Contribution to diagnostics/prognostics of tuberculosis in children. II. Indicative value of metal ions and biochemical parameters in serum.

Newly introduced methods of assaying simultaneously copper and zinc and zinc alone in serum by flame atomic-absorption spectrometry are simple and economical, especially in saving the consumption of serum material. Along with biochemical parameters, they have been successfully applied to diagnostics/prognostics of tuberculosis in children, through analyses of sera from pediatric patients with lung tuberculosis or suspected tuberculosis, enabling the follow-up of therapeutic efficiency. The prognostic strength of Cu and Cu/Zn ratio together with C-reactive protein, complement components C3 and C4, and erythrocyte sedimentation rate have been documented.

Contribution to diagnostics/prognostics of tuberculosis in children. I. New methods of assaying zinc and simultaneously copper and zinc in diluted sera by flame atomic-absorption spectrometry.

In an attempt to provide a reliable status of metal ions in children, new methods of analysis of children's sera are proposed. New flame atomic-absorption spectrometric (FAAS) methods are simple, cost- and time-effective and, above all, labor-, reagent- and sample-saving. Two methods were suggested: method A for simultaneous determination of Cu and Zn from 5-fold diluted sera, and method B, for assaying zinc alone in 10-fold diluted samples.

Comparison of spectrophotometric and HPLC methods for determination of carotenoids in foods.

This report is aimed at intra-laboratory and inter-laboratory comparison of the results obtained during spectrophotometric and HPLC analyses of lycopene, β-carotene and total carotenoids in tomato products and yellow maize flours/grits. Extensive statistical analyses are performed in order to identify the main sources of uncertainties which may occur when using: (i) different techniques/methods/approaches in the same/different laboratories, in various food samples, and (ii) to indicate the facts/conditions under which the biases between results may remain unidentified after applying statistical testing. Our data points to the inertness of t-test to detect significance of differences, particularly at low R values: in general, the higher correlation coefficient, the higher is sensitivity of statistical testing, especially of the paired t-test.

Assaying Total Carotenoids in Flours of Corn and Sweetpotato by Laser Photoacoustic Spectroscopy.

This study describes the application of the laser photoacoustic spectroscopy (PAS) for quantification of total carotenoids (TC) in corn flours and sweetpotato flours. Overall, thirty-three different corn flours and nine sweetpotato flours were investigated. All PAS measurements were performed at room temperature using 488-nm argon laser radiation for excitation and mechanical modulation of 9 and 30 Hz.

Simultaneous determination of iron and copper in children's sera by FAAS.

A new and simple flame atomic-absorption spectrometric (FAAS) method is proposed for simultaneous determination of iron and copper in children's sera. It is based on single-step sample pretreatment (deproteinization with 3 mol L-1 HCl, ratio 1:1) and single-step calibration using 1.5 mol L-1 HCl standard.

Direct photothermal techniques for rapid quantification of total anthocyanin content in sour cherry cultivars.

The analytical performance of the newly proposed laser-based photoacoustic spectroscopy (PAS) and of optothermal window (OW) method for quantification of total anthocyanin concentration (TAC) in five sour cherry varieties is compared to that of the spectrophotometry (SP). High performance liquid chromatography (HPLC) was used to identify and quantify specific anthocyanins. Both, PAS and OW are direct methods that unlike SP and HPLC obviate the need for the extraction of analyte.

Spectrophotometric estimation of total carotenoids in cereal grain products.

Total carotenoids (TC) were determined as a measure of total xanthophylls in grain flours and grits, by new validated spectrophotometric method based on A1cm1%-approach. The general analytical procedure is easily adjustable to different samples, the number of extraction steps depending on TC concentration in the sample. Basically, two methods have been suggested: the rapid one for low-TC samples (white corn, wheat, soybean, sorghum) including one to two extractions, and the one for high-TC samples (yellow corn) needing three to four extractions.

Correlation of trans-Lycopene Measurements by the HPLC Method with the Optothermal and Photoacoustic Signals and the Color Readings of Fresh Tomato Homogenates.

The trans-lycopene content of fresh tomato homogenates was assessed by means of the laser photoacoustic spectroscopy, the laser optothermal window, micro-Raman spectroscopy, and colorimetry; none of these methods require the extraction from the product matrix prior to the analysis. The wet chemistry method (high-performance liquid chromatography) was used as the absolute quantitative method. Analytical figures of merit for all methods were compared statistically; best linear correlation was achieved for the chromaticity index a* and chroma C*.

New simple spectrophotometric assay of total carotenes in margarines.

Direct and reliable spectrophotometric method for assaying total carotenes (TC) in margarines with the minimum of sample manipulation is proposed. For the first time saponification step used in determination of carotenes in margarines was omitted leading to a substantial cost saving and reduction of time needed to complete the analysis. The resulting analytical procedure is characterized in details in terms of the figures of merit.

Optothermistor as a breakthrough in the quantification of lycopene content of thermally processed tomato-based foods: verification versus absorption spectrophotometry and high-performance liquid chromatography.

This study reports on the first use of the "optothermistor" as a novel, precise, fast, and low-cost detector of lycopene in a wide range of commercially available processed-tomato products. The quantitative performance of the new device was evaluated by comparing data obtained to that acquired by conventional methods, namely, absorption spectrophotometry and high-performance liquid chromatography (HPLC); the linear correlation was high (R = 0.98).

Direct quantification of lycopene in products derived from thermally processed tomatoes: optothermal window as a selective, sensitive, and accurate analytical method without the need for preparatory steps.

The concept of the optothermal window (OW) is proposed as a reliable analytical tool to rapidly determine the concentration of lycopene in a large variety of commercial tomato products in an extremely simple way (the determination is achieved without the need for pretreatment of the sample). The OW is a relative technique as the information is deduced from the calibration curve that relates the OW data (i.e.