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At least 469 records · Page 26Linked to original sources
PubMed1992

[Quantitative analysis of compound injection of aminopyrine by dual-wavelength linear regression spectrophotometry].

A dual-wavelength linear regression spectrophotometry has been introduced and evaluated. Depending on a group of standard mixture solutions the optimal wavelengths and calibration curve can be determined simultaneously by linear regression method. The deviation of absorption resulting from molecular interaction can be calibrated by this method and the results are more accurate. The validity of this method has been confirmed through its use in the analysis of compound injection of antipyrine with satisfactory recoveries. Results obtained by Kalman filtering (KF), partial least squares (PLS) and target factor analysis (TFA) are also given.

Aminopyrine↗
PubMedDate not supplied

[Prospects for promoting noninvasive spectrophotometry diagnosis in medicine].

Different aspects of optic invasion-free diagnostics in medicine are under discussion. The diagnostic possibilities of the method as well as the principles of its equipment-related and methodological realization are briefly analyzed. A conclusion is made on a unified optic invasion-free diagnostic technology in medicine and on its similarity to the general methods of laboratory spectrophotometry. Therefore, the designing of universal diagnostic complexes combining various diagnostic techniques on the bases of common diagnostic equipments is the most promising trend in developing the appropriate outfit for the diagnostic sphere.

Biopsy↗
PubMed2003

[Infrared spectrophotometry: a versatile analytical tool in hospital pharmacy].

Pharmacy services in healthcare facilities have increasing analytical needs, as frequently recalled by good practices guidelines (hospital pharmacy good practices, hospital pharmaceutical preparations good practices). Various analytical methods can be employed, from spot tests to the most recent chromatographic methods. The purpose of this paper is to demonstrate, with two concrete examples, the versatility and pertinence of one of these analytical methods: infrared spectrophotometry. We describe two current applications, used in a hospital pharmacy service: identification of pharmaceutical raw material and dose control of cytotoxic injectable preparations.

Antineoplastic Agents↗
PubMedDate not supplied

[UV spectrophotometry used for quantitative determination of oleanolic acid].

In order to adapt the UV spectrophotometry method to oleanolic acid dosing, absorption spectra within the range from 230 to 350 nm have been determined for both OA systems in glacial acetic acid (lambda max = 256 nm) and OA systems in ethyl alcohol (lambda max = 277 nm). The time stability of oleanolic acid in the presence of the two solvents has also been investigated in this study. Besides, the composition of etalon series and graphical representation of experimental results (n = 6) have been performed. Also, the calculation algorithm was given, the regression lines have been drawn and statistical parameters were calculated to establish the mathematical expression of OA concentration (mg%).

Algorithms↗
PubMed2004

Derivative-differential UV spectrophotometry and compensation technique for the simultaneous determination of zidovudine and lamivudine in human serum.

Three new simple, precise, rapid and selective determination methods are described for zidovudine (ZID) and lamivudine (LAM) in human serum and in pharmaceutical formulations. The first method, based on the compensation technique is presented for the derivative spectrophotometric determination of binary mixtures with overlapping spectra. Using ratios of the derivative maxima or the derivative minimum, the exact compensation of either component in the binary mixture and human serum can be achieved, followed by its determination. The second method, differential derivative spectrophotometry, comprised of measurement of the difference absorptivities derivatized in the first order (deltaD1) of a tablet extract in 0.1 N NaOH relative to that of an equimolar solution in methanol at wavelengths of 246 nm and 263 nm, respectively. Neither sample pretreatment nor separation were required. The third method is based on HPLC on a reversed-phase column using a mobile phase of 0.01M sodium dihydrogen phosphate : methanol : acetonitrile (4 : 2 : 3 v/v/v), with detection at 285 nm. Repeatability and reproducibility studies for each compound showed no significant differences at 95% confidence level. The proposed methods were used for the simultaneous determination of the drugs in human serum samples and binary mixtures with good recoveries.

Adult↗
PubMed2004

[Preparation of liposome podophyllotoxin chitosan film and determination the podophyllotoxin content in the film by ultraviolet spectrophotometry].

OBJECTIVE: To optimize the formula of liposome podophyllotoxin chitosan film and accurately determine the podophyllotoxin content in the film. METHODS: Liposome podophyllotoxin chitosan films were prepared according to different formula derived from the results of orthogonal design by selecting chitosan, acetic acid and gelatin as the 3 factors for preparation, each factor including 3 levels with liposome podophyllotoxin as the blank factor. Comprehensive evaluation of the formulas was performed on the basis of the conglutination and solubility of the prepared film to select the optimal formula. The content of podophyllotoxin was determined by ultraviolet spectrophotometry at 292 nm. RESULTS: The conglutination and solubility were optimal of the film prepared from 2% chitosan, 1% acetic acid, 2% gelatin and 2.8% liposome podophyllotoxin chitosan, showing good linearity within podophyllotoxin concentration range of 5-25 microg/ml (r=0.999 89) with an average recovery rate of 99.7% (n=5) and RSD of 1.11%. CONCLUSION: The film prepared according to the orthogonal design results conforms to the requirements in terms of conglutination and solubility, and the method we adopted is fast and accurate, yielding qualified film with censored podophyllotoxin content that distributes homogeneously.

Animals↗
PubMedDate not supplied

The measurement of salivary cadmium by electrothermal atomic absorption spectrophotometry and its use as a biological indicator of occupational exposure.

We have examined the potential use of salivary cadmium measurements for the biological monitoring of occupational cadmium exposure, paying particular attention to the contamination risks associated with such measurements. We have developed a method for the direct determination of cadmium in saliva by graphite furnace atomic absorption spectrophotometry, which minimizes the risk of contamination during sample preparation and analysis. The limit of detection is 0.6 nmoll-1, which is sufficiently sensitive to discriminate between unexposed and occupationally exposed individuals. The method has been employed to measure cadmium levels in saliva samples collected by two different methods from an unexposed population, a group of ex-workers previously exposed to cadmium (Group 1), and two groups of currently exposed workers (Groups 2 and 3). Salivary cadmium levels were significantly raised in both of the groups of currently exposed individuals (group 2 median (Md) = 17 nmoll-1, group 3 Md = 70 nmoll-1, p greater than 0.0001), and in past workers with previous long-term exposure (Group 1 Md = 2.5 nmoll-1, p greater than 0.001) when compared with an unexposed population. The results suggest that the measurement of salivary cadmium may reflect recent exposure to the metal. However, considerable care must be taken in collecting samples because a risk of contamination during sampling is apparent with procedures commonly used for saliva collection, and for this reason the applicability of such measurements for biological monitoring is limited.

Cadmium↗
PubMed1992

Near-infrared spectrophotometry: a new dimension in clinical chemistry.

The near-infrared (NIR) spectral region (700-2500 nm) is a fertile source of chemical information in the form of overtone and combination bands of the fundamental infrared absorptions and low-energy electronic transitions. This region was initially perceived as being too complex for interpretation and consequently was poorly utilized. Advances in chemometric techniques that can extract massive amounts of chemical information from the highly overlapped, complex spectra have led to extensive use of NIR spectrophotometry (NIRS) in the food, agriculture, pharmaceutical, chemical, and polymer industries. The application of NIRS in clinical laboratory measurements is still in its infancy. NIRS is a simple, quick, nondestructive technique capable of providing clinically relevant analyses of biological samples with precision and accuracy comparable with the method used to derive the NIRS models. Analyses can be performed with little or no sample preparation and no reagents. The success of NIRS in any particular case is determined by the complexity of the sample matrix, relative NIR absorptivities of the constituents, and the wavelengths and regression technique chosen. We describe the general approach to data acquisition, calibration, and analysis, using serum proteins, triglycerides, and glucose as examples.

Algorithms↗
PubMedDate not supplied

Application of derivative spectrophotometry to simultaneous determination of indomethacin and 5-methoxy-2-methyl-3-indoleacetic acid in metindol injections.

Derivative spectrophotometry was employed to develop a rapid and accurate method for simultaneous determination of indomethacin and 5-methoxy-2-methyl-3-indoleacetic acid as its possible impurity in Metindol injections. At the selected wavelengths, 233.04 and 284.65 nm, no interference between the components determined was observed. Under the established experimental conditions, recoveries of the particular components were from 96.14 to 98.17%. Linearity was maintained over a broad range of concentrations, from 11.88 x 10(-3) to 35.64 x 10(-3) mg/mL for indomethacin and 0.4 to 1.2 mg/mL for 5-methoxy-2-methyl-3-indoleacetic acid. The limit of detection was found to be 6.0 x 10(-3) mg/mL for indomethacin and 0.04 x 10(-3) mg/mL for 5-methoxy-2-methyl-3-indoleacetic acid. The limits of quantitation were found to be 10.0 x 10(-3) mg/mL and 0.20 x 10(-3) mg/mL, respectively.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Comparison of body composition assessment by hydrodensitometry, skinfolds, and multiple site near-infrared spectrophotometry.

Percent body fat (%BF) was assessed in 171 men with underwater weighing (UWW), seven-site skinfolds (7 SF), and near-infrared spectrophotometry (NIR). NIR was determined at eight sites, including biceps, triceps, axilla, chest, abdomen, suprailium, subscapula and thigh. Analysis of variance and Dunnett's post-hoc procedure revealed that NIR significantly (P less than 0.05) underpredicted %BF when using the biceps (12.9%), chest (11.3%), abdomen (10.2%), subscapula (11.3%) and thigh (9.9%) sites compared to the criterion %BF measured with UWW (13.4% +/- SD = 6.49). %BF with 7 SF was only 0.3% higher than %BF with UWW (r = 0.94, standard error of estimate = 2.9%). Correlation coefficients between SF thickness and NIR optical density readings at 940 nm (OD1) and 950 nm (OD2) wavelengths ranged from r = -0.30 (subscapula) to r = -0.67 (biceps) for OD1 and r = -0.39 (axilla) to r = -0.68 (biceps) for OD2. Multiple linear regression showed that the OD readings were not significant predictors of UWW %BF when using body mass, stature, activity level, and frame size as predictors, except for the OD2 reading at the biceps site. Stepwise regression revealed that NIR OD readings did not predict additional variance in %BF beyond mass, stature, activity level, frame size, or 7 SF. It was concluded that 7 SF are better predictors of %BF than NIR, and that NIR at multiple sites is inconsistent in assessing body composition.

Adipose Tissue↗
PubMed1997

[Determination of alkylmercuric compounds in human body fluids by gas chromatography--atomic absorption spectrophotometry].

In order to detect trace of alkylmercuric compounds in human body fluids, a highly sensitive, selective and rapid method, based on the coupling of gas chromatography with atomic absorption spectrophotometry, has been developed. The transfer-tube was made up of Teflon, with stainless steel tubes in the two sides. The atomization of alkylmercuric compounds was performed in quartz tube. The quantitative determination of alkylmercuric compounds in urine and blood samples collected from the workers exposing to metallic mercury, has been extensively carried out in this work. The optimal Westoo program was used to enrich methylmercuric chloride in samples, Extracts of methylmercuric chloride in benzene were determined by GC-AAS, with a total recovery of more than 90%. Dimethylmercury in samples was extracted once by xylene. Then the extracts were determined, with a total recovery of 65%-70%. The detectable limit for mercury was 0.01ng. The methylation of mercury was confirmed in our experiment. This method can be used for the determination of other metallic compounds.

Alkylmercury Compounds↗
PubMed2004

[Determination of trace germanium in coal by spectrophotometry with 2,4-dichlorophenylfluorone].

A method for the determination of germanium in coal samples by spectrophotometry has been developed. The color reaction of germanium with 2,4-dichlorophenylfluorone (2,4-DCIPF) in the presence of cetyltrimethylammonium bromide (CTMAB) has been studied. The results show that Ge(IV) reacts on 2,4-DCIPF and CTMAB to form a multicomponent complex in a 1.8-2.5 mol x L(-1) H2SO4 medium. The complex has the maximum absorption wavelength at 516 nm and its apparent molar absorptivity epsilon is 1.38 x 10(5) L x mol(-1) x cm(-1). Beer's law is obeyed in the range of 0-12.5 microg x (25 mL)(-1) for Ge(IV). The recovery of standard addition is 103%-106% and the relative standard deviation (RSD) is 1.1%-1.7%. This method has been applied to the determination of Ge(IV) in coal samples with satisfactory results.

4-Aminopyridine↗
PubMed2004

[Spectrophotometry determination of trace selenium(IV) in Chinese herbal medicine by catalytic kinetics. I. RDB and potassium bromate].

Trace Se(IV) can catalyze the discolouring oxidizing reaction of RDB with potassium bromate in nitric acid medium, and the conditions of kinetics has been studied in detail. A new method of kinetics spectrophotometry for determination of trace (IV) is established. The sensitivity of the method is 0.905 microg x L(-1). The range of measurement is 0-9.6 microg x L(-1). The method has been used for determining trace Se(IV) in Chinese herbal medicine with satisfactory results.

Bromates↗
PubMed2004

[Flame atomic absorption spectrophotometry for measurement of iron, manganese and zinc contents of wheat seeds].

The iron, manganese and zinc trace element contents of six different kinds of winter wheat seeds were studied by flame atomic absorption spectrophotometry. As a result, the rates of recovery of iron, manganese and zinc are 103.09%, 102.90% and 101.19%, respectively, and the relative standard deviations (RSDs) of Fe, Mn and Zn are smaller than 3.94%, 1.67% and 2.69%, respectively. Taking GBW08503 wheat flour as standard sample and carrying out comparative determination, the successful results were achieved. This method is very simple, rapid and accurate.

Calcium↗
PubMed2004

[Principle of determining the composition of complexes with the ratio of double peak values at double wavelengths by UV spectrophotometry].

In this paper, a new method for determining composition ratio of complexes was studied with ratio of double peak values at double wavelengths by UV spectrophotometry. The ratio of the maximum peak value to the minimum peak value and the composition ratio of complexes are the same. The calculation formula for the composition of complexes is deduced in accordance with beer's law and the theory of dissociation equilibrium of complexes: N = (deltaA2epsilonlambda1(MR) - deltaA1epsilonlambda2(MR)/(deltaA2epsilonlambda1(R) - deltaA1epsilonlambda2(R). The calculated value and that obtained by traditional method are agreeable. The method is reliable, simple, visual and quick.

Algorithms↗
PubMed2004

[Simultaneous determination of four-components in mixed herbicides by modified target factor analysis-UV spectrophotometry].

In this paper, the modified target factor analysis-UV spectrophotometry method is established for simultaneous determination of paraquat CL, cyanzine, metolachlor and atrazine in mixed herbicides. The experimental results show that the recovery of each herbicide by MTFA is more accurate than by TFA. The recovery of paraquat CL ranges from 99.47% to 102.02%, of cyanzine 98.93%-102.75%, of metolachlor 98.13%-102.65% and of atrazine 97.42%-103.20%, with SD for the four components to be 1.16%, 1.84%, 1.84% and 2.55% respectively. All in all, the modified target factor analysis method can be used to determine accurately mixed herbicides which exhibits intrinsic interaction among components.

Acetamides↗
PubMed2004

[Determination of trace copper and zinc in hypertension complicated with hyperlipemia by atomic absorption spectrophotometry].

The serum levels of Zn, Cu, cholesterol (Ch) and triglyceride (TG) were determined in 44 patients with hypertension complicated with hyperlipemia, 42 patients with hypertension (HP) and 30 healthy controls by atomic absorption spectrophotometry and automatic biochemical analytical instrument of reagent kit. It was found that the contents of Zn, Ch, TG and Zn/Cu ratio in hypertension complicated with hyperlipemia were significantly higher than in HP and control, while Cu in hypertension complicated with hyperlipemia was significantly lower than in HP and control. The contents of Zn, Ch, TG and Zn/Cu ratio in hypertension were significantly increased. It is suggested that hypertension complicated with hyperlipemia is closely related with Zn and Cu.

Aged↗
PubMed1997

[Determinaion of artificial synthetic pigment in the drug by reflection spectrophotometry].

Solid phase spectrophotometry is a new, simple, fast and sensitive trace analytical method. In this report, it is presented a method that the polyamide was used for the absorbence and the reflectances absorbances were measured directly with remodelled the colorimetric cell. Not only the trace inorganic ion can be analysed by the solid phase method, but also the artificial synthetic pigment in the drug can be determined, the results are satisfied.

Coloring Agents↗