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PubMed1989

[A fast determination of serum bilirubin with the interference from hemolysis and turbidity by three wavelength spectrophotometry].

In determination of bilirubin in serum by means of color reaction when hemolysis and turbidity are present, the reliability of the measurement is decreased by the interference from hemoglobin and other turbidities. Direct measurement of bilirubin in serum by three wavelength spectrophotometry at 500 nm, 450 nm and 370 nm instead of by color reaction, provides a fast, semi-micro and accurate way without the use of any reagents. Besides the rise of the baseline by blood cells and turbidities can be corrected without the consideration of hemolysis. Under the given experimental condition, the mean recovery is 96.3 +/- 2.41% (n = 6), coefficient of variation (CV) is 4.0%.

Bilirubin↗
PubMed1989

Direct determination of lead in urine by flameless atomic absorption spectrophotometry with platform atomisation.

A direct method of urinary lead assay by flameless atomic absorption spectrophotometry is described for routine use in the clinical laboratory. It employs a simple sample pre-treatment procedure preceding automated analysis. Reproducibility, linearity and recovery were satisfactory without the need of standard addition. Mean and reference intervals of normal urine were similar to values reported in the literature.

Humans↗
PubMed1989

[Studies on multiwavelength absorbance ratio difference spectrophotometry and its application].

This paper provides a new method to determine mixed component system by multiwavelength absorbance ratio difference spectrophotometry and summarized the basic principle and experimental technique of this method. This method was applied to assay the contents of two kinds of mixed component system of diphenhydramine hydrochloride and ephedrine hydrochloride, amidopyrine and caffeine without separation. The mean recoveries with coefficient of variation (%) was 101.0% (1.0%) for ephedrine hydrochloride; 94.86% (0.56%) for diphenhydramine hydrochloride; 100.3% (0.70%) for amidopyrine and 100.1% (0.75%) for caffeine. The results obtained are satisfactory both in recovery and in precision. It is a simple and rapid method to determine mixed component system.

Aminopyrine↗
PubMed1989

[Simultaneous qualitative and quantitative analysis of mixtures by multivariate spectrophotometry].

By the use of stepwise regression method in conjunction with the theory of figures of merit for the multicomponent spectrophotometry, mixtures with known scope of possibly present species can be simultaneously analyzed qualitatively and quantitatively. There is no need for the analysis to acquire the spectral data matrix from a series of mixture samples with varied concentration as for the case of target transformation factor analysis. Analytical results can be obtained from the spectral data vector of just one assayed sample. The method has been testified by analyzing synthetic mixtures and pharmaceutical preparations with satisfactory results.

Amino Acids↗
PubMed1989

[Contribution of spectrophotometry of the cerebrospinal fluid in the rational treatment of subarachnoid hemorrhage].

In connection with antifibrinolytic therapy of subarachnoid hemorrhage which reduces, especially at the acute stage, the risk of repeated bleeding, more frequent incidence of other serious complications was observed, i.e. late ischemic neurological deficiency. As this complication is prognostically serious and therapeutical effects are not satisfactory its prevention is necessary, which includes administration of antifibrinolytic drugs for a limited time period. Such period may be determined by means of dynamic study of hemoglobin degradation products in the liquor using liquor spectrophotometry.

Adult↗
PubMedDate not supplied

Direct analysis of platinum in plasma and urine by electrothermal atomic absorption spectrophotometry.

An improved technique is described for analysis of platinum (Pt) concentrations in plasma and urine by electrothermal atomic absorption spectrophotometry (EAAS). The method is intended for use in therapeutic monitoring of cancer patients treated with platinum-containing antitumor drugs. Samples (0.1 ml) of plasma, urine, or Pt standards are diluted to two ml with a matrix solution that contains diammonium edetate, ammonium dihydrogen phosphate, ammonium hydroxide, and octoxynol detergent. Concentrations of Pt in the diluted samples are determined directly by EAAS analysis with Zeeman background correction. Standard additions are unnecessary; Pt concentrations are read from a calibration chart of peak heights, which is linear up to 1.6 mg per liter. The detection limit is 0.02 mg of Pt per liter. Day-to-day precision (coefficient of variation, based on 21 consecutive runs) ranges from 4.2 to 11.7 percent, depending upon the Pt concentration in the plasma and urine specimens. Recovery of Pt added to plasma and urine specimens averages 103 +/- 8 and 99 +/- 6 percent, respectively. Concentrations of Pt are stable in plasma and urine specimens stored at 4 degrees C or -20 degrees C for four weeks. Analyses of Pt concentrations in serial plasma and urine specimens from cancer patients receiving cisplatin chemotherapy demonstrate the clinical utility of the technique.

Cisplatin↗
PubMedDate not supplied

Determination of polysorbates in foods by colorimetry with confirmation by infrared spectrophotometry, thin-layer chromatography, and gas chromatography.

A method is presented for the detection of polysorbates (PSs) in 8 kinds of processed foods by colorimetric and thin-layer chromatographic (TLC) techniques. The PSs are extracted from processed foods with a mixture of methylene chloride and ethanol by using an Extrelut column. The extract is further purified by using a silica gel column. The PS extract is complexed with cobalt-thiocyanate (Cothiocyanate) reagent and is determined spectrophotometrically at 620 nm. The recoveries and coefficients of variation for 8 kinds of processed foods fortified with 0.1% PS 80 were 67.9-94.6% and 4.0-11.3%, respectively. The detection limit of TLC corresponded to 50 mg PS 80/kg. PS identity was confirmed by infrared spectrophotometry of PS extract, and gas chromatography of fatty acids and thin layer chromatography of POE-sorbitan residues after saponification.

Chromatography, Gas↗
PubMed1989

[Direct spectrophotometric determination of urinary uroporphyrin and coproporphyrin using zerocrossing second derivative spectrophotometry].

The use of zero-crossing second-derivative spectrophotometry allows simultaneous determination of uroporphyrin and coproporphyrin directly in urines. Linearity and repeatability are excellent. Detection limit is about 8 nmol/l. Specificity is excellent too, except in unusual porphyrias where porphyrins with 5, 6 or 7 carboxylic groups are encountered. In such a case, this method allows the detection of increased porphyrins contents. The main advantage of this technique is its simplicity: it needs just to acidify urines and to plot a spectrum from 380 to 440 nm to determine the uroporphyrin and coproporphyrin concentrations. So it may be a very useful technic for clinical biochemistry laboratories in charge of monitoring patients suffering from porphyria.

Coproporphyrins↗
PubMed1988

[Glaphenine biliary lithiasis. Identification by infrared spectrophotometry].

The authors report the case of a woman, presenting with choledocholithiasis essentially composed of glafenic acid. Identification of the drug and its metabolites was demonstrated using infrared spectrophotometry and thin layer chromatography. To our knowledge, this is the first publication of drug choledocholithiasis.

Aged↗
PubMed1985

A noninvasive method for monitoring the effects of increased intracranial pressure with near infrared spectrophotometry.

Two experiments were conducted to assess the feasibility of near infrared spectrophotometry (niroscopy) to monitor directly the effects of increased intracranial pressure on brain metabolism. ICP was increased in cats by subarachnoid infusion of a "mock" CSF solution. Cytochrome a,a3 redox state, oxyhemoglobin, deoxyhemoglobin and cerebral blood flow were noninvasively and continuously monitored by niroscopy. The results of both experiments indicated that changes in ICP correlated with a reduction in cytochrome a,a3 redox state (p less than 0.01), a decrease in the quantity of oxyhemoglobin and cerebral flow (p less than 0.01) and an increase in deoxyhemoglobin. The study results suggest that niroscopy has the potential for providing noninvasive and continuous data for assessing brain metabolic activity. The correlations obtained with simultaneous measurements of intracranial pressure make this an attractive method for application to those at risk for increased intracranial pressure.

Animals↗
PubMedDate not supplied

Determination of gold in animal tissue by graphite furnace atomic absorption spectrophotometry.

Historically, compounds that contain gold have been used to treat conditions such as rheumatoid arthritis in humans. However, understanding of the metabolic fate of gold in biological tissues has been limited by lack of sensitive quantitative methods of analysis. We addressed this problem by developing a graphite furnace atomic absorption (GFAA) spectrophotometric method to measure trace amounts of gold. This method was validated on small samples of beef liver, kidney, and bone. The samples were digested in micro-Kjeldahl flasks with a mixture of sulfuric, perchloric, and nitric acids; the residue was treated with aqua regia and extracted into methylisobutyl ketone (MIBK); levels of gold were then measured by GFAA. All the reagents were of an ultra-pure grade and were monitored for gold content. We established that the linear range of quantitation was from 1 to 2500 ppb. Multiple extractions with MIBK were not necessary to recover all the gold, and, in most cases, use of ultra-pure acids was not necessary. A scan of the extracts by inductively coupled argon plasma atomic emission spectrophotometry revealed no appreciable concentration of elements that would be most likely to interfere with the determination of gold. Average recoveries of gold ranged from 102 to 111%, and the overall coefficient of variation was 5.5%.

Animals↗
PubMed1988

Improved assay for bismuth in biological samples by atomic absorption spectrophotometry with hydride generation.

This simple, rapid, sensitive, reliable, and economical assay for bismuth in plasma, erythrocytes, and urine is based on atomic absorption spectrophotometry with hydride generation. Acid digestion eliminates the problem of foaming, which hitherto has complicated such assay of bismuth in plasma and erythrocytes. The detection limit of the assay has been improved to 0.1 micrograms/L, as compared with a previously documented limit of 2.5 micrograms/L. Average recovery exceeded 95% in all biological fluids. Economy of use derives from elimination of need for electrodeless discharge lamps and atomic absorption grade borohydride. Determination of basal concentrations of bismuth in clinical samples of body fluids gave reference intervals of 0.1-3.5 micrograms/L for plasma, 0.3-4.6 micrograms/L for urine.

Adult↗
PubMed1988

[Measurement of cerebral blood volume by reflections spectrophotometry: methodological improvement and quantitative evaluation].

The authors described methodological improvement and quantitative evaluation in measurement of cerebral blood volume (CBV) by reflectance spectrophotometry. The measurement of blood volume by this method has not been applied to the brain tissue because of the methodological difficulties. In order to obtain the accurate CBV values with this method, it is necessary to keep the proper contact between the sensor for the measurement and the brain tissue to be measured. For this purpose we developed a balance arm. A sensor for CBV measurement was fixed with the one side of the arm and a weight was installed to the other side. The pressure of the sensor to the brain can be adjusted by moving the weight, and the sensor was placed on the brain tissue with the proper pressure. Moreover, the sensor was attached with an acryl-made cap to make the pressure adjustment easier by enlarging the contact surface and to enable to observe the vasculature on the surface of the brain. With this improved method the reasonable changes of CBV could be obtained when the CO2 gas was inhalated and cerebral ischemia was produced in cats. The possibility of the quantitative evaluation was investigated using the homogenized brain tissue of cats. After the elimination of the blood from the brain by the perfusion with the saline, the brain was removed and homogenized. Then, the definite volume of blood, of which hemoglobin volume was already known, was added and measured by this method.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Measurement of trace levels of total aluminum in foods by atomic absorption spectrophotometry.

A graphite furnace atomic absorption spectrophotometry method was used to determine the total aluminum content of various foods found in an average American diet. The food products were ashed in platinum dishes, and the inorganic residue was fused using a sodium carbonate-sodium borate mixture. The fusion step allowed detection of all the various forms of aluminum found in food products. A L'vov platform was used in the graphite furnace to increase the sensitivity of the assay. Care was taken throughout the analysis to avoid various sources of aluminum contamination such as glass and porcelain dishes. All reagents were ultra-pure grade and were continuously monitored for aluminum content. Sodium borate used in the fusion flux mixture had previously been extracted with 8-hydroxyquinoline in chloroform to remove any aluminum present. Both raw and cooked foods were analyzed for aluminum with this method. Average recoveries of aluminum from food products ranged from 84 to 112%. The overall coefficient of variation of this method on the food products tested was 10%.

Aluminum↗
PubMed1987

Determining methemoglobin in blood by zero-crossing-point first-derivative spectrophotometry.

We determined methemoglobin in blood by zero-crossing-point first-derivative spectrophotometry. After lysis of erythrocytes, hemoglobin was converted into oxyhemoglobin and the first derivative spectrum was recorded between 405 and 425 nm. At the exact point where the first-derivative spectrum of oxyhemoglobin was zero ("zero-crossing point"), the first-derivative value of oxyhemoglobin and methemoglobin mixture was proportional to the methemoglobin concentration. The standard curve was linear for all proportions of methemoglobin. Within-assay precision (CV) was 3.4% for a 20% methemoglobin content. Correlation with results by the Evelyn and Malloy method was very good for high proportions of methemoglobin (greater than 10%), but the proposed technique was far better for low methemoglobin percentages because of its linearity, its high sensitivity, and its low detection limit.

Humans↗
PubMed1987

Optimized atomic absorption spectrophotometry of calcium in erythrocytes.

We sought to establish optimum conditions for measuring calcium in erythrocytes by atomic absorption spectrophotometry. The conditions we selected are as follows. Wash one volume of fresh heparin-treated packed cells once with 30 volumes of isotonic buffered saline (pH 7.4) at a temperature somewhat exceeding 25 degrees C. Dilute the washed packed cells 10-fold with 12 mmol/L hydrochloric acid, and analyze the supernate for calcium. Measure the hematocrit of the washed packed cells, then analyze an aliquot of them for calcium, using a computer-readout type of flame or a non-flame atomic absorption spectrophotometer equipped with a pyrocoated graphite tube. The temperature program is 1000 degrees C for ashing [corrected] and 1800 degrees C for the atomizing cycle. Intraday and day-to-day reproducibility of the assay was 6.55% and 8.19%, respectively, at the mean concentration of calcium in the erythrocytes of healthy adults, which is 4.30 mumol/L.

Adult↗
PubMedDate not supplied

Rapid analysis of nickel in urine by electrothermal atomic absorption spectrophotometry.

A method is described for analysis of nickel in urine, which involves dilution of urine with dilute nitric acid and direct quantitation of nickel by electrothermal atomic absorption spectrophotometry with Zeeman background correction. The detection limit for nickel is 0.5 micrograms per L of urine; the coefficient of variation of replicate determinations is 4 to 5 percent (within-run) and 6 percent (run-to-run). Recovery of nickel added to urine (20 micrograms per L) averages 99 +/- 5 percent (mean +/- SD). Analytical results agree closely with measurements by the International Union of Pure and Applied Chemistry (IUPAC) reference procedure (correlation coefficient = 0.99). Nickel concentrations in urine specimens from 34 non-exposed, healthy, adult persons living in Connecticut average 2.0 +/- 1.5 microgram per L (range = 0.5 to 6.0 micrograms per L). Urine nickel concentrations are directly correlated with urine creatinine concentrations and specific gravity measurements. Elevated concentrations of nickel are observed in urine specimens from nickel-exposed workers, including nickel electroplating workers (mean = 27 micrograms per L, range = 3.1 to 82 micrograms per L, N = 19) and nickel battery workers (mean = 32 micrograms per L, range = 2.8 to 103 micrograms per L, N = 7). This method is more rapid and convenient than previous techniques and is suitable for routine use in clinical and industrial laboratories.

Creatinine↗
PubMed1986

Use of the caffeine reagent in direct spectrophotometry of bilirubin.

The molar absorptivity of unconjugated bilirubin in caffeine reagent is independent of the protein matrix. This finding, together with the simplicity of a dilution step for direct spectrophotometry, will improve the calibration methods of bilirubin and make them more nearly accurate. This is encouraging for the development of a new method for bilirubin determination in neonates; moreover, the caffeine reagent has a clearing influence on the turbidity of human sera. These findings should also be important for standardization, especially because the method of Jendrassik and Gróf is also protein-independent. Therefore, the introduction of one reliable, inexpensive, "universal" standard of bilirubin in bovine serum albumin will be of importance for both methods.

Bilirubin↗