Net Analyte Signal Standard Addition Research Articles

Simultaneous Spectrophotometric Determination of Rifampicin, Isoniazid and Pyrazinamide in a Single Step.

Three antituberculosis medications are investigated in this work consist of rifampicin, isoniazid and pyrazinamide. The ultra violet (UV) spectra of these compounds are overlapped, thus use of suitable chemometric methods are helpful for simultaneous spectrophotometric determination of them. A generalized version of net analyte signal standard addition method (GNASSAM) was used for determination of three antituberculosis medications as a model system. In generalized net analyte signal standard addition method only one standard solution was prepared for all analytes. This standard solution contains a mixture of all analytes of interest, and the addition of such solution to sample, causes increases in net analyte signal of each analyte which are proportional to the concentrations of analytes in added standards solution. For determination of concentration of each analyte in some synthetic mixtures, the UV spectra of pure analytes and each sample were recorded in the range of 210 nm-550 nm. The standard addition procedure was performed for each sample and the UV spectrum was recorded after each addition and finally the results were analyzed by net analyte signal method. Obtained concentrations show acceptable performance of GNASSAM in these cases.

Simultaneous Spectrophotometric Determination of Sunset Yellow and Quinoline Yellow in a Single Step

AbstractIn this work a new modified standard addition method for simultaneous spectrophotometric determination of Sunset yellow (SY) and Quinoline yellow (QY) is used. The generalized Net Analyte Signal Standard Addition Method (GNASSAM) was introduced for simultaneous standard addition of analytes. By applying this method the concentrations of analytes are determined in a single step. The applicability of new method was used for the simultaneous determination of strongly overlapped spectra of SY and QY in a real sample without using any separation step. GNASSAM was also used to calculate figures of merit. Moreover, good limits of detection (SY=0.13 and QY=0.16 mg L −1) and suitable selectivity and sensitivity were determined. HPLC method was applied for finding subspace in binary mixtures of real samples. The results of investigated method for real sample were compared with HPLC results. The obtained results were in a good agreement with those of HPLC method.

Thermodynamic Solubility Profile of Carbamazepine–Cinnamic Acid Cocrystal at Different pH

Pharmaceutical cocrystal formation is a direct way to dramatically influence physicochemical properties of drug substances, especially their solubility and dissolution rate. Because of their instability in the solution, thermodynamic solubility of cocrystals could not be determined in the common way like other compounds; therefore, the thermodynamic solubility is calculated through concentration of their components in the eutectic point. The objective of this study is to investigate the effect of an ionizable coformer in cocrystal with a nonionizable drug at different pH. Carbamazepine (CBZ), a nonionizable drug with cinnamic acid (CIN), which is an acidic coformer, was selected to prepare CBZ–CIN cocrystal and its thermodynamic solubility was studied in pH range 2–7. Instead of HPLC that is a costly and time-consuming method, a chemometric-based approach, net analyte signal standard addition method, was selected for simultaneous determination of CBZ and CIN in solution. The result showed that, as pH increases, CIN ionization leads to change in CBZ–CIN cocrystal solubility and stability in solution. In addition, the results of this study indicated that there is no significant difference between intrinsic solubility of CBZ and cocrystal despite the higher ideal solubility of cocrystal. This verifies that ideal solubility is not good parameter to predict cocrystal solubility.

Application of RP–HPLC method in dissolution testing and statistical evaluation by NASSAM for simultaneous estimation of tertiary combined dosages forms

A dissolution method with robust high performance liquid chromatographic (HPLC) analysis for immediate release tablet formulation was developed and validated to meet the requirement as per International Conference on Harmonization (ICH) and United States Food and Drug Administration (USFDA) guidelines. The method involved the use of Agilent ZORBAX Eclipse XDB C18 column, and temperature was maintained at 30°C. After optimization, the mobile phase was selected as phosphate buffer (KH2PO4, 30mM) : ACN (60:40, v/v) with pH 3.0, and retention time Rt was found as 3.24, 4.16, and 2.55min for paracetamol (PCM), chlorpheniramine maleate (CPM) and phenylephrine hydrochloride (PH) respectively at 265nm and at a flow rate of 1mL/min. The relative standard deviation (%RSD) for 6 replicate measurements was found to be less than 2%. Furthermore net analyte signal standard addition method (NASSAM) with spectrophotometer was performed for standard and liquid oral suspension. On the basis of selectivity, sensitivity and accuracy analysis, it was confirmed that this novel method could be useful for simultaneous estimation of the given drug combinations. Two-way analysis of variance (ANOVA) was applied for evaluating the statistical difference between the assay results obtained via both NASSAM and RP–HPLC methods and ultimately no significant difference was found between both the methods. All the methods and results were acceptable and confirmed that the method was suitable for intended use.

Simultaneous standard addition method for novel determination of components in a single step: application in analysis of Sunset yellow and Carmoisine by a spectrophotometric technique

Recently a novel method for determination of an analyte in the presence of known interferences called the net analyte signal standard addition method (NASSAM) was introduced. Although NASSAM was used for individual standard addition, a novel generalized net analyte signal standard addition method (GNASSAM) was used for simultaneous standard addition. By applying the proposed method, simultaneous determination of components was done in a single step. Also, this method can be applied for linearly dependent concentrations. Sunset yellow and Carmoisine demonstrate strong spectra overlap with typical application of a spectrophotometry technique. GNASSAM was used for simultaneous determination of Sunset yellow and Carmoisine in synthetic binary mixtures and real samples. The investigated method was also used to calculate figures of merit; moreover, good limits of detection (SY = 0.15 and CA = 0.18 mg L−1) and suitable selectivity and sensitivity were determined. A HPLC method was applied for finding the subspace in binary mixtures of real samples. The obtained results for real samples were compared with the HPLC results. The obtained results were in good agreement with those of the HPLC method.

Bismuth and Bismuth-Chitosan modified electrodes for determination of two synthetic food colorants by net analyte signal standard addition method

Abstract In this paper, an electrochemical application of bismuth film modified glassy carbon electrode for azo-colorants determination was investigated. Bismuth-film electrode (BiFE) was prepared by ex-situ depositing of bismuth onto glassy carbon electrode. The plating potential was −0.78 V (vs. SCE) in a solution of 0.15 mg mL−1 Bi(III) and 0.05 mg mL−1 KBr for 180 s. In the next step, a thin film of chitosan was deposited on the surface of bismuth modified glassy carbon electrode, thus the bismuth-chitosan thin film modified glassy carbon electrode (Bi-CHIT/GCE) was fabricated and compared with bare GCE and bismuth modified GCE. Azo-colorants such as Sunset Yellow and Carmoisine were determined on these electrodes by differential pulse voltammetry. Due to overlapping peaks of Sunset Yellow and Carmoisine, simultaneous determination of them is not possible, so net analyte signal standard addition method (NASSAM) was used for this determination. The results showed that coated chitosan can enhance the bismuth film sensitivity, improve the mechanical stability without caused contamination of surface electrode. The Bi-CHIT/GC electrode behaved linearly to Sunset Yellow and Carmoisine in the concentration range of 5×10−6 to 2.38×10−4 M and 1×10−6 to 0.41×10−4 M with a detection limit of 10 µM (4.52 µg mL−1) and 10 µM (5.47 µg mL−1), respectively

Generalized Net Analyte Signal Standard Addition as a Novel Method for Simultaneous Determination: Application in Spectrophotometric Determination of Some Pesticides

Simultaneous spectrophotometric determination of three neonicotinoid insecticides (acetamiprid, imidacloprid, and thiamethoxam) by a novel method named generalized net analyte signal standard addition method (GNASSAM) in some binary and ternary synthetic mixtures was investigated. For this purpose, standard addition was performed using a single standard solution consisting of a mixture of standards of all analytes. Savings in time and amount of used materials are some of the advantages of this method. All determinations showed appropriate applicability of this method with less than 5% error. This method may be applied for linearly dependent data in the presence of known interferents. The GNASSAM combines the advantages of both the generalized standard addition method and net analyte signal; therefore, it may be a proper alternative for some other multivariate methods.

Solubility and dissolution rate of a carbamazepine–cinnamic acid cocrystal

Synthesis of cocrystals is one of the methods to alter physicochemical properties of drugs. A cocrystal of carbamazepine (CBZ) and cinnamic acid (CIN) was synthesized using solvent evaporation and was characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FT-IR). The kinetic solubility, powder dissolution rate and stability of CBZ in aqueous solution were compared with those of cocrystal form (CBZ–CIN). Quantification of CBZ was evaluated using a UV-spectrophotometric technique in the presence of CIN that their spectrums are highly overlapped. Therefore, a recently developed net analyte signal standard addition method (NASSAM) was applied for determination of CBZ in the presence of CIN. The PXRD, DSC and FT-IR studies confirm that the cocrystal formation between CBZ and CIN and the developed NASSAM method can be used to quantitative determination of CBZ concentration in presence of CIN. The powder dissolution rate of cocrystal of CBZ–CIN is higher than CBZ and the kinetic solubility study show that the cocrystal is stable in dissolution medium and the aqueous solubility of CBZ–CIN is higher than CBZ. These findings show that formation of CBZ–CIN cocrystal is a suitable method to increase dissolution rate and solubility of CBZ and NASSAM is a valuable analytical method to quantitative determination of drugs in the presence of coformer in cocrystal studies.

Net analyte signal standard addition method for simultaneous determination of sulphadiazine and trimethoprim in bovine milk and veterinary medicines

Net analyte signal standard addition method has been used for the simultaneous determination of sulphadiazine and trimethoprim by spectrophotometry in some bovine milk and veterinary medicines. The method combines the advantages of standard addition method with the net analyte signal concept which enables the extraction of information concerning a certain analyte from spectra of multi-component mixtures. This method has some advantages such as the use of a full spectrum realisation, therefore it does not require calibration and prediction step and only a few measurements require for the determination. Cloud point extraction based on the phenomenon of solubilisation used for extraction of sulphadiazine and trimethoprim in bovine milk. It is based on the induction of micellar organised media by using Triton X-100 as an extraction solvent. At the optimum conditions, the norm of NAS vectors increased linearly with concentrations in the range of 1.0–150.0μmolL−1 for both sulphadiazine and trimethoprim. The limits of detection (LOD) for sulphadiazine and trimethoprim were 0.86 and 0.92μmolL−1, respectively.

Net Analyte Signal Standard Additions Method for Simultaneous Determination of Sulfamethoxazole and Trimethoprim in Pharmaceutical Formulations and Biological Fluids

The applicability of a novel net analyte signal standard addition method (NASSAM) to the resolving of overlapping spectra corresponding to the sulfamethoxazole and trimethoprim was verified by UV-visible spectrophotometry. The results confirmed that the net analyte signal standard additions method with simultaneous addition of both analytes is suitable for the simultaneous determination of sulfamethoxazole and trimethoprim in aqueous media. Moreover, applying the net analyte signal standard additions method revealed that the two drugs could be determined simultaneously with the concentration ratios of sulfamethoxazole to trimethoprim varying from 1:35 to 60:1 in the mixed samples. In addition, the limits of detections were 0.26 and 0.23 μmol L-1for sulfamethoxazole and trimethoprim, respectively. The proposed method has been effectively applied to the simultaneous determination of sulfamethoxazole and trimethoprim in some synthetic, pharmaceutical formulation and biological fluid samples.

Bismuth Modified Disposable Pencil‐Lead Electrode for Simultaneous Determination of 2‐Nitrophenol and 4‐Nitrophenol by Net Analyte Signal Standard Addition Method

AbstractA pencil‐lead electrode modified with a thin film of bismuth, that is “environmental friendlier” than mercury, was used for electrocatalytic reduction of 2‐nitrophenol (2‐NP) and 4‐nitrophenol (4‐NP) by differential pulse voltammetry and net analyte signal standard addition method (NASSAM). The modified electrode has electrocatalytic behavior toward reduction of 2‐NP and 4‐NP. Because of similar structures of analytes, at the modified electrode they have high overlapped signals that determination of them in the presence of each other is impossible with univariate methods. NASSAM is a very recently introduced method that is a new modification of the standard addition method, which was used for the simultaneous determination of 2‐NP and 4‐NP.

Application of Net Analyte Signal Standard Addition Method (NASSAM) for Simultaneous Determination of Lead and Tin by Differential Pulse Polarography

AbstractDifferential pulse polarography was used for simultaneous determination of Sn2+ and Pb2+. But there is a problem for simultaneous determination and it is high overlapped DPPs of mentioned cations that their determination is impossible in the presence of each other, so multivariate calibration methods as chemomatrics methods were used for this determination. There are some disadvantageous for multivariate calibration methods that can be solved by a new and simple method called net analyte signal standard addition method. This method has some advantages, such as: the use of a full voltammogram, realization in a single step, therefore it does not require calibration and prediction steps and only a few measurements are required for the determination.

Simultaneous Determination of Antazoline and Naphazoline by the Net Analyte Signal Standard Addition Method and Spectrophotometric Technique

A novel net analyte signal standard addition method (NASSAM) was used for simultaneous determination of the drugs anthazoline and naphazoline. The NASSAM can be applied for determination of analytes in the presence of known interferents. The proposed method is used to eliminate the calibration and prediction steps of multivariate calibration methods; the determination is carried out in a single step for each analyte. The accuracy of the predictions against the H-point standard addition method is independent of the shape of the analyte and interferent spectra. The net analyte signal concept was also used to calculate multivariate analytical figures of merit, such as LOD, selectivity, and sensitivity. The method was successfully applied to the simultaneous determination of anthazoline and naphazoline in a commercial eye drop sample.

Net analyte signal standard addition method (NASSAM) as a novel spectrofluorimetric and spectrophotometric technique for simultaneous determination, application to assay of melatonin and pyridoxine

In this work a new modification of the standard addition method called “net analyte signal standard addition method (NASSAM)” is presented for the simultaneous spectrofluorimetric and spectrophotometric analysis. The proposed method combines the advantages of standard addition method with those of net analyte signal concept. The method can be applied for the determination of analyte in the presence of known interferents. The accuracy of the predictions against H-point standard addition method is not dependent on the shape of the analyte and interferent spectra. The method was successfully applied to simultaneous spectrofluorimetric and spectrophotometric determination of pyridoxine (PY) and melatonin (MT) in synthetic mixtures and in a pharmaceutical formulation.

Net analyte signal standard addition method for the simultaneous determination of cadmium and nickel

A novel net analyte signal standard addition method (NASSAM) is presented for the simultaneous determination of Cd2+ and Ni2+ in their mixture by differential pulse polarography. The method combines the advantages of the standard addition method with the net analyte signal concept, which enables the extraction of information concerning a certain analyte from voltammograms of multi-component mixtures. This method has some advantages, such as: the use of a full voltammogram, realization in a single step, therefore it does not require calibration and prediction steps and only a few measurements are required for the determination. The simultaneous determination of Cd2+ and Ni2+ was performed in Britton-Robinson buffer (pH 2.87) and 0.40 M potassium thiocyanate solution.