometer

This paper discusses the determination of calcium in wine samples using Programmable Systemon-Chip (PSoC) microcontroller. This embedded system uses a PSoC CY8C27443 integrated circuit (IC) spectrophotometer as core unit, high intensity orange LED as light source and photodiode as light detector having the relative spectral sensitivity above 93% in the range of 550–650 nm. This single-chip design reduces hardware complexity and increases the stability by miniaturizing the device. The instrument obeys Beer’s law up to the concentration of 160 mg/L. Coloring agent Methylthymol Blue (MTB) forms a complex with calcium in presence of alkali (pH ≈ 12); the complex exhibits maximum absorbance at 610 nm. The spectral range, concentration of MTB and pH of the solution at which the reaction is carried out are optimized. The results of the developed method are compared statistically with those obtained by a conventional method by applying Student’s t-test and F-test. The regression analysis reveals excellent correlation (R2 = 0.9998) and regression line equation obtained for that line Y = 0.29 + 0.99X with standard error of 0.62. It can be concluded that the obtained results are in good agreement with the reference method at 95% confidence level.