Molar Absorptivity Values for Aflatoxins and Justification for Their Use as Criteria of Purity of Analytical Standards

1970 ◽  
Vol 53 (1) ◽  
pp. 96-101 ◽  
Author(s):  
J V Rodricks ◽  
L Stoloff ◽  
W A Pons ◽  
J A Robertson ◽  
L A Goldblatt
Keyword(s):  
Thin Layer ◽  
Statistical Study ◽  
Molar Absorptivity ◽  
Confidence Limits ◽  
Components Of Variance ◽  
Significant Difference ◽  
Single Determination ◽  
Comparison Measurements ◽  
Analytical Standards

Abstract Measurements of molar absorptivities in methanol were carried out by two laboratories on samples of anatoxins Bi and Gi prepared and purified independently in four laboratories and on samples of aflatoxins B2 and G2 prepared and purified independently in three laboratories. Molar absorptivities of pure aflatoxins Bi, B2, G1, and G2 in benzene-acetonitrile (98 + 2) were determined at two laboratories. With the exception of aflatoxin G2, no significant difference between aflatoxin samples could be demonstrated. Molar absorptivity values and absorbance ratios for each aflatoxin, based on these data, are given. Statistical 95% confidence limits were established for a single determination of molar absorptivity. A statistical study was made of the components of variance which contribute to the accuracy of the determination of molar absorptivity. A comparison of the fluorescence intensities of spots of various aflatoxin preparations, developed on silica gel-coated thin layer plates, with the amount of aflatoxin in each spotting solution as determined by absorbance measurements, demonstrated the validity of using absorbance and fluorescence comparison measurements for aflatoxin quantitation.

VALIDATED RP-HPLC AND UV-SPECTROSCOPY METHODS FOR THE ESTIMATION OF DAPAGLIFLOZIN IN BULK AND IN TABLETS

INDIAN DRUGS ◽  
2017 ◽  
Vol 54 (03) ◽  
pp. 44-51
Author(s):  
B. Sabbagh ◽  
B. V. S. Lokesh ◽  
G. A. Akouwah ◽  
Keyword(s):  
Good Accuracy ◽  
Uv Spectroscopy ◽  
Linear Regression Analysis ◽  
Molar Absorptivity ◽  
Hplc Method ◽  
Rp Hplc ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
Uv Visible

Two methods were developed for the determination of dapagliflozin (DAPA) in pure form and in tablets. The procedure utilized was UV-Visible Spectroscopy and RP-HPLC with PDA detector to quantify DAPA in bulk and tablets. The sensitive linear range was identified for both methods within 0.5-5.0μg/mL. The linear regression analysis was identified for both methods with correlation coefficient(r)>0.99. The LOD and LOQ values were found to be 0.05 μg/mL and 0.5 μg/mL for the method by UV-Spectroscopy. The molar absorptivity (ε) was calculated as 1.27 X 105 L.mol-1cm-1. The RP-HPLC method produced LOD and LOQ values of 1.0 ng/mL and 0.5 μg/mL. Both methods were simple, precise, reproducible to quantify the amount of unknown in bulk as well as in tablets and estimated accurately within the range of 100.0±0.5%. Statistical analysis was performed on the data obtained. There was no significant difference between the developed and reported methods with p>0.05. Both methods can be applied for routine analysis of DAPA in bulk and tablets with good accuracy and precision.

scholarly journals Extractive spectrophotometric determination of Quetiapine fumarate in pharmaceuticals and human urine using calmagite as an ion-pair reagent

2011 ◽  
Vol 17 (3) ◽  
pp. 259-267 ◽  
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiahf ◽  
Basavaiah Vinay
Keyword(s):  
Human Urine ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Official Method ◽  
Quetiapine Fumarate ◽  
Relative Standard ◽  
Significant Difference ◽  
Comparison Of The Results

Quetiapine fumarate (QTF) is an antipsychotic drug belonging to the benzisoxazole derivatives indicated for the treatment of schizophrenia. A sensitive and selective method based on dichloromethane-extractable ion-pair of QTF with calmagite (CGT), which exhibited an absorption maximum at 490 nm, is described. At this wavelength, Beer?s law is obeyed over the concentration range of 3.0 - 30.0 ?g ml-1. The apparent molar absorptivity, limit of detection (LOD) and quantitation (LOQ) values are 1.32 ? 104 l mol-1 cm-1, 0.27 and 0.81 ?g ml-1 respectively. The reaction is extremely rapid at room temperature and the absorbance values remain unchanged upto 19 h. The precision results, expressed as intra-day and inter-day relative standard deviation values, are satisfactory (RSD ? 2.2%). The accuracy is satisfactory as well (RE ? 2.44%). The method was successfully applied to the determination of QTF in pharmaceuticals and spiked human urine with satisfactory results. No interference was observed from common pharmaceutical adjuvants in tablets. Statistical comparison of the results with official method showed an excellent agreement and indicated no significant difference in precision.

scholarly journals Indirect spectrophotometric determination of diltiazem hydrochloride in pure form and pharmaceutical formulations

2005 ◽  
Vol 3 (3) ◽  
pp. 520-536 ◽  
Author(s):  
Akram El-Didamony
Keyword(s):  
Reference Method ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Diltiazem Hydrochloride ◽  
Spectrophotometric Methods ◽  
Chromotrope 2R ◽  
Significant Difference ◽  
Comparison Of The Results

AbstractThree simple, accurate, and sensitive spectrophotometric methods (A, B and C) have been described for the indirect assay of diltiazem hydrochloride (DIL.HCl), either in pure form or in pharmaceutical formulations. The first method (A) is based on the oxidation of DIL.HCl by N-bromosuccinimide (NBS) and determination of unconsumed NBS by measuring the decrease in absorbance of amaranth dye (AM) at a suitable λmax=521 nm. Other methods (B) and (C) involve the addition of excess cerric ammonium sulfate (CAS) and subsequent determination of the unconsumed oxidant by a decrease in the red color of chromotrope 2R (C2R) at a suitable λmax=528 nm or a decrease in the orange-pink color of rhodamine 6G (Rh6G) at λmax=525 nm, respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 3.0–9.0, 3.5–7.0 and 3.5–6.3 μg ml−1 for methods A, B and C, respectively. The apparent molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated. The proposed methods have been applied successfully for the analysis of the drug in its pure form and its dosage form. No interference was observed from a common pharmaceutical adjuvant. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

scholarly journals Sensitive and selective spectrophotometric assay of doxycycline hyclate in pharmaceuticals using Folin-Ciocalteu reagent

2010 ◽  
Vol 60 (4) ◽  
pp. 445-454 ◽  
Author(s):  
Pavagada Ramesh ◽  
Kanakapura Basavaiah ◽  
Nagaraju Rajendraprasad
Keyword(s):  
Molar Absorptivity ◽  
Spectrophotometric Assay ◽  
Doxycycline Hyclate ◽  
Limit Of Quantification ◽  
Pharmaceutical Tablets ◽  
Bulk Powder ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Significant Difference

Sensitive and selective spectrophotometric assay of doxycycline hyclate in pharmaceuticals using Folin-Ciocalteu reagentA spectrophotometric method for the determination of doxycycline (DOX) is described. The method is based on the formation of blue colored chromogen due to reduction of tungstate and/or molybdate in Folin-Ciocalteu (F-C) reagent by DOX in alkaline medium. The colored species has an absorption maximum at 770 nm and the system obeys Beer's law over the concentration range 0.75-12.0 μg mL-1DOX. The apparent molar absorptivity is 2.78 × 104L mol-1cm-1. The limit of quantification and detection values are reported to be 0.20 and 0.08 μg mL-1, respectively. Over the linear range applicable, the accuracy and precision of the method were evaluated on intra-day and inter-day basis. The reported mean accuracy value was 101.0 ± 1.7 %, the relative error was ≤ 2.7 % and the relative standard deviation was ≤ 2.5 %. Application of the proposed method to bulk powder and commercial pharmaceutical tablets is also presented. No significant difference was obtained between the results of the proposed method and the official BP method. The procedure described in this paper is simple, rapid, accurate and precise.

scholarly journals Spectrophotmetric Determination of Cefadroxil in Bulk and Dosage Form Using Sodium Hydroxide

2011 ◽  
Vol 8 (3) ◽  
pp. 1314-1322 ◽  
Author(s):  
S. W. Shantier ◽  
E. A. Gadkariem ◽  
K. E. Ibrahim ◽  
H. A. El-Obeid
Keyword(s):  
Sodium Hydroxide ◽  
Dosage Form ◽  
Molar Absorptivity ◽  
Direct Reaction ◽  
Confidence Limits ◽  
Chromatography Method ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatography Method ◽  
Liquid Chromatographic

A simple spectrophotometric method was developed for the determination of cefadroxil in pure bulk and in capsules forms. The method is based on a direct reaction between cefadroxil and sodium hydroxide (1 N). A product with λmaxat 342 nm and molar absorptivity of 7.9x103L mol-1cm-1is formed after heating cefadroxil with sodium hydroxide (1 N) for 30 minutes. The absorbance-concentration plot was rectilinear over the range 5-25 μg/mL with correlation coefficient values not less than 0.999. The detection limit (LOD) and quantification limit (LOQ) were 0.693 μg/mL and 2.31 μg/mL. The method was validated using the BP liquid chromatographic method for cefadroxil assay. The results obtained by the developed method for the capsules dosage form were statistically compared with those of the BP liquid chromatography method and evaluated at 95% confidence limits.

Determination of the visible spectra of electrode reaction products in strongly absorbing media by diffusion-controlled chronoabsorptometry

1996 ◽  
Vol 74 (7) ◽  
pp. 1403-1408 ◽  
Author(s):  
David H. Jones ◽  
A. Scott Hinman
Keyword(s):  
Thin Layer ◽  
Electrode Reaction ◽  
Molar Absorptivity ◽  
Bulk Solution ◽  
Reaction Products ◽  
Optical Absorbance ◽  
Current Path ◽  
Diffusion Controlled ◽  
Visible Spectra

Chronoabsorptometry under diffusion-controlled conditions has been applied to determination of the difference in molar absorptivity between electrode reaction products and reactants. The technique allows complete determination of the ultraviolet–visible spectra of reaction products that are stable on the time scale of a few hundred milliseconds. The technique was implemented with a reflectance cell that employs quartz light pipes to minimize optical absorbance of the bulk solution without obstructing the current path between counter and working electrodes. The spectrum of one-electron oxidized chloro-(5,10,15,20-tetraphenylporphinato)Fe(III) is determined with the new technique and compared with that obtained by conventional thin-layer spectroelectrochemistry. Key words: spectroelectrochemistry, chronoabsorptometry, thin-layer spectroelectrochemistry.

scholarly journals Spectrophotometric Determination of Certain Antiepileptic's in Tablets Using Vanillin Reagent

2016 ◽  
Vol 11 (2) ◽  
pp. 3540-3551
Author(s):  
Taghreed A. Mohammed ◽  
Mona A. Mohamed
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Coupling Reaction ◽  
Molar Absorptivity ◽  
Limit Of Quantification ◽  
Drug Products ◽  
Significant Difference ◽  
Student’S T ◽  
Comparison Of The Results

A selective and new spectrophotometric method is described for determination of three antiepileptic drugs; namely lamotrigine (LAM), gabapentin (GAB), and oxcarbazepine (OXC) in drug substances and in drug products using vanillin reagent as the chromogenic agent. The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the yellow colored products were measured at 405, 396, and 400 nm respectively. Beer’s law was obeyed at (0.4 – 10), (0.1-10), and (0.5-11) μg/mL, and  the calculated molar absorptivity values are 2.52 x 104, 1.74 x 104, and 2.54 x 104 L/mol/cm for LAM, GAB, and OXC respectively. Sandell sensitivity, the limit of detection (LOD) and limit of quantification (LOQ) were calculated. No interference was observed from common additives found in drug products. The presented method was validated according to ICH guidelines. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level, and there was no significant difference between the reference and proposed method with regard to accuracy and precision. The method offers the advantages of rapidity, simplicity and sensitivity and low cost and can be easily applied to resource poor settings without the need for expensive instrumentation and reagents.

scholarly journals Development and application of spectrophotometric method for quantitative determination of Metronidazole in pure and tablet formulations

2016 ◽  
Vol 2 (1) ◽  
pp. 28 ◽  
Author(s):  
Zeeshan Masood ◽  
Muhammad Tayyab Ansari ◽  
Sharjeel Adnan ◽  
Muhammad Asad ◽  
Muhammad Farooq ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Spectrophotometric Method ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Nitrite Ion ◽  
Colored Complex ◽  
Accuracy And Precision ◽  
Significant Difference

A rapid, simple and sensitive spectrophotometric method has been developed for the determination of metronidazole in pharmaceutical pure and dosage forms. The method depends on alkaline hydrolysis of metronidazole releases the nitro group as nitrite ion and yielded nitrite ions can be used to give a colored complex that absorbs maximally at 505 nm. Beer’s law is obeyed in the concentration ranges 9-100 mg/ml with molar absorptivity of 1.14 ×103 L mole-1 cm-1. The proposed method is precise, accurate and specific for the quantitative determination of drug in bulk and dosage forms. The results of analysis of commercial formulations and the recovery study of metronidazole suggested that there is no interference from any excipients, which are present in pharmaceutical formulations of metronidazole. Statistical comparison of the results was performed with regard to accuracy and precision using student’s t-test and F-ratio at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.

scholarly journals Sensitive and Selective Spectrophotometric Determination of Gabapentin in Capsules Using Two Nitrophenols as Chromogenic Agents

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sameer A. M. Abdulrahman ◽  
Kanakapura Basavaiah
Keyword(s):  
Picric Acid ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Lewis Base ◽  
Pure Form ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Significant Difference

Two simple and selective spectrophotometric methods have been proposed for the determination of gabapentin (GBP) in pure form and in capsules. Both methods are based on the proton transfer from the Lewis acid such as 2,4,6-trinitrophenol (picric acid; PA) or 2,4-dinitrophenol (2,4-DNP) to the primary amino group of GBP which works as Lewis base and formation of yellow ion-pair complexes. The ion-pair complexes formed show absorption maximum at 415 and 420 nm for PA and 2,4-DNP, respectively. Under the optimized experimental conditions, Beer's law is obeyed over the concentration ranges of 1.25–15.0 and 2.0–18.0 μg mL−1GBP for PA and 2,4-DNP methods, respectively. The molar absorptivity, Sandell's sensitivity, detection and, quantification limits for both methods are also reported. The proposed methods were applied successfully to the determination of GBP in pure form and commercial capsules. Statistical comparison of the results was performed using Student'st-test and F-ratio at 95% confidence level, and there was no significant difference between the reference and proposed methods with regard to accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition technique.

scholarly journals Comparison of high-performance thin layer chromatography/UV-densitometry and UV-derivative spectrophotometry for the determination of trimetazidine in pharmaceutical formulations

2019 ◽  
Vol 69 (3) ◽  
pp. 413-422
Author(s):  
Marcin Gackowski ◽  
Marcin Koba ◽  
Katarzyna Mądra-Gackowska ◽  
Stefan Kruszewski
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Pharmaceutical Formulations ◽  
Linear Calibration ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
Trimetazidine Dihydrochloride ◽  
Layer Chromatography

Abstract New methods for assaying trimetazidine dihydrochloride on the basis of thin layer chromatography and spectrophotometry are proposed and compared in the paper. In HPTLC/UV-densitometry, separation is achieved by using a mobile phase composed of ammonia-methanol (30:70, V/V) on silica gel HPTLC plates F254. Quantification using a non-linear calibration curve is accomplished by densito-metric detection at 230 nm. Derivative spectrophotometric determination of trimetazidine dihydrochloride is carried out from the fourth derivative of the absorbance at 233 nm in peak-zero mode. Statistical comparison led to the conclusion that there is no significant difference between the two studied methods and, moreover, that they demonstrate satisfactory accuracy and precision for routine applications.

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