Advantage of zero-crossing-point first-derivative spectrophotometry for the quantification of calcium oxalate crystalline phases by infrared spectrophotometry

2000 ◽  
Vol 298 (1-2) ◽  
pp. 1-11 ◽  
Author(s):  
Laurence Maurice-Estepa ◽  
Pierre Levillain ◽  
Bernard Lacour ◽  
Michel Daudon
Keyword(s):  
Calcium Oxalate ◽  
Derivative Spectrophotometry ◽  
Infrared Spectrophotometry ◽  
Crystalline Phases ◽  
Zero Crossing ◽  
First Derivative ◽  
First Derivative Spectrophotometry ◽  
Crossing Point

Determining methemoglobin in blood by zero-crossing-point first-derivative spectrophotometry.

1987 ◽  
Vol 33 (10) ◽  
pp. 1767-1770 ◽  
Author(s):  
A Taulier ◽  
P Levillain ◽  
A Lemonnier
Keyword(s):  
High Sensitivity ◽  
Derivative Spectrophotometry ◽  
Derivative Spectrum ◽  
Zero Crossing ◽  
Standard Curve ◽  
First Derivative ◽  
First Derivative Spectrophotometry ◽  
Assay Precision ◽  
Crossing Point ◽  
Exact Point

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% methemoglobin content. Correlation with results by the Evelyn and Malloy method was very good for high proportions of methemoglobin (greater than 10%), but the proposed technique was far better for low methemoglobin percentages because of its linearity, its high sensitivity, and its low detection limit.

scholarly journals SIMULTANEOUS ESTIMATION OF ASPIRIN AND OMEPRAZOLE IN LABORATORY SAMPLE BY DIFFERENT UV SPECTROPHOTOMETRIC TECHNIQUES

INDIAN DRUGS ◽  
2020 ◽  
Vol 57 (09) ◽  
pp. 75-81
Author(s):  
Rakesh M Wani ◽  
Arun M Kashid ◽  
Amita Ghatge ◽  
Sumita Sahoo
Keyword(s):  
Simultaneous Equation ◽  
Ratio Method ◽  
Simultaneous Estimation ◽  
Laboratory Sample ◽  
Zero Crossing ◽  
Spectrophotometric Methods ◽  
First Derivative ◽  
First Derivative Spectrophotometry ◽  
Curve Method ◽  
Crossing Point

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 isoabsorptive point and other being the λ max of one of the two components. From the overlay spectra of two drugs, it is evident that aspirin and omeprazole show an isoabsorptive point at 238.6 nm. In zero crossing first derivative spectrophotometry, aspirin showed zero crossing point at 301nm and omeprazole showed zero crossing point at 274nm. Linearity for aspirin was between 25- 125 μg/mL and omeprazole it was 3-15 μg/mL. These methods were successfully applied for estimation of aspirin and omeprazole in the laboratory sample.

scholarly journals HPLC, TLC, and First-Derivative Spectrophotometry Stability-Indicating Methods for the Determination of Tropisetron in the Presence of Its Acid Degradates

2010 ◽  
Vol 93 (4) ◽  
pp. 1180-1191 ◽  
Author(s):  
Laila S Abdel-Fattah ◽  
Zeinab A El-Sherif ◽  
Khadiga M Kilani ◽  
Dalia A El-Haddad
Keyword(s):  
Degradation Product ◽  
Mobile Phase ◽  
Degradation Products ◽  
Derivative Spectrophotometry ◽  
Pharmaceutical Dosage Form ◽  
Zero Crossing ◽  
Stability Indicating ◽  
First Derivative ◽  
First Derivative Spectrophotometry

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 + 0.2, v/v/v/v) mobile phase and UV detection at 285 nm. The TLC method was based on the separation of tropisetron and its acid-induced degradation products, followed by densitometric measurement of the intact spot at 285 nm. The separation was carried out on silica gel 60 F254 aluminum sheets using methanolglacial acetic acid (22 + 3, v/v) mobile phase. The 1D method was based on the measurement of first-derivative amplitudes of tropisetron in H2O at the zero-crossing point of its acid-induced degradation product at 271.9 nm. Linearity, accuracy, and precision were found to be acceptable over concentration ranges of 40240 g/mL, 110 g/spot, and 636 g/mL for the HPLC, TLC, and 1D methods, respectively. The suggested methods were successfully applied for the determination of the drug in bulk powder, laboratory-prepared mixtures, and a commercial sample.

scholarly journals Spectrophotometric Determination of Carbimazole and Its Major Impurity, Degradation Product and Metabolite: Methimazole -=SUP=-*-=/SUP=-

2021 ◽  
Vol 129 (7) ◽  
pp. 972
Author(s):  
S.S. Kurdaikar ◽  
A. Fernandes ◽  
S.V. Gandhi ◽  
P. Pattewar ◽  
A.A. Mahajan
Keyword(s):  
Accurate Determination ◽  
Research Work ◽  
Derivative Spectrophotometry ◽  
Chromatographic Technique ◽  
Zero Crossing ◽  
First Derivative ◽  
Derivative Spectra ◽  
Subsequent Conversion ◽  
First Derivative Spectrophotometry

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 subsequent conversion of these spectra into first derivative spectra. The drugs carbimazole and methimazole were determined by using zero crossing wavelengths of 227 and 260 nm respectively. In the second approach, ratio spectra were recorded for carbimazole and methimazole by selecting appropriate divisor concentration and converted into first derivative spectra. The determination of carbimazole and methimazole were carried out at wavelength 226.2 and 257 nm, respectively. Both the methods were validated as per ICH guideline. The drugs carbimazole and methimazole showed linear response with good correlation coefficient and exhibited specificity, accuracy and precision within acceptable range. The second method of ratio spectra derivative spectrophotometry was found more sensitive as compare to first derivative spectrophotometry in detecting level of impurity methimazole up to 0.5% as per official specification. Hence, these developed methods can be used as alternative to sophisticated chromatographic technique for determination of assay and related impurity in bulk drug and formulation. Keywords: carbimazole, methimazole, first derivative spectrophotometry, ratio spectra derivative spectrophotometry.

scholarly journals Simultaneous Determination of Cobalt (II) and Nickel (II) By First Order Derivative Spectrophotometry in Micellar Media

2012 ◽  
Vol 9 (3) ◽  
pp. 1357-1363 ◽  
Author(s):  
Rajni Rohilla ◽  
Usha Gupta
Keyword(s):  
Simultaneous Determination ◽  
Derivative Spectrophotometry ◽  
Micellar Media ◽  
Alizarin Red ◽  
Zero Crossing ◽  
First Order ◽  
First Derivative ◽  
First Derivative Spectrophotometry ◽  
Triton X

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) and Ni (II). The developed derivative procedure, using the zero crossing technique, has been successfully applied for the simultaneous analysis of Co (II) and Ni (II) in spiked water samples.

scholarly journals Liquid Chromatographic and Spectrophotometric Determination of Diflucortolone Valerate and Isoconazole Nitrate in Creams

2011 ◽  
Vol 94 (1) ◽  
pp. 128-135 ◽  
Author(s):  
Elif Karacan ◽  
Mehmet Gokhan Çaġlayan ◽  
İsmail Murat Palabiyik ◽  
Feyyaz Onur
Keyword(s):  
Principal Component Regression ◽  
Principal Component ◽  
Derivative Spectrophotometry ◽  
Data Matrix ◽  
Concentration Data ◽  
Spectrophotometric Methods ◽  
First Derivative ◽  
First Derivative Spectrophotometry ◽  
Liquid Chromatographic

Abstract A new RP-LC method and two new spectrophotometric methods, principal component regression (PCR) and first derivative spectrophotometry, are proposed for simultaneous determination of diflucortolone valerate (DIF) and isoconazole nitrate (ISO) in cream formulations. An isocratic system consisting of an ACE® C18 column and a mobile phase composed of methanol–water (95+5, v/v) was used for the optimal chromatographic separation. In PCR, the concentration data matrix was prepared by using synthetic mixtures containing these drugs in methanol–water (3+1, v/v). The absorbance data matrix corresponding to the concentration data matrix was obtained by measuring the absorbances at 29 wavelengths in the range of 242–298 nm for DIF and ISO in the zero-order spectra of their combinations. In first derivative spectrophotometry, dA/dλ values were measured at 247.8 nm for DIF and at 240.2 nm for ISO in first derivative spectra of the solution of DIF and ISO in methanol–water (3+1, v/v). The linear ranges were 4.00–48.0 μg/mL for DIF and 50.0–400 μg/mL for ISO in the LC method, and 2.40–40.0 μg/mL for DIF and 60.0–260 μg/mL for ISO in the PCR and first derivative spectrophotometric methods. These methods were validated by analyzing synthetic mixtures. These three methods were successfully applied to two pharmaceutical cream preparations.

scholarly journals Spectrophotometric Stability-Indicating Methods for the Determination of Leflunomide in the Presence of Its Degradates

2006 ◽  
Vol 89 (6) ◽  
pp. 1524-1531 ◽  
Author(s):  
Samah S Abbas ◽  
Lories I Bebawy ◽  
Laila A Fattah ◽  
Heba H Refaat
Keyword(s):  
Dosage Forms ◽  
Derivative Spectrophotometry ◽  
Reaction Conditions ◽  
Pharmaceutical Dosage Forms ◽  
First Derivative ◽  
Beer's Law ◽  
First Derivative Spectrophotometry ◽  
Colored Product ◽  
Beer’S Law

Abstract Five simple and sensitive methods were developed for the determination of leflunomide (I) in the presence of its degradates 4-trifluoromethyl aniline (II) and 3-methyl-4-carboxy isoxazole (III). Method A was based on differential derivative spectrophotometry by measuring the △1D value at 279.5 nm. Beer's law was obeyed in the concentration range of 2.0020.00 μg/mL with mean percentage accuracy of 100.07 1.32. Method B depended on first-derivative spectrophotometry and measuring the amplitude at 253.4 nm. Beer's law was obeyed in the concentration range of 2.0016.00 μg/mL with mean percentage accuracy of 98.42 1.61. Method C was based on the reaction of degradate (II) with 2,6-dichloroquinone-4-chloroimide (Gibbs reagent). The colored product was measured at 469 nm. Method D depended on the reaction of degradate (II) with para-dimethyl aminocinnamaldehyde (p-DAC). The absorbance of the colored product was measured at 533.4 nm. Method E utilized 3-methyl-2-benzothiazolinone hydrazone in the presence of cerric ammonium sulfate with degradate (II). The green colored product was measured at 605.5 nm. The linearity range was 40.00-280.00, 2.40-24.00, and 30-250 μg/mL with mean percentage accuracy of 100.75 1.21, 100.13 1.45, and 99.74 1.39 for Methods CE, respectively. All variables were studied to optimize the reaction conditions. The proposed methods have been successfully applied to the analysis of leflunomide in pharmaceutical dosage forms and the results were statistically compared with that previously reported.

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