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Journal articles on the topic 'First Derivative Zero Crossing Point Method'

Author: Grafiati

Published: 4 June 2025

Last updated: 1 August 2025

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1

Taulier, A., P. Levillain, and A. Lemonnier. "Determining methemoglobin in blood by zero-crossing-point first-derivative spectrophotometry." Clinical Chemistry 33, no. 10 (1987): 1767–70. http://dx.doi.org/10.1093/clinchem/33.10.1767.

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Abstract We determined methemoglobin in blood by zero-crossing-point first-derivative spectrophotometry. After lysis of erythrocytes, hemoglobin was converted into oxyhemoglobin and the first derivative spectrum was recorded between 405 and 425 nm. At the exact point where the first-derivative spectrum of oxyhemoglobin was zero ("zero-crossing point"), the first-derivative value of oxyhemoglobin and methemoglobin mixture was proportional to the methemoglobin concentration. The standard curve was linear for all proportions of methemoglobin. Within-assay precision (CV) was 3.4% for a 20% methemo

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2

Dudhrejiya, Ashvin, Ashok Patel, Jayant Chavda, Dhruvanshi Gol, and Priyal Koli. "Spectrophotometric simultaneous determination of efonidipine hydrochloride ethanolate and telmisartan in synthetic mixture by first order derivative method." Journal of medical pharmaceutical and allied sciences 11, no. 2 (2022): 4547–51. http://dx.doi.org/10.55522/jmpas.v11i2.2427.

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The established method represents the development and validation of a straight forward, precise, accurate, specific and reproducible method for the simultaneous estimation of Efonidipine Hydrochloride Ethanolate and Telmisartan in synthetic mixture. First order derivative of the overlay spectra was used for quantification of both drugs. This method involving the determination of both drugs at their respective zero crossing point working wavelength was observed 231.00 nm (Zero crossing point of Telmisartan) for Efonidipine hydrochloride ethanolate and 238.60 nm (Zero crossing point of Efonidipi

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3

Parmar, Kaminee, Sunil Baldania, Dimal Shah, Usmangani Chhalotiya, and Naimin Parmar. "Development and Validation of First-Order Derivative Spectrophotometry for Simultaneous Determination of Levocetirizine Dihydrochloride and Phenylephrine Hydrochloride in Pharmaceutical Dosage Form." International Journal of Spectroscopy 2013 (July 18, 2013): 1–6. http://dx.doi.org/10.1155/2013/502310.

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A simple, precise, accurate, and economical spectrophotometric method has been developed for simultaneous estimation of levocetirizine dihydrochloride (LCT) and phenylephrine hydrochloride (PHE) by employing first-order derivative spectrophotometric method. The first-order derivative absorption at 240 nm (zero crossing point of PHE) was used for quantification of LCT and 283.2 nm (zero crossing point of LCT) for quantification of PHE. The linearity was established over the concentration range of 4–24 μg/mL and 8–48 μg/mL for LCT and PHE with correlation coefficients (r2) 0.9964 and 0.9972, res

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4

Neeli, Sirisha, Haripriya Anuganti, Sathesh Babu R. Puvvadi, and Chavali VS Subrahmanyam. "First Derivative Synchronous Spectrofluorimetric Quantification of Telmisartan/Amlodipine Besylate Combination in Tablets." Dhaka University Journal of Pharmaceutical Sciences 12, no. 1 (2013): 35–40. http://dx.doi.org/10.3329/dujps.v12i1.16298.

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A first derivative synchronous spectrofluorimetric method has been developed and validated for simultaneous determination of telmisartan (TEL) and amlodipine besylate (AML) in combined tablet dosage form without any prior separation of components from the sample. TEL was determined at emission wavelength of 675 nm (zero-crossing wavelength point of AML). Similarly, AML was measured at 458 nm (zero-crossing wavelength point of TEL). The first derivative amplitude- concentration plots were rectilinear over the range of 4-14 ?g/ml for TEL and 1-6 ?g/ml for AML. The method was validated statistica

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Cielecka-Piontek, Judyta, Aran Lunzer, and Anna Jelińska. "Stability-indicating derivative spectrophotometry method for the determination of biapenem in the presence of its degradation products." Open Chemistry 9, no. 1 (2011): 35–40. http://dx.doi.org/10.2478/s11532-010-0125-9.

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AbstractA first-derivative UV spectrophotometric method, with or without the subtraction technique, was developed for the determination of biapenem in pharmaceutical dosage form in the presence of its degradation products. The method was based on the measurement of first-derivative amplitudes at zero crossing point (λ = 312 nm) and the peak-to-zero technique and validated with regard to linearity, limits of detection and quantitation, selectivity and precision. The observed rate constants for the degradation of biapenem were comparable to those obtained in the stability-indicating HPLC method.

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6

M. Patel, Shivani, and Lalit L. Jha. "SIMULTANEOUS UV METHOD DEVELOPMENT FOR DETERMINATION OF ROTIGOTINE HYDROCHLORIDE AND RASAGILINE MESYLATE." Indian Drugs 60, no. 05 (2023): 73–79. http://dx.doi.org/10.53879/id.60.05.13373.

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A precise, accurate analytical UV spectroscopic method has been developed for simultaneous estimation of rotigotine hydrochloride and rasagiline mesylate by using first order derivative spectroscopy. 50 µg mL-1 solutions of both drugs were scanned in the range of 200-800 nm and the first order overlain spectra of both drugs to check zero crossing points. Rotigotine hydrochloride showed zero crossing point at 239 nm where and rasagiline mesylate showed at 273 nm. Six-point calibration curves shown linearity in 2-12 µg mL-1 concentration range for rotigotine hydrochloride and 10-60 µg mL-1 conce

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Wani, Rakesh M., Arun M. Kashid, Amita Ghatge, and Sumita Sahoo. "SIMULTANEOUS ESTIMATION OF ASPIRIN AND OMEPRAZOLE IN LABORATORY SAMPLE BY DIFFERENT UV SPECTROPHOTOMETRIC TECHNIQUES." INDIAN DRUGS 57, no. 09 (2020): 75–81. http://dx.doi.org/10.53879/id.57.09.11417.

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The aim of the present work was to develop simple, precise and economic UV- spectrophotometric methods for the simultaneous estimation of aspirin and omeprazole in a laboratory sample. The absorbance maxima (λmax) for detection of aspirin and omeprazole were selected as 274 nm and 302 nm, respectively, for simultaneous equation method while wavelength range for detection of aspirin and omeprazole were selected as 270 nm - 276 nm and 300 nm - 305 nm, respectively for area under curve method. Absorbance ratio method uses the ratio of absorbances at two selected wavelengths, one which is an isoab

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8

Patil, T. N., S. D. Firke, S. B. Bari, N. S. Joshi, and P. S. Bafna. "SIMULTANEOUS ESTIMATION OF EBASTINE AND MONTELUKAST SODIUM IN TABLET DOSAGE FORM BY UV-SPECTROPHOTOMETRY AND FIRST ORDER DERIVATIVE." INDIAN DRUGS 50, no. 10 (2013): 47–52. http://dx.doi.org/10.53879/id.50.10.p0047.

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A simple, precise, accurate and reproducible spectrophotometric method has been developed for simultaneous estimation of ebastine and montelukast sodium by employing first order derivative zero crossing method in methanol and water. The first order derivative absorption at 234 nm (zero cross point of ebastine) was used for quantification of montelukast sodium and 281.60 nm (zero cross point of montelukast sodium) for quantification of ebastine. The linearity was established over the concentration range of 5-25 μg/mL for both ebastine and montelukast sodium with correlation coefficient r2 0.997

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9

Gómez, Iban, Ester Viteri, Jessica Montero, Mile Djurdjevic, and Gerhard Huber. "The Determination of Dendrite Coherency Point Characteristics Using Three New Methods for Aluminum Alloys." Applied Sciences 8, no. 8 (2018): 1236. http://dx.doi.org/10.3390/app8081236.

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The aim of this work is to give an overview of existing methods and to introduce three new methods for the determination of the Dendrite Coherency Point (DCP) for AlSi10Mg alloys, as well as to compare the acquired values of DCP based on a thermal analysis and on the analysis of cooling curves working with only one thermocouple. Additionally, the impact of alloying and contaminant elements on the DCP will be also studied. The first two proposed methods employ the higher order derivatives of the cooling curves. The DCP was determined as the crossing point of the second and third derivative curv

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Prajapati, Krishna V., Hasumati A. Raj, Vineet C. Jain, and Neelam S. Prajapati. "FIRST DERIVATIVE SPECTROSCOPIC METHOD FOR SIMULTANEOUS ESTIMATION OF MESALAZINE AND RIFAXIMIN IN SYNTHETIC MIXTURE." Pharmaceutical and Biological Evaluations 3, no. 2 (2016): 231–40. https://doi.org/10.5281/zenodo.51068.

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Objective: The present study was aimed to describe a simple, sensitive, rapid, accurate, precise and economical first derivative spectrophotometric method for the simultaneous determination of Mesalazine (MESA) and Rifaximin (RIFA) in synthetic mixture. Methods: The derivative spectrophotometric method was based on the determination of both the drugs at their respective zero crossing point (ZCP). The first order derivative spectra were obtained in 0.01 N NaOH and the determinations were made at 329.20 nm (ZCP of RIFA) for MESA and 292.80 nm (ZCP of MESA) for RIFA. The linearity was obtained in

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11

Raskar, Manish A., Shweta S. Mungse, Prajkta A. Kate, and Ganesh Raosaheb Godge. "Validated Simultaneous Derivative Spectrophotometric Estimation of Diflunisal and Lignocaine in Bulk and Pharmaceutical Formulation." Journal of Drug Delivery and Therapeutics 13, no. 8 (2023): 51–55. http://dx.doi.org/10.22270/jddt.v13i8.6166.

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Two simple, sensitive, accurate and precise spectrophotometric methods were developed and validated for the quantitative determination of Diflunisal (DIF) and Lignocaine (LIG) in bulk and pharmaceutical dosage form. Method A is based on the first-order derivative (D1), and Method B is based on the second-order derivative (D2) spectrophotometric method. In Method A, absorbance was measured at 224nm and 264nm being the zero crossing points for DIF and LIG, respectively. In Method B, absorbance was measured at 232nm and 273nm being the zero crossing points for DIF and LIG, respectively. For Metho

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12

Youssef, Rasha M. "Validated Stability-Indicating Methods for the Determination of Nizatidine in the Presence of Its Sulfoxide Derivative." Journal of AOAC INTERNATIONAL 91, no. 1 (2008): 73–82. http://dx.doi.org/10.1093/jaoac/91.1.73.

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Abstract Four new selective, precise, and accurate methods are described for the determination of nizatidine (NIZ) in the presence of its sulfoxide derivative in both the raw material and pharmaceutical preparations. Method A is based on zero-order (0D), first-derivative (1D), and second-derivative (2D) spectrophotometric measurement of NIZ in aqueous solution at the zero-crossing point of its sulfoxide derivative (at 314, 295334, and 318348 nm, respectively). Method B is a 1DD spectrophotometric method based on the simultaneous use of the first derivative of the ratio spectra and the measurem

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13

D.NAGAVALLI and R.SHANMUGAVEL. "Simultaneous Equation, Absorbance Ratio and First Order Derivative Methods for the Estimation of Atorvastatin Calcium and Fenofibrate in Solid Dosage Form." International Journal of Innovative Science and Research Technology 8, no. 2 (2023): 457–61. https://doi.org/10.5281/zenodo.7659258.

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Three simple, precise, accurate, specific and reproducible spectrophotometric methods, requiring no prior separation, have been developed for the simultaneous estimation of atrovastatin calcium (ATV) and fenofibrate (FEN) in combined dosage form. Quantitative estimation of these drugs in marketed brands of the tablet was carried out using simultaneous equation, absorbance ratio and first order derivative methods. In the simultaneous equation method ATV and FEN have absorbance maxima at 247 and 289 nm respectively in methanol. Second method employs Q absorbance analysis using 254 nm (Isobestic

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14

Prasad, Challapalli V. N., Vipin Bharadwaj, Vidya Narsimhan, Rama T. Chowdhary, and Pyare Parimoo. "Simultaneous Determination of Metoprolol-Hydrochlorothiazide and Propranolol-Hydrochlorothiazide in Combined Formulations by Derivative Spectroscopy." Journal of AOAC INTERNATIONAL 80, no. 2 (1997): 325–30. http://dx.doi.org/10.1093/jaoac/80.2.325.

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Abstract A derivative spectrophotometric procedure was established for simultaneous determination of propranolol HCI (PP) with hydrochlorothiazide (HTZ) and metoprolol tartrate (MTP) with HTZ in tablet preparations. The method uses first- and second-derivative spectra of tablet extract in 0.01 N NaOH solution. Ratios of analyte concentrations in the mixture were determined by the compensation technique. The zero-crossing point (ZCP) was also used to estimate the amounts of PP and HTZ in the formulations, and results were compared with those from the compensation technique. The results were fou

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15

Mehta, Pratik S., Pratik R. Patel, Rajesh R. Parmar, M. M. K. Modasiya, and Dushyant A. Shah. "Development and Validation of Derivative Spectroscopic Method for Simultaneous Estimation of Cefadroxil and Probenecid." International Journal of Pharmaceutical Sciences and Nanotechnology 7, no. 1 (2014): 2350–55. http://dx.doi.org/10.37285/ijpsn.2014.7.1.6.

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A novel, simple, accurate, sensitive, precise and economical derivative spectroscopic method was developed and validated for the determination of cefadroxil and probenecid in synthetic mixture. First order derivative spectroscopy method was adopted to eliminate spectral interference. The method obeys Beer’s Law in concentration ranges of 4-36 μg/ml for cefadroxil and of 5-25 μg/ml of probenecid. The zero crossing point for cefadroxil and probenecid was 260 nm and 237.8 nm respectively in 0.1N HCl. The method was validated in terms of accuracy, precision, linearity, limits of detection, limits

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Issa, Mahmoud Mohamed, R'afat Mahmoud Nejem, Alaa Abu Shanab, and Raluca-Ioana Stefan-van Staden. "Resolution of Ternary Mixture of Aspirin, Atorvastatin, and Clopidogrel by Chemometric-Assisted UV Spectroscopic and Liquid Chromatography Methods." International Journal of Spectroscopy 2013 (September 22, 2013): 1–8. http://dx.doi.org/10.1155/2013/726820.

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Two chemometrics-assisted UV spectrophotometric methods were proposed for the resolution of ternary mixtures without any chemical pretreatment. The first method is based on modification of H-point standard addition method which permits simultaneous analysis of three species from a unique calibration set by making the simultaneous addition of the three analytes. Quotient between the spectra of aspirin, atorvastatin, and clopidogrel was obtained and the results showed that simultaneous determination of aspirin, atorvastatin, and clopidogrel can be obeyed in the linear range 2.5–20 μg mL−1 of asp

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17

Raskar, M. A., P. A. Kate, S. S. Mungse, and Ganesh Raosaheb Godge. "Validated Simultaneous Derivative Spectrophotometric Estimation of Azithromycin, Fluconazole and Secnidazole in Bulk and Pharmaceutical Formulation." Journal of Drug Delivery and Therapeutics 13, no. 11 (2023): 39–44. http://dx.doi.org/10.22270/jddt.v13i11.6286.

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Two simple, sensitive, accurate and precise spectrophotometric methods were developed and validated for the quantitative determination of Azithromycin (AZI), Fluconazole (FLU) and Secnidazole (SEC) in bulk and tablet dosage form. Method A is based on the first-order derivative (D1) and Method B is based on the second-order derivative (D2) spectrophotometric method. In Method A, absorbance was measured at 215nm, 275nm and 333nm being the zero crossing points for AZI, FLU and SEC respectively. In Method B, absorbance was measured at 220nm, 225nm and 211nm being the zero crossing points for AZI,

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18

Shi, Xue Chao, Zhen Zhong Sun, and Sheng Lin Lu. "A Novel Method of Sub-Pixel Linear Edge Detection Based on First Derivative Approach." Advanced Materials Research 139-141 (October 2010): 2107–11. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.2107.

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In this paper, a novel algorithm is proposed to detect linear edge. Image gradient is acquired by Sobel or Prewitt filters. Logical addition is applied to enhance image contrast. Statistical method is employed to cope with gradient data—gradient projection in the horizontal and vertical direction to compute the average gradient value. Multi-level B-Spline interpolation is employed to smooth gradient data. At last, edge coordinates can be computed precisely by the number and interval of extreme points. The experiment results are presented to show validity of the algorithm, which precision and a

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Jenisha, Patel, Patel Grishma, and Meshram Dhananjay. "Development and Validation of UV and RP-HPLC Methods for Simultaneous Estimation of Mirabegron and Solifenacin Succinate in Their Pharmaceutical Dosage Form." International Journal of Pharmaceutical and Bio-Medical Science 02, no. 08 (2022): 223–32. https://doi.org/10.5281/zenodo.6948597.

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Recently, a new formulation containing Mirabegron (MB) and Solifenacin succinate (SFS) has been approved for the management of over active bladder. However, only one analytical method has been reported for the simultaneous determination of both the analytes. Therefore, the current study was design to develop simple UV derivative spectroscopic and rapid RP-HPLC methods for simultaneous determination of MB and SFS. The chromatographic separation of MB and SFS was performed using Phenomenex Kinetex C<sub>18</sub> (150mm × 4.5 mm × 5 µm) analytical column. A mixture of Water: Ace

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Priti, R. Kale1 Vishal B. Babar2 Ashish B. Jadhav3. "Analytical Method Validated Techniques For The Simultaneous Estimation Of Olmesartan Medoxomil And Ramipril By RP-HPLC Method." International Journal in Pharmaceutical Sciences 2, no. 1 (2024): 13–22. https://doi.org/10.5281/zenodo.10450799.

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A reverse phase high performance liquid chromatopgraphic simultaneous estimation  (HPLC) was developedand validated as per ICH 2019, US FDA 2018 guidelines for quantification of Ramipril (RAM) and Olmesartan Medoxomil.  In present study, Estimatimation  of Olmesartan Medoxomil (OLM) and Ramipril (RAM) in tablet formulation,  accurate, and affordable approach has been established. Both OLM and RAM are angiotensin-converting enzyme inhibitors, which are antihypertensive drugs. The combination of Ramipril (RAM) and Olmesartan Medoxomil (ATV) in Telmy-R is a particularly effect

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Patel, Satish A., Arun M. Prajapati, Paresh U. Patel, Natubhai J. Patel, and Jayesh B. Vaghmasi. "Development and Validation of Column High-Performance Liquid Chromatographic and Derivative Spectrophotometric Methods for Determination of Levofloxacin and Ornidazole in Combined Dosage Forms." Journal of AOAC INTERNATIONAL 91, no. 4 (2008): 756–61. http://dx.doi.org/10.1093/jaoac/91.4.756.

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Abstract The manuscript describes validated reversed-phase column high-performance liquid chromatographic (RP-HPLC) and first-derivative UV spectrophotometric methods for the estimation of levofloxacin (LFX) and ornidazole (ORNI) in combined dosage forms. The RP-HPLC separation was achieved on a Phenomenex C18 column (250 mm 4.6 mm id, 5 m) using KH2PO4 buffer (pH 6.8)methanolacetonitrile (70 + 15 + 15, v/v/v) mobile phase at a flow rate of 1.5 mL/min and ambient temperature (25 2&lt;sup/&gt;C). Quantification was achieved with photodiode array detection at 295 nm over the concentratio

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Abdel-Fattah, Laila S., Zeinab A. El-Sherif, Khadiga M. Kilani, and Dalia A. El-Haddad. "HPLC, TLC, and First-Derivative Spectrophotometry Stability-Indicating Methods for the Determination of Tropisetron in the Presence of Its Acid Degradates." Journal of AOAC INTERNATIONAL 93, no. 4 (2010): 1180–91. http://dx.doi.org/10.1093/jaoac/93.4.1180.

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Abstract Three stability-indicating assay methods were developed for the determination of tropisetron in a pharmaceutical dosage form in the presence of its degradation products. The proposed techniques are HPLC, TLC, and first-derivative spectrophotometry (1D). Acid degradation was carried out, and the degradation products were separated by TLC and identified by IR, NMR, and MS techniques. The HPLC method was based on determination of tropisetron in the presence of its acid-induced degradation product on an RP Nucleosil C18 column using methanolwateracetonitriletrimethylamine (65 + 20 + 15 +

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Savani, Pankaj, Sudhanshu Chauhan, Vineet Jain, Hasumati Raj, and Sagar Patel. "DEVELOPMENT AND VALIDATION OF ANALYTICAL METHOD FOR CLOPIDOGREL BISULPHATE AND IRBESARTAN BY SIMULTANEOUS EQUATION SPECTROSCOPIC METHOD." Pharmaceutical and Biological Evaluations 3, no. 2 (2016): 215–23. https://doi.org/10.5281/zenodo.51065.

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Objective: The major approach take into consideration is to develop a simple, accurate, precise and reproducible method for development and validation of UV-visible spectrophotometric method for estimation of Clopidogrel Bisulphate and Irbesartan in synthetic mixture. Methods: In linearity spectra of the Clopidogrel Bisulphate and Irbesartan to shows to possible a simultaneous equation method but the zero order linearity spectra was converted to first derivative and second derivative spectroscopic method to not shows any zero crossing point so that this method was not possible. Results: In thi

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Attimarad, Mahesh, Muhammad Shahzad Chohan, Venugopala Katharigatta Narayanaswamy, et al. "Mathematically Processed UV Spectroscopic Method for Quantification of Chlorthalidone and Azelnidipine in Bulk and Formulation: Evaluation of Greenness and Whiteness." Journal of Spectroscopy 2022 (May 20, 2022): 1–13. http://dx.doi.org/10.1155/2022/4965138.

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A simple, eco-friendly four analytical methods were established by improving the selectivity through the application of mathematical processing of UV absorption spectra for concurrent quantification of chlorthalidone (CTL) and azelnidipine (AZE). The UV absorption spectra were recorded using environment-friendly ethanol (10% v/v) and were mathematically processed using simple software provided with a UV spectrophotometer. The analytes’ peak amplitude was determined using zero-crossing point first derivative spectra and ratio first derivative spectra of CTL and AZE, which were measured at 238.5

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Dinçel, Aysun, Elif Gök-Topak, and Feyyaz Onur. "Simultaneous determination of emtricitabine and tenofovir disoproxil fumarate in pharmaceutical preparations using spectrophotometric, chemometric and chromatographic methods." Journal of the Serbian Chemical Society, no. 00 (2024): 31. http://dx.doi.org/10.2298/jsc230909031d.

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Simple, accurate and sensitive spectrophotometric, chemometric and chromatographic methods were used for the simultaneous determination of emtricitabine (ETC) and tenofovir disoproxil fumarate (TDF) in tablets. In 1st derivative spectrophotometry, first derivative spectra of the solution of ETC and TDF in water were recorded as ?? = 4 nm and first derivative absorbances were measured at the zero-crossing points at 297.3 nm and 281.2 nm for ETC and TDF respectively. In ratio 1st derivative spectrophotometry measurements were recorded at 239.0 nm and 270.2 nm for ETC and TDF respectively. Then a

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Chauhan, Sudhanshu, Pankaj Savani, Hasumati Raj, Sagar Patel, Vineet Jain, and Neelam Prajapati. "Development and validation of first order derivative spectroscopy method for simultaneous estimation of candesartan cilexetil and pioglitazone hydrochloride in synthetic mixture." Pharmaceutical and Biological Evaluations 3, no. 2 (2016): 264–71. https://doi.org/10.5281/zenodo.51076.

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Objective: Objective of the study was to develop a simple, accurate, precise, economic, robust and rugged UV spectrophotometric method and validate for the simultaneous estimation of Candesartan Cilexetil and Pioglitazone Hydrochloride in synthetic mixture. Methods: Combination of Candesartan Cilexetil and Pioglitazone Hydrochloride has only one LC-MS/MS analytical method developed yet, so this UV method was novel for combined synthetic dosage of Candesartan Cilexetil and Pioglitazone Hydrochloride (1:2). This method utilizes methanol as a solvent. Zero crossing point (ZCP) of Candesartan Cile

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Mashru, Rajashree, and Nirupa Koshti. "Development and validation of UV-Spectrophotometric and RP-HPLC method for simultaneous estimation of Metformin and Doxycycline in bulk and synthetic mixture." Journal of Drug Delivery and Therapeutics 11, no. 4-S (2021): 26–35. http://dx.doi.org/10.22270/jddt.v11i4-s.4964.

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A simple, rapid, sensitive, accurate and precise UV spectrophotometric and isocratic RP-HPLC method have been developed for simultaneous estimation of Metformin and Doxycycline in bulk and synthetic mixture. Spectrophotometric estimation was done by two methods. First method was Q-absorbance ratio method, where two wavelengths 236 nm (λmax of Metformin) and 248 nm (Iso-absorptive point) were used. The second method was first derivative method. In this method the zero-crossing point of Metformin was selected at 282 nm and for Doxycycline, it was 232 nm. The solvent used was methanol in both the

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Patel, Mehul, Bhavna Patel, and Shraddha Parmar. "Simultaneous Estimation of Ibuprofen and Phenylephrine Hydrochloride in Bulk and Combined Dosage Form by First Derivative UV Spectrophotometry Method." Journal of Spectroscopy 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/364750.

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A simple, precise, rapid, and economic method was developed for the simultaneous determination of Ibuprofen and Phenylephrine HCl in bulk and combined dosage form. This method involves first-order derivative spectroscopy using 248 nm and 237 nm as zero crossing points for Ibuprofen and Phenylephrine HCl, respectively. For spectrophotometric method 0.1 N NaOH was used as a solvent. The linearity was established over the concentration range of 12–72 μg/mL and 1.5–22 μg/mL for Ibuprofen and Phenylephrine HCl with correlation coefficient (r2) of 0.9972 and 0.9981, respectively. The mean % recoveri

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Sarkis, Nazira, and Abdulkader Sawan. "Method Development for Simultaneously Determining Indomethacin and Nicotinamide in New Combination in Oral Dosage Formulations and Co-Amorphous Systems Using Three UV Spectrophotometric Techniques." International Journal of Analytical Chemistry 2024 (February 20, 2024): 1–14. http://dx.doi.org/10.1155/2024/2035824.

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This research aims to develop methods for simultaneously determining indomethacin (IND) and nicotinamide (NCT) in binary mixtures, immediate-release capsules, sustained-release capsules, and co-amorphous systems, which were designed in 2021 to improve the solubility, dissolution rate, and stability of the amorphous state of indomethacin. Moreover, this new combination may have also other possible medical benefits. Therefore, there is a need to have simple, sensitive, and precise developed methods for simultaneous quantification analysis of IND/NCT in several different ratios. Three UV-spectrop

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Monsores, Millena Almeida, Mikaelly Pereira Caet, Anna Karolina Mouzer Machado, Marina Cardoso Nemitz, Vítor Todeschini, and Maximiliano Da Silva Sangoi. "Validation of a green spectrophotometric method for the determination of dropropizine in commercial oral solutions." Drug Analytical Research 4, no. 2 (2020): 12–18. http://dx.doi.org/10.22456/2527-2616.108127.

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The present work describes a first-order derivative spectrophotometric (1D-UV) method for determination of dropropizine in commercial oral solutions. The method was developed using ecologically correct solvents and validated according to International Conference on Harmonization (ICH) recommendations. The response was linear in the concentration range of 6–24 μg/mL (r = 0.9997, n = 7) at wavelength 249 nm, which was the zero crossing point of excipient solutions. The detection and quantitation limits were 0.36 and 1.18 μg/mL, respectively. The method showed adequate precision, with a relative

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Abo El Abass, Samah, and Heba Elmansi. "Synchronous fluorescence as a green and selective tool for simultaneous determination of bambuterol and its main degradation product, terbutaline." Royal Society Open Science 5, no. 10 (2018): 181359. http://dx.doi.org/10.1098/rsos.181359.

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A green, sensitive and cost-effective method is introduced in this research for the determination of bambuterol and its main degradation product, terbutaline, simultaneously, relying on the synchronous spectrofluorimetric technique. First derivative synchronous spectrofluorimetric amplitude is measured at Δ λ = 20 nm, so bambuterol can be quantitated at 260 nm, and terbutaline can be measured at 290 nm, each at the zero crossing point of the other. The amplitude–concentration plots were linear over the concentration ranges of 0.2–6.0 µg ml −1 and 0.2–4.0 µg ml −1 for both bambuterol and terbut

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El-Maraghy, Christine M., and Ekram H. Mohamed. "Successive Stability Indicating Spectrophotometric Technique for Simultaneous Determination of Quetiapine Fumarate and its Three Major Related Compounds." Current Analytical Chemistry 16, no. 4 (2020): 447–55. http://dx.doi.org/10.2174/1573411014666180709145526.

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Background: Quetiapine Fumarate (QTF) is an atypical antipsychotic drug used to treat mental disorders as depression and schizophrenia. The analysis of the dug in the presence of its precursors, degradants and impurities without interference represents a challenge for the analysts. The regulatory requirements recommended by ICH stated that the impurities above or equal to 0.1% must be identified, characterized and determined. The aim of this work was to introduce three smart and selective spectrophotometric methods that could resolve the complete overlapping of QTF drug with its three related

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Zhou, Fengbo, Bo Wu, and Jianhua Zhou. "Novel Spectrophotometric Method for Robust Detection of Trace Copper and Cobalt in High-Concentration Zinc Solution." Molecules 29, no. 23 (2024): 5765. https://doi.org/10.3390/molecules29235765.

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In the purification process of zinc hydrometallurgy, the spectra of copper and cobalt seriously overlap in the whole band and are interfered with by the spectra of zinc and nickel, which seriously affects the detection results of copper and cobalt in zinc solutions. Aiming to address the problems of low resolution, serious overlap, and narrow characteristic wavelengths, a novel spectrophotometric method for the robust detection of trace copper and cobalt is proposed. First, the Haar, Db4, Coif3, and Sym3 wavelets are used to carry out the second-order continuous wavelet transform on the spectr

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Attimarad, Mahesh, Katharigatta N. Venugopala, Bandar E. Al-Dhubiab, Rafea Elamin Elgack Elgorashe, and Sheeba Shafi. "Development of Ecofriendly Derivative Spectrophotometric Methods for the Simultaneous Quantitative Analysis of Remogliflozin and Vildagliptin from Formulation." Molecules 26, no. 20 (2021): 6160. http://dx.doi.org/10.3390/molecules26206160.

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Three rapid, accurate, and ecofriendly processed spectrophotometric methods were validated for the concurrent quantification of remogliflozin (RGE) and vildagliptin (VGN) from formulations using water as dilution solvent. The three methods developed were based on the calculation of the peak height of the first derivative absorption spectra at zero-crossing points, the peak amplitude difference at selected wavelengths of the peak and valley of the ratio spectra, and the peak height of the ratio first derivative spectra. All three methods were validated adapting the ICH regulations. Both the ana

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Chohan, Muhammad Shahzad, Mahesh Attimarad, Katharigatta Narayanaswamy Venugopala, et al. "Sensitivity Enhanced Ecofriendly UV Spectrophotometric Methods for Quality Control of Telmisartan and Benidipine Formulations: Comparison of Whiteness and Greenness with HPLC Methods." International Journal of Environmental Research and Public Health 19, no. 12 (2022): 7260. http://dx.doi.org/10.3390/ijerph19127260.

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The development of an environmentally friendly analytical technique for simultaneous measurement of medicines with large concentration differences is difficult yet critical for environmental protection. Hence, in this work, new manipulated UV-spectroscopic methods with high scaling factors were established for concurrent quantification of telmisartan (TEL) and benidipine (BEN) in fixed-dose combinations. Two different methods were developed and established by calculation of peak height at zero crossing point of second derivative and the ratio of first derivative spectra with a scaling factor o

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Sharma, Monika, Diksha Gulati, Anjoo Kamboj, and Saahil Arora. "Simultaneous Estimation of Curcumin and Gentamicin by UV-VIS Spectrometric Methods or Derivative Spectroscopic Techniques." Biomedical and Pharmacology Journal 16, no. 4 (2023): 2283–91. http://dx.doi.org/10.13005/bpj/2804.

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A simultaneous study is very important analytical parameter which helps to assess compatibility of mixture of drugs. UV spectrophotometer is one of the simplest and efficient methods to assess simultaneous parameters. Due to its economical approach, we have used UV spectrophotometer. Curcumin and Gentamicin sulphate have zero crossing points of 420 nm and 244 nm, respectively, in first-order derivative spectroscopy. The solvent for the spectrophotometric process was 0.1 N NaOH. Curcumin and Gentamicin sulphate linearity was established over range of concentrations of 2–12 g/ml, with correlatio

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Sianipar, Artha Yuliana, Muchlisyam Muchlisyam, and Siti Morin Sinaga. "APPLICATION AND VALIDATION OF DERIVATIVE SPECTROPHOTOMETRIC FOR DETERMINATION LEVELS OF TERNARY MIXTURES OF PARACETAMOL, PROPYPHENAZONE, AND CAFFEINE IN TABLET DOSAGE FORM." Asian Journal of Pharmaceutical and Clinical Research 11, no. 13 (2018): 8. http://dx.doi.org/10.22159/ajpcr.2018.v11s1.26553.

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Objective: This study was to develop a spectrophotometric method with derivative zero-crossing for determines the levels of paracetamol (PCT), propyphenazone (PRO), and caffeine (CAF) in tablet dosage form without prior separation.Method: The study begins with optimizing the type of solvent, phosphate buffer (pH 7.2) and a mixture of phosphate buffer (pH 7.2) with methanol at ratio 90:10; 70:30; 50:50; 30:70; and 10:90. Spectrophotometric method with zero-crossing, tested validity based on linearity, accuracy, precision, limit of detection, and limit of quantification. Then, the method applied

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Kowalczuk, Dorota, and Hanna Hopkała. "Application of Derivative Spectrophotometry for Simultaneous Determination of Quinapril and Hydrochlorothiazide in the Combination Tablets." Journal of AOAC INTERNATIONAL 87, no. 4 (2004): 847–51. http://dx.doi.org/10.1093/jaoac/87.4.847.

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Abstract A new second-order-derivative spectrophotometric method using zero-crossing technique measures quinapril (QUI) and hydrochlorothiazide (HYD) in 2-component mixtures. The procedure does not require prior separation of components from the sample. QUI was determined at a wavelength of 211.6 nm (zero-crossing wavelength point of HYD). Similarly, HYD was measured at 270.8 nm (zero-crossing wavelength point of QUI). Calibration graphs were constructed over the concentration range of 4.0 to 24.0 μ/mL for QUI and 2.5 to 15.0 μg/mL for HYD. Detection and quantitation limits were 0.85 and 2.5 μ

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Rohilla, Rajni, and Usha Gupta. "Simultaneous Determination of Cobalt (II) and Nickel (II) By First Order Derivative Spectrophotometry in Micellar Media." E-Journal of Chemistry 9, no. 3 (2012): 1357–63. http://dx.doi.org/10.1155/2012/739891.

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A first-derivative spectrophotometry method for the simultaneous determination of Co (II) and Ni (II) with Alizarin Red S in presence of Triton X-100 is described. Measurements were made at the zero-crossing wavelengths at 549.0 nm for Co (II) and 546.0 nm for Ni (II). The linearity is obtained in the range of 0.291- 4.676 μg/ml of Ni (II) and 0.293- 4.124 μg/ml of Co (II) in the presence of each other by using first derivative spectrophotometric method. The possible interfering effects of various ions were studied. The validity of the method was examined by using synthetic mixtures of Co (II)

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Mohammad, Muharram Y., Mohammad S. Abdullah, and Sangar S. Sabir. "Simultaneous Determination of Atenolol and Amlodipine Using Second Derivative Spectroscopy." Polytechnic Journal 9, no. 2 (2019): 25–29. http://dx.doi.org/10.25156/ptj.v9n2y2019.pp25-29.

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The present study describes employing second derivative spectrophotometry for simultaneous determination of atenolol and amlodipine in pure form and in commercial formulations. The method is simple, accurate, precise and economic. Zero crossing point technique was used for analysis of the drugs in the combined formulation. The method was found to be linear in the concentration range 5.0-50.0µg/ml of atenolol at 251nm and 5.0-45.0µg/ml of amlodipine at 264nm. The proposed method was successfully applied to determine atenolol and amlodipine in combined dosage as well as in a separate dosage. The

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Wrushali A. Panchale and Ravindra L. Bakal. "First-order derivative spectrophotometric estimation of gemifloxacin mesylate and ambroxol HCl in tablet dosage form." GSC Biological and Pharmaceutical Sciences 14, no. 2 (2021): 029–36. http://dx.doi.org/10.30574/gscbps.2021.14.2.0034.

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Aim of present work was to develop and validate a simple, precise and accurate uv-vis spectrophotometric method for the simultaneous estimation of gemifloxacin mesylate (GEMI) and ambroxol HCl (AMB) in their combined tablet dosage form. The method is based on first-order derivative spectroscopy. For determination of sampling wavelengths, each of GEMI and AMB were scanned in the wavelength range of 200–400 nm in the spectrum mode and sampling wavelengths were selected at 360 nm (zero crossing of GEMI) where AMB showed considerable absorbance and at 221.6 nm (zero crossing of AMB) where GEMI sho

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Wrushali, A. Panchale, and L. Bakal Ravindra. "First-order derivative spectrophotometric estimation of gemifloxacin mesylate and ambroxol HCl in tablet dosage form." GSC Biological and Pharmaceutical Sciences 14, no. 2 (2021): 029–36. https://doi.org/10.5281/zenodo.4605114.

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Aim of present work was to develop and validate a simple, precise and accurate uv-vis spectrophotometric method for the simultaneous estimation of gemifloxacin mesylate (GEMI) and ambroxol HCl (AMB) in their combined tablet dosage form. The method is based on first-order derivative spectroscopy. For determination of sampling wavelengths, each of GEMI and AMB were scanned in the wavelength range of 200–400 nm in the spectrum mode and sampling wavelengths were selected at 360 nm (zero crossing of GEMI) where AMB showed considerable absorbance and at 221.6 nm (zero crossing of AMB) where GE

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Deng, Ming, and Yuan Gao. "A high resistance grounding fault identification method for distribution network considering topological connection." Journal of Physics: Conference Series 2914, no. 1 (2024): 012027. https://doi.org/10.1088/1742-6596/2914/1/012027.

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Abstract Traditional high resistance grounding fault identification in distribution networks fails to meet load demands, demanding optimization for reliability and economics. A novel approach considers topological connections, applies the Hilbert-Huang transform for signal decomposition, refines components, and utilizes particle swarm optimization to enhance feature vectors. This defines an association matrix and leverages zero sequence current features, accurately pinpointing suspected high resistance ground faults through filtered second derivative concavity and zero crossing point analysis.

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Omer, Shilan A., and Nabil A. Fakhre. "Three Different Spectrophotometric Methods for Simultaneous Determination of Pyriproxyfen and Chlorothalonil Residues in Cucumber and Cabbage Samples." Journal of Spectroscopy 2019 (August 20, 2019): 1–11. http://dx.doi.org/10.1155/2019/8241625.

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In this study, three simple and accurate spectrophotometric methods for simultaneous determination of pyriproxyfen and chlorothalonil residues in cucumbers and cabbages grown in experimental greenhouse were studied. The first method was based on the zero-crossing technique measurement for first and second derivative spectrophotometry. The second method was based on the first derivative of the ratio spectra. However, the third method was based on mean centering of ratio spectra. These procedures lack any previous separation steps. The calibration curves for three spectrophotometric methods are

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Patel, Dhara, Jeel Dobariya, Prasanna Pradhan, Grishma Patel, and Dhananjay Meshram. "Development and Validation of UV Spectrophotometric methods for simultaneous estimation of Lobeglitazone Sulfate and Glimepiride in combined dosage form." Drug Analytical Research 8, no. 1 (2024): 62–69. http://dx.doi.org/10.22456/2527-2616.140749.

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Two UV spectrophotometric methods have been developed for accurately analyzing Lobeglitazone Sulfate and Glimepiride in combined dosage form, used in the treatment of type 2 diabetes mellitus. Method I, known as the simultaneous equation method (Vierodt’s Method), relies on measuring the absorption at 250 nm for Lobeglitazone Sulfate and 227 nm for Glimepiride, their respective λmax values. Method II involves the second-order derivative method, where the absorbance of Lobeglitazone Sulfate is measured at 297 nm (zero-crossing point of Glimepiride), and that of Glimepiride is measured at 259 nm

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Yang, Xu, Qi Long, Hao Li, et al. "Controlled Fault Current Interruption Scheme for Improved Fault Prediction Accuracy." Applied Sciences 15, no. 6 (2025): 3106. https://doi.org/10.3390/app15063106.

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To enhance the accuracy and efficiency of controlled fault current interruption (CFI) in short-circuit current processing within power systems, a half-cycle elimination prediction algorithm and a double-sampling CFI sequence method are proposed in this study. By analyzing the non-periodic and periodic components of short-circuit currents, the half-cycle elimination method and fast Fourier transform are utilized to compute these two components, respectively. The double-sampling CFI sequence approach is designed to fully utilize the response and waiting times of relay protection. Following the f

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Kurdaikar, S. S., A. Fernandes, S. V. Gandhi, P. Pattewar, and A. A. Mahajan. "Spectrophotometric Determination of Carbimazole and Its Major Impurity, Degradation Product and Metabolite: Methimazole -=SUP=-*-=/SUP=-." Оптика и спектроскопия 129, no. 7 (2021): 972. http://dx.doi.org/10.21883/os.2021.07.51090.1046-21.

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The present research work was carried out in order to develop simple, accurate and precise UV sprctrophotometric methods having comparable sensitivity as that of sophisticated chromatographic techniques. Two methods were developed namely first derivative spectrophotometry and ratio spectra derivative spectrophotometry for accurate determination of specified impurity methimazole (imp A) in presence of drug carbimazole. First derivative spectrophotometric method involves recording of zero order spectra of both the drugs carbimazole and methimazole and its mixture in the range of 200-400 nm and s

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Galera, M. Martínez, J. L. Martínez Vidal, A. Garrido Frenich, and P. Parrilla Vázquez. "Spectrophotometric Method To Determine Ternary Mixtures of Atrazine, Diuron, and Chlorpyrifos in Water and Soil by a Ratio Spectrum-Zero Crossing Method." Journal of AOAC INTERNATIONAL 78, no. 2 (1995): 423–30. http://dx.doi.org/10.1093/jaoac/78.2.423.

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Abstract A spectrophotometric method based on simultaneous use of first derivative of ratio spectra and measurement of zero-crossing wavelengths resolves ternary mixtures of atrazine, diuron, and chlorpyrifos. Calibration graphs were linear for atrazine between 1 and 15 μg/mL and for diuron and chlorpyrifos between 1 and 10 μg/mL. The pesticides in groundwater and soil were determined by the method, at part-per-billion levels, after solidphase extraction, with good results. Interferences caused by other pesticides were studied.

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Guzsvány, Valéria, Sanja Lazic, Natasa Vidakovic, and Zsigmond Papp. "Derivative spectrophotometric determination of acetamiprid in the presence of 6-chloronicotinic acid." Journal of the Serbian Chemical Society 77, no. 7 (2012): 911–17. http://dx.doi.org/10.2298/jsc110617015g.

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A simple first-order derivative spectrophotometric method was developed for the simultaneous determination of acetamiprid and 6-chloronicotinic acid (6-CNA) at pH 7.0. By using the zero-crossing approach, acetamiprid was determined at 269.0 nm and 6-CNA at 216.0 nm with the detection limits of 7.19x10-7 and 8.25x10-7 mol dm-3, respectively and relative standard deviations not exceeding 1.2% in the case of model systems.

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Coly, Atanasse, and Jean-Jacques Aaron. "Simultaneous Determination of Binary Mixtures of Sulfonylurea Herbicides in Water by First-Derivative Photochemically Induced Spectrofluorimetry." Journal of AOAC INTERNATIONAL 84, no. 6 (2001): 1745–50. http://dx.doi.org/10.1093/jaoac/84.6.1745.

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Abstract First-derivative photochemically induced spectrofluorimetry (PIF-1D) is applied to the simultaneous determination of binary mixtures of 4 sulfonylurea herbicides in aqueous micellar samples. Synthetic binary mixtures of sulfometuronmethyl with chlorsulfuron, metsulfuron-methyl, and 3-rimsulfuron, respectively, are well resolved by using the zero-crossing point procedure. PIF-1D allows the determination of binary mixtures of these herbicides with linear dynamic ranges over about 2 orders of magnitude, limits of detection between 0.5 and 52 ng/mL, and relative standard deviations within

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