Derivative spectroscopy

In analytical chemistry derivative spectroscopy is frequently used if the 

In general mathematical diff ntiation is superior to the differentiation of the analogue signal, because in the latter case the original data are lost and not available for later ftirther manipulation. Furthermore differentiation happens with respect to time instead of wavelength in the case of used analogue signals. Time constants and any fluctuations of the electronic parts of the spectrometer influence the result. However, these aspects are discussed controversially in the literature [85,86]. 

Derivation reaction spectrum of the photoreaction tronr-stilbene to phenanthrene 

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DETERMINATION OF THE ACTIVE CONSTITOENTS IN A MEDICINAL PREPARATION OY DERIVATIVE SPECTROSCOPY 17.51... 

Determination of the active constituents in a medicinal preparation by derivative spectroscopy 717... 

D.T. Williams et al, Evaluation of Second Derivative Spectroscopy For Monitoring Toxic Air Pollutants , SAM TR-74-19, Proj AF-7164, Contract F 41609-73-C-0011 (1974)... 

Zhao, Q., Sannier, F., Garreau, I., Lecoeur, C., and Piot, J. M., Reversed-phase high-performance liquid chromatography coupled with second-order derivative spectroscopy for the quantitation of aromatic amino acids in peptides application to hemorphins, /. Chromatogr. A, 723, 35, 1996. 

The methylxanthines show useful strong ultraviolet (UV) absorption between 250 and 280 nm.11 The spectra for the methylxanthines are very similar and only when one uses techniques such as derivative spectroscopy can substantial differences be seen. In addition to the UV absorption, the methylxanthines also exhibit strong infrared (IR) spectra which can provide critical information about these compounds. 

The most basic method for the determination of the methylxanthines is ultraviolet (UV) spectroscopy. In fact, many of the HPLC detectors that will be mentioned use spectroscopic methods of detection. The sample must be totally dissolved and particle-free prior to final analysis. Samples containing more than one component can necessitate the use of extensive clean-up procedures, ajudicious choice of wavelength, the use of derivative spectroscopy, or some other mathematical manipulation to arrive at a final analytical measurement. A recent book by Wilson has a chapter on the analysis of foods using UV spectroscopy and can be used as a suitable reference for those interested in learning more about this topic.1... 

The extent of homogeneous mixing of pharmaceutical components such as active drug and excipients has been studied by near-IR spectroscopy. In an application note from NIRSystems, Inc. [47], principal component analysis and spectral matching techniques were used to develop a near-IR technique/algorithm for determination of an optimal mixture based upon spectral comparison with a standard mixture. One advantage of this technique is the use of second-derivative spectroscopy techniques to remove any slight baseline differences due to particle size variations. 

There are many ways to obtain information on the physico-chemical properties of materials. Figure 1.3 presents a scheme from which almost all techniques can be derived. Spectroscopies are based on some type of excitation, represented by the ingoing arrow in Fig. 1.3, to which the catalyst responds as symbolized by the outgoing arrow. For example, one can irradiate a catalyst with X-rays and study how the X-rays are diffracted (X-ray diffraction, XRD), or one can study the energy distribution of electrons that are emitted from the catalyst as a result of the photoe-... 

De Re Metallica (Agricola), 16 126, 595 Derivative fibers, 11 247 24 616 Derivative formation, from hydrogen peroxide, 14 67 Derivatives, reducing, 12 805 Derivative spectroscopy, 23 139, 144 Derivatization... 

Y. Ren, W. Li, Y. Guo, R. Ren, L. Zhang, D. Jin and C. Hui, Study on quality control of metronidazole powder pharmaceuticals using near infrared reflectance first-derivative spectroscopy and multivariate statistical classification technique, Jisuanji Yu Ymgyong Huaxue, 14, 105-109 (1997). 

D.G. (1986) Relationship among derivative spectroscopy, color, crystallite dimensions and A1 substitution of synthetic goethites and hematites. Clays Clay Min. 34 625-634 Kosowski, B.M. (1993) Nanometer sized iron oxide. Paper presented at Iron oxides in colorant and chemical application". Intertec Conferences. Washington, D.C. 

First-derivative spectrophotometry was used to identify chlorpromazine in the presence of other phenothiazines, while second derivative spectrophotometry enabled the direct determination of chlorpromazine in spiked blood samples [89], In addition, third derivative spectroscopy was used to determine chlorpromazine and its sulfoxide decomposition product in pharmaceutical dosage forms [90]. 

Hearn, M.T., M.I. AgnUar, T. Nguyen, and M. Fridman, High-performance liquid chromatography of amino acids, peptides and proteins. LXXXTV. Application of derivative spectroscopy to the study of column residency effects in the reversed-phase and size-exclusion liquid chromatographic separation of proteins. J Chromatogr, 1988. 435(2) 271-84. 

In many cases, higher bands or band extrema must be included in the analysis, i.e., one must consider in Eq. (55). This point has been made in the same papers by Grimmeiss et al. (1974) and Morgan (1975), especially if transitions to the lower band(s) are symmetry forbidden. It has also been emphasized for derivative spectroscopy by White et al. (1976). 

A survey of normal and derivative spectra of numerous vitamins, including vitamin Bg, has been reported. The second derivative spectra of these vitamins are especially suitable for their quantitative determinations (132). Quantitative determination by derivative spectroscopy is superior to direct spectrophotometric measurement in many problem situations. 

A. Bettero and P. Bollettin, Atropine sulfate determination by derivative spectroscopy HPLC, Ann. Chim., 75 351 (1985), Rome. 

First-derivative spectroscopy was applied to the analysis of mixture of spironolactone and frusemide in combined dosage forms [19], Calibration curves were linear up to 20 pg/mL. The same mixture has been analyzed by extraction with methanol, and subsequent measurement in either 0.1 N HC1 or in 0.1 N NaOH [20], The relative standard deviation was in the... 

Wahbi reported on the use of second-derivative spectroscopy for the determination of canrenone in spironolactone, and found that the method is stability-indicating for spironolactone [21]. First and second-derivative spectroscopy were also utilized for the simultaneous analysis of spironolactone in combination with either hydrochlorothiazide or frusemide [22], The drugs are extracted with ethanol and analyzed through the use of the zero-crossing method. Nowakowska [23] analyzed mixtures of spironolactone and hydrochlorothiazide in tablets by measuring the absorbance of all species at 239 nm, and that of hydrochlorothiazide at 318 nm. The recoveries for spironolactone were found to be 97.9 to 101.8%, with a coefficient of variation of less than 0.1%. 

Other spectrophotometric techniques have been reported for the analysis of spironolactone. Near infrared diffuse reflectance first-derivative spectroscopy was used for determination of spironolactone in pharmaceutical dosage forms [30]. Readings were taken at 15 nm intervals, and then 81 absorbance readings were imput into a computer for principal component analysis. 

A similar difference has been observed for Kp M values of the anticancer drags tamoxifen and 4-hydroxytamoxifen determined in mitochondria, sarcoplasmic reticulum, and in liposomes made from lipids extracted from the corresponding native membranes [85]. The largest Kp M was observed in mitochondria, followed by sarcoplasmic reticulum and liposomes. The authors introduced for these experiments derivative spectroscopy, a reliable and rapid procedure to estimate drag partitioning into biomembranes. The method used the shift in the absorption spectra of the drug when removed from the aqueous phase to a hydrophobic environment (see Section 3.10). 

Karstang, T.V. and Kvalheim, O., Multivariate prediction and background correction using local modeling and derivative spectroscopy, Anal. Chem., 63, 767-772, 1991. 

The second recent spectroscopic improvement is second and fourth derivative spectroscopies in the ultraviolet region of proteins. Derivative spectroscopy is a new tool for analyzing the effects of pressure on proteins. It permits one to enhance selectively spectral changes due to the UV absorbance of phenylalanine, tyrosine and tryptophan. The solvent polarity affects the amplitude, the position and the shape of the second and fourth derivative spectral bands. 

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