Miniaturized total analysis systems for biological analysis

This review article discusses and documents the basic philosophies, concepts and current advances in the field of micro-TAS development, with special emphasis on applications in the arena of biosciences. After a brief overview of miniaturization theory and fabrication techniques, areas of microfluidic component development, detection protocols, biochemical assays, and integrated biological analyses are addressed.     

Vibrational analysis and normal coordinate analysis of trimethylphosphane

Raman spectra of trimethylphosphine {P(CH₃)₃} as liquid have been recorded with parallel and perpendicular polarization. Vibrational assignments are given by means of a normal coordinate analysis. The skeletal modes of the phosphoruscarbon-core and their interactions with the methyl groups, its force field and potential energy distribution are discussed.     

Kinetic analysis of derivative curves in thermal analysis

Two methods of obtaining kinetic parameters from derivative thermoanalytical curves are proposed. The methods are based on the general form of kinetic formulae and are applicable to general types of reactions governed by a single activation energy. One method utilizes the linear relation between peak temperature and heating rate in order to estimate the activation energy, and only the information of the rate of conversion versus the temperature is necessary. The other method needs the information of both the conversion and the rate of conversion versus the temperature, and the Arrhenius plot is made for an assumed kinetic mechanism.

     

Approaches to bioresponse-linked instrumental analysis in water analysis

A new concept based on hyphenation of biotests, for biological selection, and chemical analysis is introduced for water analysis. Biomolecular recognition components such as receptors, enzymes, and nucleic acids integrated in biological reaction chains are used for binding and selective enrichment of known and unknown biologically active substances in water samples; this is followed by identification and quantitation. The coupling of biomolecular recognition and binding to chemical analysis can be achieved either in discrete analytical steps, e.g. binding and elution of bioactive ligands from affinity columns followed by chemical analysis, or by methods capable of monitoring the binding of the ligand and simultaneous verification of its identity. This analytical strategy, denoted bioresponse-linked instrumental analysis (BLIA), enables detection of potential biological effects and identification of the analyte causing these effects. Several examples are presented.     

Different approaches to proximate analysis by thermogravimetry analysis

The experimental optimization by the simplex method of the proximate analysis of coal and biomass by thermogravimetry analysis (TGA) is reported. Heating rate, final temperature, holding time, Ar flow rate and sample size were the control variables. The response function used was chosen to minimize the difference in percentage of volatile matter with the ASTM characterization. The relative accuracy of the method was demonstrated by determination of the volatile matter contents of a number of coals in parallel with the ASTM certified method. The method is successfully used with biomass samples.     

Low level mercury analysis by neutron activation analysis

During the years 1974–77 about 200 low level mercury analyses on samples with less than 1000 ng Hg/kg were made at the Danish Isotope Centre. This paper describes our method of neutron activation analysis for low level mercury analysis. The accuracy of the mercury analyses is shown by the results of the determinations on NBS standard, SRM 1642, and on intercalibration analyses. The accuracy found is better than 10% for samples with about 100–300 ng Hg/kg and better than 10 ng Hg/kg for samples with less than 100 ng Hg/kg. The limit of detection for the analyses is about 1–5 ng Hg/kg, depending on the sample and the exact method of analysis. The lowest standard deviations on duplicate analyses are about 1 ng Hg/kg. The general level found in sea water is about 10 ng Hg/kg, in ground water about 50 ng Hg/kg, and in rain water about 100 ng Hg/kg.     

Web-based spectrum analysis software for photon activation analysis

Photon activation analysis (PAA) includes extensive data evaluation that is sensitive to error. In order to save time and minimize human error, a new computer program—photon activation analysis system (PAAS)—was designed, built and implemented using the SQL language and Asp.net technology to analyze PAA data. Given peak information from PAA spectra and aided by a photonuclear data library, the program identifies the product isotopes, recognizes the possible nuclear reactions, and evaluates the concentration of target elements. Uncertainties of concentrations are estimated using standard error propagation techniques. The program can be accessed conveniently anywhere the internet is available and gives a fast and reliable determination of the trace elemental content of samples. Furthermore, this program also allow one to search its database for the information of general photonuclear reactions (e.g. energy lines, line intensities, target and product nuclides, photonuclear reactions, cross sections, natural abundance, etc.) and estimating the activity even before the activation begins. By switching the nuclide libraries, the program could also be expanded to neutron activation analysis and charged particle activation analysis (CPAA) without any difficulty. This program can be a versatile tool for the daily use of the nuclear and radiochemistry laboratories that conduct activation analysis.     

Inorganic analysis

AbstractsGeneral analytical chemistry

Inorganic analysis     

Thermodielectrical analysis

The paper presents an application of thermodielectrical analysis in a geological material of industrial interest (bentonites). Thermodielectrical curves show noticeable differences in dependence of the cationic content and chemical nature of the cations, and also, with the cation position in the lattice.     

Inorganic analysis

AbstractsGeneral analytical chemistry

Inorganic analysis     

Thermogravimetric analysis

Waterlogged archaeological woods (Pinus pinaster, Ulmus cf. minor and Fagus sylvatica L.) were consolidated by using Colophony, Rosin 100, and a mixture of Poly(ethylene) glycol (PEG) 3000 and Poly(propylene) glycol (PPG) 425. The efficiency of the consolidants was estimated by determining the content entrapped into the cavity of degraded wood. For this purpose, thermogravimetry was demonstrated to be a reliable tool. In the case that the polymeric mixture was used for impregnation, it was also possible to discriminate the amount of PEG 3000 from that of PPG 425 captured by the wood capillaries. Regardless of the wood nature, all the consolidants were present in treated samples in large amount (at least 70% w/w). Thermogravimetric results were in agreement with those calculated by using the wood degradation degree and composition of the consolidant mixture. One of the advantages of using this technique consists into requiring very small amounts (a few mg) of sample against the grams necessary for the conventional experiments.