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A densitometric high-performance thin-layer chromatographic (HPTLC) method for analysis of hydroquinone has been developed and validated. Chromatography was performed on aluminum foilbacked silica gel 60 F254 plates with chloroform-methanol 85:15 (% v/v) as mobile phase. This system furnished a compact band for hydroquinone at R F 0.51. Hydroquinone was quantified densitometrically at 289 nm. The limits of detection (LOD) and quantification (LOQ) were 38.50 and 115.50 ng per band, respectively. High precision and accuracy were achieved. The method was used for both qualitative and quantitative analysis of hydroquinone in commercial formulations. Because the method can effectively separate the hydroquinone in the presence of its degradation products, it can be used as a stability-indicating method.

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An ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry UPLC-QTOF-MS method has been developed for qualitative and quantitative analysis major compounds in Saussurea eopygmaea Hand-Mazz, which has long been used as a traditional Tibetan medicine. This method was validated to be sensitive, precise, and accurate with the limits of detection of compounds 2,3,4,6, and 7 with 0.67–1.90 μg mL−1, the overall intra-day and inter-day variations less than 8.45%, and the overall recovery over 93.8%, respectively. The correlation coefficients (R 2) of the calibration curves were higher than 0.998. In addition, by comparison MS and MS/MS spectra with those of authentic compounds and literatures, a total of 14 main peaks were identified within 6 min. These results demonstrate that this approach has the potential for quality control of S. eopygmaea and other Tibetan herbal medicines.

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High-performance thin-layer chromatographic (HPTLC) densitometric method for analysis of arbutin in commercial whitening creams was developed and validated. Aluminum-backed silica gel 60 F254 plates were used as stationary phase while methanol-chloroform-acetic acid 3.5:6:0.5 (%, v/v/v) mixture was used as mobile phase. Under these chromatographic conditions, arbutin was well separated from other ingredients. This system was found to give a well defined, sharp, and compact spot of arbutin at retention factor (R F) value of 0.40 ± 0.02. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 42.25 and 112.45 ng per spot respectively. The proposed method with high degree of precision and accuracy was employed for the analysis of arbutin both qualitatively and quantitatively in commercial whitening creams. Due to the efficiency of the method in separating arbutin from other ingredients including its degradation products, it can be applied as a stability-indicating method.

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This paper presents a new method for identification and quantitative analysis of six azole antifungal drugs — bifonazole, clotrimazole, econazole, fluconazole, ketoconazole, and miconazole — by capillary gas chromatography (CGC) combined with flame ionization detection (FID). The chromatographic separation conditions were established and the method was validated for precision (RSD = 1.49–3.55%), recovery (98.6–101.2%), and linearity within the range under investigation (∼1.0–33.3 ng). The results obtained show the newly developed procedure is suitable for qualitative and quantitative pharmaceutical analysis of the six azoles.

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The aim of this study was to determine the concentration of trace elements present in Sarkam ore by the standard addition method. The elements determined were Ca, Ti, Fe, Sr, Ba. The equipment used for this study was a Si(Li)-detector, a multichannel analyzer and 55Fe and 241Am radioisotope sources. The physical basis of the analytical method used, the procedure of sample preparation and the results are presented.

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This paper reports on the qualitative and quantitative analyses of light hydrocarbons produced by radiation degradation of N,N-diethylhydroxylamine. The results show that when the absorbed doses are between 10 and 1000 kGy, the main light hydrocarbons are methane, ethane, ethene, propane and n-butane. Their volume fractions are increased with the increase of the dose. The volume fraction of ethene is also increased at low doses with the increase of the dose, but it is decreased with the increase of dose at high doses.

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Conditions have been established for determination of diosmin in pharmaceutical formulations, for example ‘Diosminin’, by TLC with densitometric detection. Chromatographic separation on silica gel was performed with chloroform-methanol-water, 23 + 12 + 2 ( v/v ), as mobile phase and the spots were analyzed by densitometry at λ = 344 nm. Under the experimental conditions established repeatable and accurate results were obtained. The method is characterized by high sensitivity — the limit of detection was 20 ng — and satisfactory recovery — from 99.8 to 103.0%. Response was linearly dependent on concentration in the range 5 to 50 μg mL −1 .

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Energy-dispersive X-ray fluorescence spectrometry was applied for the analysis of historical silver coins to determine the elemental composition in a fast and non-destructive way. Ag, Cu and trace elements (V, Cr, Mn, Fe, Co, Ni, Hg, Pd, Zr, Mo, Rh, Ru) were determined in coins of King Mathias (Hungary, 1458–1490). A new data evaluation technique was used to avoid the problems arising from the different sizes, surfaces and geometries. The appropriateness of this method was confirmed by analysing certified silver/copper standard alloys.

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An accurate and rapid liquid chromatography–electrospray ionizaion– tandem mass spectrometry (LC—ESI—MS/MS) analytical method was developed and validated for the simultaneous determination of antcins A, B, C, H, and K, dehydroeburicoic acid, and 4,7-dimethoxy-5-methyl-1,3-benzodioxole in the extract and capsule of Antrodia cinnamomea (AC) fruiting body. These seven signature compounds were ionized using an electrospray ion source and analyzed by a triple-quadrupole mass analyzer under a multiple reaction monitoring (MRM) mode. The MRM transitions of m/z 453/409 (antcin A), m/z 467/408 (antcin B), m/z 469/425 (antcin C), m/z 485/413 (antcin H), m/z 487/407 (antcin K), m/z 467/337 (dehydroeburicoic acid), and m/z 197/139 (4,7-dimethoxy-5-methyl-1,3-benzodioxole) were used to quantify these seven components, respectively. Their calibration curves presented good linear regressions (R 2 > 0.997) within the tested concentration range. The intra- and inter-day precisions were less than 1.97% and 2.53%, respectively. The overall recovery was in the range of 87.55%–95.41%. This validated high-performance liquid chromatography (HPLC)—MS/MS method offers promising applications for the accurate and rapid quantification of signature compounds in the fruiting body and its commercial products.

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