Spectrophotometric Determination Research Articles

Спектрофотометрическое определение некоторых β-лактамных антибиотиков в их бинарных смесях с использованием метода проекций на латентные структуры

The method has been proposed for the spectrophotometric determination of antibiotics of the cephalosporin (cefuroxime, ceftriaxone, cefotaxime, cefazolin) and penicillin (amoxicillin) groups using chemometric data processing (method of partial least squares, PLS). The absorption spectra of 24 binary mixtures of “cephalosporin – cephalosporin” and 16 binary mixtures of “cephalosporin – amoxicillin” with various concentrations in the range of 3–27 and 5–140 μg/ml have been recorded. The optimal number of latent variables for each chemometric method (PLS-1 and PLS-2) has been selected, which ranged from 2 to 7 depending on the type of model and the nature of the antibiotics. The smallest root mean square calibration errors (RMSEC) have been found for the ceftriaxone–cefazolin system, which have been 0.09 and 0.08 for PLS-1 and PLS-2, respectively. The smallest root mean square errors of prediction (RMSEP) for the mixture “cefuroxime – amoxicillin” have been 0.07 for both methods (PLS-1 and PLS-2). It has been established that equations of linear relationships “measured-predicted” are characterized by a regression coefficient and the square of the approximation coefficient close to 1; which indicates the high quality of the models. The relative error of determination in test mixtures has been 0.4–6.2% by the PLS-1 method for “cephalosporin – cephalosporin” mixtures, and 0.07–6.0% by the PLS-2 method. At the same time, there is no significant difference in the error in determining the components of the mixture, in contrast to the “cefuroxime – amoxicillin” system, for which the error is 0.1–1.1% for the first component and 2.6–14.7% for the second component using the PLS-1 method and 0.2–1.2% for the first component and 4.3–13.3% for the second component using the PLS-2 method. Thus, it has been shown that the use of chemometric methods ensures high accuracy of the spectrophotometric determination of the studied antibiotics with overlapping absorption bands in their mixtures.

Spectrophotometric Analysis and Determination of Anti-inflammatory Effect of Punica granatum and Woodfordia fruticosa in Subjects With Chronic Periodontitis - A Randomized Controlled Clinical Trial.

Long-term use of chemical plaque control methods has led to adverse effects. In the current scenario, herbal mouthwashes have adequately remediated periodontal disease. Moreover, in the salivary interactome, biomarkers such as salivary amylase, a key protein secreted in the saliva, have been immensely useful in detecting the progression of periodontal disease. Therefore, we aimed to determine the anti-inflammatory effect of ethanolic crude extracts ofWoodordiafruticosaleaf andPunicagranatumpeel and to estimate salivary amylase levels in subjects diagnosed with chronic periodontitis. Ethanolic extracts of both plants were prepared using the soxhlet extraction method, and the obtained metabolites were confirmed by thin-layer chromatography. After a mouthwash was prepared, 100 subjects were randomly divided into two groups. Group I receivedPunicapeel (Pgp) mouthwash, and Group II receivedWoodfordialeaf (Wfl). Clinical parameters such as probing depth and clinical attachment loss were recorded to determine the grades of periodontitis. Unstimulated whole saliva was collected, and amylase levels were analyzed at three-time intervals using spectrophotometric assay. For both groups, the mean reduction in salivary amylase levels was calculated at baseline after 1 hour and 1 week of using the mouthwash. A statistically highly significant reduction was seen with (p=0.000*) at the 1-hr interval in Group I. The anti-inflammatory effect was more effective with Pgp mouthwash when compared to Wfl mouthwash.

Ultrasound assisted-cloud point extraction coupled with spectrophotometry for determination of low levels of formaldehyde from milk-based products

In this study, a preconcentration method is proposed for the separation, extraction and spectrophotometric determination of free formaldehyde (FA) from milk-based products. The method is based on ion-pair formation between phenoxazine 3-one, resazurin, and hydroxymethanesulfonate (HMS), which is selectively formed by the reaction of FA with sulfite at pH 5.0, followed by its extraction into the micellar phase of Triton X-114. Resazurin was adopted as ion-pairing reagent for detection of low levels of FA at 610nm. The variables affecting the extraction efficiency were evaluated and optimized. A linear relationship was obtained in the range of 2–120μgL-1 with a detection limit of 0.501μgL-1. Under optimum conditions such as pH 5.0, 8 µmol L-1 Resazurin, 0.4mgL-1 sulfide, 0.03% (v/v) of Triton X-114, after applying ultrasonic assisted-cloud point extraction (UA-CPE), spectrophotometric determination was made at 610nm to measure the concentration of FA found in trace amounts in milk-based products such as liquid, semi-solid and solid-milk products including whole milk, semi-skimmed milk, cacao milk, banana flavored milk, strawberry flavored milk, goat milk, yogurt, fruit flavored yogurt, white cheese. The precision was in the range 2.5-4.8% (n: 5, for 5, 25 and 100μgL-1). After preconcentration of a 15mL sample, a sensitivity enhancement factor of 55.6 was obtained. To represent the sample matrix, the validation was checked by intra-day/inter-day accuracy and precision analysis of a spiked quality control sample and its recoveries at three concentration levels. Finally, the method was successfully applied to the determination of free FA in samples, and recoveries in the range 90.8-97.4% with RSD lower than 5.7% after spiking were obtained.

Salt saturated dispersive liquid-liquid microextraction of crystal violet from fish and seawater samples based on camphor-thymol based hydrophobic deep eutectic solvent optimized by response surface methodology

A novel salt saturated dispersive liquid-liquid microextraction (SSDLLME) protocol is introduced for the extraction of crystal violet from fish and seawater samples prior to its spectrophotometric determination. As the extracting phase, a hydrophobic deep eutectic solvent based on camphor-thymol (by the mole ratio of 1:1) is employed in the sample. This is the first report of the application of SSDLLME for a dye utilizing deep eutectic solvents as extracting solvent. Saturation by salt significantly increased the performance of the microextraction; i.e. presence of salt in DLLME enhanced signals with more than 42%. Factors influencing the extraction efficiency were evaluated and optimized by both one-variable-at-a-time and response surface methodology methods. The optimum extraction condition were as: pH of sample solution 7.0; type and volume of extraction solvent (organic phase) 60 µL of camphor-thymol (1:1); 500 µL methanol as dispersive solvent; sample volume 10.0 mL; and time and rate of centrifugation 8 min and 9000 rpm, respectively. The suggested microextraction achieved a linear calibration curve in the concentration range of 1.0 to 500.0 µg L−1 with a limit of detection and quantification of 0.28 and 0.97 µg L−1, respectively. Recoveries were also suitable (≥0.97%). The total analysis time was less than 15 min and an enrichment factor of 157 was obtained. This is the first report on successful determination of crystal violet in Chabahar Bay (Oman Sea) and fishes live in the same area.

New spectrophotometric determination sulfamethoxazole drug via various analytical methods in pharmaceutical formulation

For the determination of sulfamethaxazole (SMZ) in pure and pharmaceutical formulations, new simple sensitive spectrophotometric methods have been devised. The first technique involved forming an ion pair complex between the basic nitrogen of the SMZ medication and Eriochrome black (EBT) in an acidic buffer solution, and extracting the created complex with chloroform to get a persistent reddish-orange colored dye with a maximum wavelength of 490 nm. Beer's law was followed, and 0.9998 was the correlation coefficient., 0.471×104L. mol-1.cm-1was the molar absorptivity, and the detection limit was 0.177 g/mL. Dispersive liquid-liquid extraction (DLLE) is a second method for estimating a trace amount in an aqueous solution product using an ion pair and a UV-visible spectrophotometer with a maximum wavelength of 490 nm. The concentration range was 0.5-6 g/mL, with a correlation coefficient of 0.9995, 0.889×105 L.mol-1.cm-1, a molar absorptivity of ,the detection limit of 0.013 g/L, and a pre-concentration factor of 25 and an enrichment factor of 18.20. Sulfamethaxazole in pharmaceutical formulations was successfully determined using the provided methodology
 

New spectrophotometric determination sulfamethaxazole drug via various analytical techniques in pharmaceutical formulation

The first method on the oxidative coupling Amoxixilin reaction with 2,4- dinitrophenyl hydrazine and Sodium Iodate diluted to produce a soluble red-Orange dye product was devised to estimate the Amoxicillin in bulk and pharmaceutical preparation. The concentration range is between 1 and 50 g/mL. Beer's law is met by the product in terms. With a molar absorptivity of 6.2×103L.mol-1.cm-1 and a correlation coefficient of 0.9995, Sandell's sensitivity is 0.059g.cm-2 at 475 nm. A second technique for determining a trace amount in an aqueous solution product is called cloud point extraction (CPE), and it is based on measurements made with a UV-visible spectrophotometer at a wavelength of 480 nm. The correlation coefficient was 0.9996 and the Beer's law concentration range was 0.25–6 g/mL The molar absorptivity was 103623.79 L.mol-1.cm-1. Pre-concentration 25, detection of limit 0.023 µg/mL. The distribution coefficient (D) was 158.6, and enrichment factor was 28.35. The last method is flow injection analysis, which is straightforward to estimate. The Beer's law concentration range was 2-150 µg / mL, Sandell's sensitivity is 0.13 µg.cm-2 at 475 nm, with a molar absorptivity of 2.8×103 L.mol-1.cm-1 and correlation coefficient was 0.9996, it is successfully used for drug estimation. Qualities in a straightforward situation or pharmacological formulations.
 
 
 

Serum trace element levels and activity of enzymes associated with oxidative stress in endometriosis and endometrial cancer.

Endometriosis and endometrial cancer are closely related to oxidative stress. However, the direct relationship between copper and zinc levels and oxidative stress in the extracellular and intracellular space remains unclear. The presented study is focused on the determination of serum Zn and Cu levels, glutathione concentration and enzyme activity in three groups: patients diagnosed with endometrial cancer (EC), patients diagnosed with endometriosis (EM), and a healthy control group. Spectrophotometric determination of trace elements revealed that levels of zinc and copper were lower in blood plasma of patients with endometriosis as compared with the other groups; however, there were no significant differences in the Cu/Zn ratio. Furthermore, significantly increased blood serum glutathione levels were detected in both EM and EC groups compared with the control group. While the activity of superoxide dismutase (SOD) was similar across the studied groups, we observed differences in the activity of other enzymes associated with oxidative stress, including glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST), between the control group and the EM and EC patients. Additionally, analysis of gene expression based on free circulating mRNA indicated significant differences in the expression of SOD isoenzymes between the patient groups and the control group; expression of GPx isoenzymes was also altered. Obtained results may have potential application in diagnostics as well as monitoring of endometriosis and endometrial cancer.

Fabrication of a Molecularly Imprinted Polymer Adsorbent for Pipette Tip Micro Solid-phase Extraction of Levofloxacin from Aqueous Samples Prior to its Spectrophotometric Determination

Aims: The main goal of this research was to find a simple, selective, sensitive and rapid protocol for the detection of traces of levofloxacin (Lev) in seawater, pills, urine, and human plasma samples by using a novel sorbent made of molecularly imprinted polymer (MIP) for its pipette-tip micro-solid phase extraction (PT-μSPE), followed by spectrophotometry. Parameters affecting the method were evaluated employing one-variable-at-a-time, Box-Behnken design (BBD) and central composite design (CCD) techniques, and results were compared together. Background: Lev, the active L-isomer isolated from racemic of loxacin, is a fluoroquinolone (FQ) antibiotic that is widely in use for curing infectious diseases due to its high activity against a large spectrum of both Gram-positive and Gram-negative bacteria. If it enters the environment, such as seawater, due to low degradation, it can remain there for the long term. Besides water, since Lev cannot be metabolized completely in the body, a selective and sensitive protocol for the analysis of Lev in biological fluids is necessary for physiological pharmacokinetics and clinical diagnosis. Objective: The objective was to find a fast, accurate and sensitive method for the determination of Lev in different sample matrices. This method should be very economical as well. Methods: This technique is based on using molecularly imprinted polymer adsorbent for pipette tip micro solid-phase extraction of Lev prior to its spectrophotometric detection. Results: The limit of detection of the developed protocol was 0.1 μg L-1, and its linear range was 1.0- 1,000.0 μg L-1 (R2=0.9934). The total time of analysis, including microextraction, was less than 10 min and for the analysis, a sample volume of 14 mL was adequate. 2.0 mg of the sorbent was sufficient for the extraction, and the sorbent could be reused for 4 times without loss in its extraction performance. For the spiked real samples at three levels, recoveries were in the range of 97.4% to 99.5%, with relative standard deviations better than 4.7%. Conclusion: The proposed protocol has advantages, including the simplicity of sorbent preparation and operation, consumption of a low amount of solvent and sorbent, which is in consistency with green chemistry, and high enrichment factor. In addition, it can be applied in samples with different matrices, has low analysis time (10 min), and uses inexpensive instruments.

A microextraction method for spectrophotometric determination of gold using benzalkonium chloride

A microextraction method for spectrophotometric determination of gold using benzalkonium chloride

Utility of N-Bromosuccinimide-Water Combination as a Green Reagents for a Validated Indirect Spectrophotometric Determination of Some Antihypertensive Drugs: An Application to Their Monitoring in Marketed Tablets and Capsules.

Analytical tests were conducted to investigate the use of N-bromosuccinimide (NBS) as an important, safe analytical reagent for the spectrophotometric detection of therapeutically significant dihydropyridine-based calcium antagonists (DHP), namely nifedipine (NIF) and amlodipine (AML), which have been demonstrated to possess antioxidant activity in vivo and to reduce the intracellular production of reactive oxygen species (ROS). Following the reaction of DHP and NBS in acidic media, the excess NBS was evaluated for the first time by its interaction with P-aminophenol (PAP), which produced a violet-colored product that was detected at 556 nm. The analytical method was performed and validated since different variables disturbing the reaction (concentration of reagent, type and concentration of the selected acid, reaction time and the diluting solvents) were carefully studied and optimized. The stoichiometry of the applied reaction was determined by Job's method of continuous variation. Monitoring of these drug dosage forms' content uniformity is a first tool or evidence for their efficacy and safety after their administration. Beer's law was obeyed in the concentration range 1.25-11.0 µg/mL for NIF and 1.25-10.0 µg/mL for AML. The calculated limit of detection (LODs) and limit of quantification (LOQs) for NIF and AML were 0.220, 0.155 µg/mL and 0.519, 0.735 µg/mL, respectively. The precision of the applied method was satisfactory; the RSDs did not exceed 2%. Two greenness assessment tools, the Green Analytical Procedure Index (GAPI) and Analytical Greenness Metric for Sample Preparation (AGREEprep) were used for measuring the environmental friendliness of the recommended method. The micro-determinations of content uniformity for NIF and AML in their pharmaceutical dosage forms were extremely comparable with those from official and validated procedures. A validated indirect spectrophotometric method for accurate quantification of some 1,4-dihydropyridine drugs using NBS with the aid of PAP. Monitoring of NIF and AML dosage forms' content uniformity as a first tool or evidence for their efficacy and safety after their administration. Greenness evaluation tools, GAPI and AGREEprep, for measuring the environmental friendliness of the recommended method.

Improving Determination of Pigment Contents in Microalgae Suspension with Absorption Spectroscopy: Light Scattering Effect and Bouguer-Lambert-Beer Law.

The Bouguer-Lambert-Beer (BLB) law serves as the fundamental basis for the spectrophotometric determination of pigment content in microalgae. Although it has been observed that the applicability of the BLB law is compromised by the light scattering effect in microalgae suspensions, in-depth research concerning the relationship between the light scattering effect and the accuracy of spectrophotometric pigment determination remains scarce. We hypothesized that (1) the precision of spectrophotometric pigment content determination using the BLB law would diminish with increasing nonlinearity of absorbance, and (2) employing the modified version of the BLB (mBLB) law would yield superior performance. To assess our hypotheses, we cultivated Phaeodactylum tricornutum under varying illumination conditions and nitrogen supplies in controlled indoor experiments, resulting in suspensions with diverse pigment contents. Subsequently, P. tricornutum samples were diluted into subsamples, and spectral measurements were conducted using different combinations of biomass concentrations and path lengths. This was carried out to assess the applicability of the BLB law and the nonlinearity of absorbance. The chlorophyll a and fucoxanthin contents in the samples were analyzed via high-performance liquid chromatography (HPLC) and subsequently used in our modeling. Our findings confirm our hypotheses, showing that the modified BLB law outperforms the original BLB law in terms of the normalized root mean square error (NRMSE): 6.3% for chlorophyll a and 5.8% for fucoxanthin, compared to 8.5% and 7.9%, respectively.

Spectrophotometric Determination of Acetamiprid Using Gold Nanoparticles (AuNPs) with Optimized Truncated Aptamers

Acetamiprid is mainly used to control pests. However, the residues of acetamiprid have resulted in significant negative effects on mammals. Many researchers are working on developing acetamiprid detection methods. In our study, four truncated aptamers were designed based on the secondary structure of the original aptamer. Molecular docking simulation of truncated aptamers confirmed that all of the truncated aptamers bind to acetamiprid, and their binding sites were identified. The affinity, sensitivity, and specificity of these truncated aptamers were measured by a spectrophotometric method with gold nanoparticles (AuNPs). Acetamiprid aptamers with 17-mer (Apt-J2) and 16-mer (Apt-J4) were successfully obtained, which show higher detection sensitivity and satisfactory specificity. Additionally, a spectrophotometric detection route superior to the original aptamer was explored, and the linear ranges were from 1 to 70 μM and 0.5 to 40 μM, respectively. The truncated aptamers were applied to the analysis of lake water, indicating that the aptamers have potential for practical analysis.

Selective separation and determination strategy for monitoring E100, E127, E129 and E133 in foodstuffs: Vortex assisted sequential-simultaneous liquid phase micro-extraction

A green, speedy and handy, vortex assisted sequential-simultaneous liquid phase micro-extraction procedure (VA-SS-LPME) was established first time without using any instrumental chromatographic techniques for separation, preconcentration and spectrophotometric determination of four important popularly and widely used food colorants, namely curcumin (E100), erythrosine (E127), allura red (E129) and brilliant blue (E133). Here, n-nonanol and n-nonanol based deep eutectic solvent were used as extraction solvents. The procedure has included two simultaneous and sequential separation steps by different extractants and two simultaneous UV–vis spectrophotometric determination steps. First, simultaneous separation of E100 and E127 from aqueous solution containing E129 and E133 was achieved and then simultaneous separation of E129 and E133 from aqueous solutions was applied and simultaneous spectrophotometric determinations were performed finally for binary mixture dyes (E100 and E127) and (E129 and E133). The parameters including pH, types and amounts of extractants, vortex time and rate, centrifugation time and rate were investigated in detail for sequential two steps separation and quantitative simultaneous extraction of the dyes. Interference effect of matrix ions, target and other dyes were examined. Possible envisaged extraction mechanisms were elucidated. Green analytical procedure index (GAPI) and analytical eco-scale (AES) parameters of the procedure were determined. As last, E100, E127, E129 and E133 contents of some foodstuffs and pharmaceuticals such as confectioneries, beverages, drugs and syrups were determined by applying optimized procedure. Colourful food additive concentrations of real samples were determined between 2.9 and 93.8 µg/g and 5.3–112.4 µg/mL for solid and liquid samples, respectively.

Absorbance Subtraction Method for the Determination of Losartan Potassium and Hydrochlorothiazide in Bulk and Tablets

A simple, accurate and precise method was proposed for the determination of losartan potassium and hydrochlorothiazide. The overlain spectra of losartan potassium and hydrochlorothiazide were found to have an isoabsorptive point at 266.9nm, while the spectrum of later is extended with an absorption maximum at 325 nm; where the former is not interfering, based on these spectral characteristics, simultaneous spectrophotometric determination of the two analytes in combined dosage was possible using absorbance subtraction method. The method showed good precision in term of repeatability and intermediate precision with relative standard deviations were less than 2% in both cases. The method’s accuracy was confirmed by the close agreement between the theoretical and actual concentrations of the analytes in nine laboratory prepared synthetic mixtures. The proposed method was successfully applied to the analysis of a commercial product, the assay results were 102.60% and 99.88%with %RSD 1.68 and 1.68for LSP and HCT, respectively.

IRON, HEME, AND NITROSYL-HEME CONTENT IN SPANISH MEAT DERIVATIVES

Heme and nitrosyl-heme have been pointed out as responsible for the association between processed meats and cancer. The objective of this study was to obtain reliable data on the current proximate composition, total iron, total heme, zinc-protoporphyrin, and nitrosyl-heme content in 40 meat derivatives consumed in Spain. The determination of heme and nitrosyl-heme was achieved using the classical spectrophotometric determination of the acetone extracts and compared with the chromatographic determination of these extracts which enables the separation of other porphyrins. Results revealed a high variability of heme and nitrosyl-heme contents in meat derivatives which may reflect differences in meat derivatives ingredients and formulations, manufacturing processes, storage, and cooking conditions. In addition, certain derivatives contain considerable amounts of nitrosyl-heme despite the fact there was no addition of nitrite or nitrate. Although the comparison of both methodologies for heme and nitrosyl-heme determination were in good agreement, the chromatographic method is advisable as some interfering compounds may lead to an overestimation when using the classical spectrophotometric determination. In the Spanish adult population and based on the obtained data the estimated total iron, nitrosyl-heme, and total heme intakes resulting from meat derivatives consumption, were 14.6mg/day, 528.6µg/day, and 1,676.2µg/day, respectively.

Design, spectral, molecular modeling, antimitotic, analytical and mechanism studies of phenyl isothiocyanate Girard's T derived metal complexes

The ligand N-{[(phenyl amino) thioxomethyl] hydrazino carbonyl methyl} trimethyl ammonium chloride (PTHAC) was prepared by the refluxing phenyl isothiocyanate and Girard-T (trimethyl ammonium-acethydrazide) in a molar ratio (1:1). The metal complexes derived from NiCl2.6H2O, CuCl2.2H2O and Co(CH3COO)2.6H2O were synthesized and purified. The PTHAC and its Cu(II), Co(II), and Ni(II) metal complexes(1–3) were characterized using a variety of various instrumental performances such as elemental analysis, magnetic moment, spectra (IR, UV–Vis, 1H NMR, mass) and thermal analysis (TGA and DTG).The results of element analysis, magnetic moment, spectra (IR, UV–Vis, 1H NMR, mass), and thermal (TGA and DTA) analyses provide the structures of the produced ligand and its (1–3) complexes. According to the spectroscopic results, PTHAC acts as an O, N and S tridentate donor, creating a mononuclear complex with copper(II), cobalt(II), and nickel(II) ions with an octahedral geometry. All of the atomic properties, including bond lengths, bond angles, HOMO, LUMO, dipole moments, and charges, have been determined. The cytotoxic activities of the PTHAC and the produced (1–3) complexes against breast carcinoma cells have been studied and correlated to the molecular modeling. When compared to the free ligand, CoII-L, and NiII-L, the CuII-L complex inhibits breast cancer cell growth more effectively. Furthermore, the PTHAC ligand was successfully applied for separation via flotation and spectrophotometric determination of Co(II) in several natural water, certified ore and pharmaceutical samples using oleic acid surfactant (HOL). At pH 6.5, PTHAC reacted with Co(II) to create a dark green (1:1) Co(II):PTHAC complex that was floated significantly using oleic acid (HOL) surfactant. The different experimental variable affecting the separation procedure e.g. pH, concentration of Co(II), HOL, PTHAC, temperature etc.…, were investigated. Co(II) had a linear range of (0.1–7.0) mgL−1. In the aqueous and scum layers, the molar absorptivities for the coloured complex are 0.14 × 104 and 0.16 × 105Lmol−1 cm−1, respectively. The LOD was 0.04 mgL−1, which is related to Sandell sensitivity of 3.7 × 10−3 µg cm−2 with a preconcentration factor of 200 and a RSD, % (n = 5) less than 4.2%. In addition, the mechanisms involved in the process of coordination of PTHAC with Cu(II), Co(II) and Ni(II) and the mechanism involved in the process of flotation of the PTHAC-Co(II) complex using HOL surfactant were elucidated.

Application of multivariate chemometrics tools for spectrophotometric determination of naphazoline HCl, pheniramine maleate and three official impurities in their eye drops

This work is concerned with exploiting the power of chemometrics in the assay and purity determination of naphazoline HCl (NZ) and pheniramine maleate (PN) in their combined eye drops. Partial least squares (PLS) and artificial neural network (ANN) were the chosen models for that purpose where three selected official impurities, namely; NZ impurity B and PN impurities A and B, were successfully determined. The quantitative determinations of studied components were assessed by percentage recoveries, standard errors of prediction as well as root mean square errors of prediction. The developed models were constructed in the ranges of 5.0–13.0 μg mL−1 for NZ, 10.0–60.0 μg mL−1 for PN, 1.0–5.0 μg mL−1 for NZ impurity B and 2.0–14.0 μg mL−1 for two PN impurities. The proposed models could determine NZ and PN with respective detection limits of 0.447 and 1.750 μg mL−1 for PLS, and 0.494 and 2.093 μg mL−1 for ANN. The two established models were compared favorably with official methods where no significant difference observed.

Reverse Flow Injection Spectrophotometric Determination of Total Acidity in Beverages Using Butterfly Pea Flower Extract.

Monitoring total acidity during beverage production is crucial for quality control (QC). The standard acid-base titration, though widely used, is slow and generates hazardous waste through the use of acid-base indicators. To develop an analysis method for beverage samples to determine total acidity using a natural reagent from butterfly pea flower as the colorimetric reagent. The determination of total acidity in beverages was based on the reaction of citric acid with anthocyanin extracted from butterfly pea flowers. The decreased absorbance of anthocyanin was measured at 620 nm. A two-line reverse flow injection manifold was used to perform online dilution of samples. Under optimal conditions, the calibration curve equation 1/A = 0.03782C + 0.00241 (A = absorbance and C = concentration) was linear over a range of 0.050-0.25% (w/v) citric acid. The LOD and LOQ were 0.0123 and 0.0409% (w/v), respectively. The system achieved a throughput of 120 samples per hour with comparable accuracy and precision to the standard titrimetric method. The injection of butterfly pea flower extract into beverage samples with online dilution in a reverse flow injection system (FIS) was reported for the first time for the determination of total acidity. Use of a green reagent in the method reflects its alignment with the principles of green analytical chemistry, providing a rapid and straightforward solution.

Spectrophotometric Determination of Ampicillin Using Chromogenic Reagents (MBTH and PDAC) and their Application in Pharmaceutical Formulations

The present work highlights the spectrophotometric method development and validation for the assay of ampicillin, a broad-spectrum β-lactam antibiotic. Two methods have been proposed by employing popular chromogenic reagents viz 3-methyl 2-benzothiazolinone hydrazone (MBTH) and para dimethyl amino cinnamaldehyde (PDAC). Method A involves the coupling of ampicillin with MBTH in the presence of ferric chloride through the oxidative mechanism, resulting in the formation of green coloured solution with a maximum absorption peak at 620 nm. In method B, the condensation reaction of ampicillin with an acidic solution of PDAC gave a coloured reddish-brown complex, showing a maximum absorption peak at 514nm. Linear calibration curve for MBTH and PDAC has been obtained while obeying Beer’s law in the concentration range of 0.5 -1 and 5-15 μg/ml having a good correlation coefficient of 0.9985 and 0.9974 respectively. The sensitivity of the submitted methods was found to be more than the reported methods. Both methods were successfully applied to a pharmaceutical formulation for quantifying the ampicillin effectively. Therefore, the developed spectrophotometric methods can serve as a good analytical assay procedure for ampicillin to undergo quality control in pharmaceutical setups.

Spectrophotometric Determination of Sulfanilamide Using Oxidative Coupling Reaction With the Presence of The Peroxidase Enzyme

Spectrophotometric Determination of Sulfanilamide Using Oxidative Coupling Reaction With the Presence of The Peroxidase Enzyme