The hierarchy and relationships of analytical properties

Usefulness of Analytical Research: Rethinking Analytical R&D&T Strategies

This Perspective is intended to help foster true innovation in Research & Development & Transfer (R&D&T) in Analytical Chemistry in the form of advances that are primarily useful for analytical purposes rather than solely for publishing. Devising effective means to strengthen the crucial contribution of Analytical Chemistry to progress in Chemistry, Science & Technology, and Society requires carefully examining the present status of our discipline and also identifying internal and external driving forces with a potential adverse impact on its development. The diagnostic process should be followed by administration of an effective therapy and supported by adoption of a theragnostic strategy if Analytical Chemistry is to enjoy a better future.

Bridging the gap between analytical R&D products and their use in practice

Identifying the key stakeholders (viz. R&D centers, routine laboratories, clients and producers of analytical tools) and their mutual relationships in Analytical Science, and pinpointing the objects through which knowledge and technology can be transferred among them, can help one recognize the weaknesses in the links connecting 'ivory towers' and industry with a view to developing ways to bridge the existing gap between the two.

Estimation and correction of matrix effects in gas chromatographic pesticide multiresidue analytical methods with a nitrogen-phosphorus detector

The assessment of matrix effects in the quantification of organophosphorus pesticides in fruit and vegetables by GC-NPD, were studied applying ANCOVA. Calibration curves prepared in solvent were compared with calibration curves prepared in a blank matrix extract for eight different commodities, establishing whether the matrix induces systematic or proportional errors in the quantification of the pesticides. In such cases correction functions were obtained and validated by quantifying spiked samples using solvent calibrations and applying the correction functions to the data obtained. The results were compared with those obtained by quantification using matrix-matching calibrations and with those from 100% recovery experiments. It was found that the matrix effects can be avoided using the correction functions. Finally the contribution of the correction functions to the uncertainty of the results was estimated as well as their stability during a four month period.

Coupling continuous separation techniques to capillary electrophoresis

One of the weak points of capillary electrophoresis is the need to implement rigorously sample pretreatment because its great impact on the quality of the qualitative and quantitative results provided. One of the approaches to solve this problem is through the symbiosis of automatic continuous flow systems (CFSs) and capillary electrophoresis (CE). In this review a systematic approach to CFS-CE coupling is presented and discussed. The design of the corresponding interface depends on three factors, namely: (a) the characteristics of the CFS involved which can be non-chromatographic and chromatographic; (b) the type of CE equipment: laboratory-made or commercially available; and (c) the type of connection which can be in-line (on-capillary), on-line or mixed off/on-line. These are the basic criteria to qualify the hyphenation of CFS (solid-phase extraction, dialysis, gas diffusion, evaporation, direct leaching) with CE described so far and applied to determine a variety of analytes in many different types of samples. A critical discussion allows one to demonstrate that this symbiosis is an important topic in research and development, besides separation and detection, to consolidate CE as a routine analytical tool.

Immunoassays in monitoring biotechnological drugs

For the evaluation and interpretation of pharmacokinetic data reliable quantitative determinations are a requirement that can only be met by well-characterized and fully validated analytical methods. To cope with these requirements a method is being established that is based on an integrated and automated fiber-optic biospecific interaction analysis system (FOBIA) for immunoassays. Performance characteristics of this system used in monitoring of recombinant hirudin (CGP 39 393) are presented. Recombinant hirudin is a highly potent and selective inhibitor of human thrombin. Owing to its size and charge, recombinant hirudin is mainly eliminated by glomerular filtration. But only a fraction of the hirudin dose seems to be reabsorbed at the proximal tubule by luminal endocytosis and hydrolyzed by lysosomal enzymes, leaving approximately 50% of the dose to be extracted in the urine. Thus, renal clearance of recombinant hirudin in the absence of renal insufficiency appears to depend primarily on the glomerular filtration rate. During a 3-month i.v. tolerability study in dogs, some of the dogs developed antibodies against recombinant hirudin. The hirudin-antibody complex accumulated in plasma and apparent hirudin plasma concentrations were therefore much higher than expected from single-dose kinetics. Hirudin captured by antibodies showed an extended half-life and the hirudin-antibody complex is still pharmacologically active, as demonstrated by the observed increase in thrombin time. In conclusion, only appropriate analytical methods allow adequate monitoring and pharmacokinetic characterization of biotechnology drugs in biological materials.