Resumo

HERRERA, Dubraska et al. Calibrated metallic loops for microbiologists: A nationally manufactured alternative. Rev. Soc. Ven. Microbiol. [online]. 2010, vol.30, n.1, pp.37-42. ISSN 1315-2556.

Calibrated metallic loops for the quantification of bacterial colony forming units transfer an “exactly known” sample volume and have been extremely important tools for quality control, research and clinical laboratories. The loops marketed in our country are imported and mostly made of nickel-chrome alloy. This has created the need for searching for low cost national alternatives. In this work we propose the manufacture of these loops with commercial nickel-chrome wire equivalent to the commercial platinum and nickel-chrome loops, at lower costs. The loops were comparable in performance and appearance. All the loops were calibrated using two methods (gravimetric and colorimetric) with 45^o and 90^o charge angles. An experimental design with factorial treatment arrangement 2³ (calibration method-loop type-charge angle with 4 repetitions) was used. A 672 data variance analysis and comparison of means (Tukey’s test) were carried out, and Bonferroni’s confidence intervals of the standard deviations were calculated. It was demonstrated that the artisan loops emulated the commercial ones, representing a low cost national alternative for obtaining these instruments.

Palavras-chave : calibrated loops; nickel-chrome loops.