Ultraviolet and light absorption spectrometry

Howell, James A. S.; Hargis, L. G.

doi:10.1021/ac00163a010

Cited by 17 publications

(6 citation statements)

References 664 publications

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“…5 Since derivative techniques have been widely applied: further development [6][7][8] and reviews were reported. [9][10][11][12][13][14][15][16][17] The main targets of reviews 17 were basic characteristics of DS and a few analytical applications of DS were given (The number of bibliographic references was 93).…”

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confidence: 99%

Recent Developments of Derivative Spectrophotometry and Their Analytical Applications

El‐Sayed

El-Salem

2005

ANAL. SCI.

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The zero-crossing derivative spectra method is the most common procedure for the simultaneous determination of binary mixtures of their overlapping spectra. As an example, the derivative spectra of binary mixtures of phospho-and silicomolybdenum blue are illustrated in Fig. 1. 23 By measuring the derivative values (heights h1 in Fig. 1) for mixtures of phosphate and silicate at 806 nm (zero-crossing wavelength of silicomolybdate complex), one can avoid the interference by silicate and the phosphate concentration can be determined. By measuring the derivative values (heights h2 in Fig. 1 Moreover, one disadvantage of the zero-crossing method is the necessity of selecting critical wavelengths for the measurements. This selection causes considerable loss of sensitivity and precision in case of binary mixtures. The so-called "ratio spectra derivative" permits the use of the wavelengths corresponding to maximum or minimum and also the use of the distance between consecutive maximum and minimum, thus avoiding these problems. 24 Salinas et al. 25 developed a derivative quotient spectra method with a standard divisor when the spectra of the components are overlapped. The method was based on dividing the spectrum for a mixture into the standard spectra for each of the analyses and driving the quotient to obtain a spectrum that is independent of the analyte concentration used as a divisor. The use of standardized spectra as divisors minimizes experimental errors and background noise. 26 An accurate choice of standard divisors and working wavelengths is fundamental for several reasons. 25,27,28 Easy measurements on separate peaks, higher values of the analytical signals and no need to work only at zero-crossing points (sometimes co-existing compounds have no maximum or minimum at these wavelengths) are advantages for ratio spectra derivative spectrophotometry in comparison with the zerocrossing derivative spectrophotometry. Also, the presence of a lot of maxima and minima in ratio spectra derivative data was another advantage, since these wavelengths give an opportunity for the determination of these compounds in the presence of other active compounds and excipients that possibly interfered with the assay. 29 2·1 Resolution of binary and ternary mixtures by applyingderivative ratio spectra (derivative quotient spectra) The absorption spectrum of a mixture of three compounds; A, B and C is determined by this equation:AM,λ i = εA,λ i CA + εB,λ i CB + εC,λ i CC (path-length is 1 cm)where, AM,λ i is the absorbance value of the mixture at wavelength λi, εA,λ i , εB,λ i and εC,λ i are the molar absorptivities of A, B and C at λi, CA, CP and CC are the molar concentrations of A, B and C, respectively. When we divide this spectrum by the spectrum of a standard solution of one of the components (e.g., A of concentration CA). That is bywe obtainThe first derivative of this spectrum ratio givesIf CC = 0, we have the binary mixture of A and B, and the spectrum in this case is:In Eq. (5) we can see that the derivative ratio spectrum of...

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Recent Developments of Derivative Spectrophotometry and Their Analytical Applications

El‐Sayed

El-Salem

2005

ANAL. SCI.

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“…7 illustrate that the combining ratio of NDP to the reagent γ-resorsolic acid is 1:1. The evident stability constant (Ks) [33] of the resulting azo dye was also calculated and found to be 6.7892x10 6 L/mol. This indicates that the azo-dye product has good stability.…”

Section: Nature Of the Resulting Azo Dyementioning

confidence: 99%

Improved Spectrophotometric Estimation of Nimodipine in the Pharmaceutical Formulation and Biological Fluids

Ahmed,

Mohammed

2023

PJAEC

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Nimodipine (NDP) belongs to the class of pharmacological agents known as calcium channel blockers. It is used to treat symptoms resulting from a ruptured blood vessel in the brain (hemorrhage). NDP increases blood flow to injured brain tissues. For its clinical importance, a sensitive, accurate and simple spectrophotometric approach for the evaluation of NDP in bulk, tablet and biological fluids has been developed. The procedure involves the reaction of the reduced NDP with equimolar nitrous acid then followed by coupling with the available γ-resorsolic acid reagent in a basic solution to give a colored azo dye. The resulting azo dye is soluble in water and shows a maximum absorption peak at 436 nm. All the variables which affect the conditions such as the influence of acid, γ-resorsolic acid and alkali concentrations, reaction time and Beer׳s law limits were studied carefully and adjusted. The optimal conditions showed the color of azo-dye was stable for more than 1 h. The method was found linear in the range from 1.0 to 40 μg/mL with a good value of determination coefficient (R2= 0.9988). The molar absorptivity was calculated and set up to be 1.8495x104 L/mol.cm. The detection limits and quantitation limits were also estimated and found to be 0.0059 and 0.0195 μg/mL, correspondingly. The approach was established by estimating NDP in pharmaceutical tablets and biological fluids. The precision (RSD) was calculated to be better than 0.324%, whereas the values of recovery percent and relative errors were in the range of 97.95% to 99.08 % and -3.78% to 2.22%, respectively, without interfering from any common excipients present in the samples. The nature of the yellow dye has been studied between diazotized NDP and γ-resorsolic acid reagent and was equal to 1:1.

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“…At this point the reading was recorded and DO was calculated as the burette reading of sodium-thiosulphate used in the whole titration process. Free carbon dioxide (CO2) was measured by titrimetric method using in N/44 NaOH and phenolphthalein indicator (Hargis, 1988). First, 100 ml of sample water is taken to a conical flask and added 10 drops of phenolphthalein indicator to it.…”

Section: Methodsmentioning

confidence: 99%

Limnological survey of dhaka-narayanganj-demra (dnd) dam area wetlands

Habib

Sarker

Uddin

et al. 2020

Bangladesh J. Zool.

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Present investigation was conducted to assess the physicochemical characteristics of water and its suitability for fish production at Dhaka-Narayanganj-Demra (DND) dam wetlands. Data were collected at eight points of the study area between March 2014and February 2015on temperature, transparency, pH, dissolved oxygen (DO) and free carbon dioxide (CO2) in the water. The average maximum water temperature, transparency, pH, DO, free CO2, hardness were recorded as34.6±0.4°C, 40.3±0.8cm, 7.9±0.06, 7.6±0.4 mgL-1,85.6±6.6 mgL-1 and 491.2±76mgL-1while minimum average were found as26.3±1.0°C,7.1±0.2 cm, 7.4±0.05, 5.9±0.3 mgL-1, 11.9±0.8 mgL-1 and 87.6±11.3 mgL-1respectively.All the water parameters were found in favourable condition for optimum freshwater fish production with some modification. This study can be the baseline data toward fresh fish supply and production prospect in the Dhaka city at wetland of the DND canal area. Bangladesh J. Zool. 48(1): 93-103, 2020

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Ultraviolet and light absorption spectrometry

Cited by 17 publications

References 664 publications

Recent Developments of Derivative Spectrophotometry and Their Analytical Applications

Recent Developments of Derivative Spectrophotometry and Their Analytical Applications

Improved Spectrophotometric Estimation of Nimodipine in the Pharmaceutical Formulation and Biological Fluids

Limnological survey of dhaka-narayanganj-demra (dnd) dam area wetlands

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