Transition on the entropic elasticity of DNA induced by intercalating molecules

We use optical tweezers to perform stretching experiments on DNA molecules when interacting with the drugs daunomycin and ethidium bromide, which intercalate the DNA molecule. These experiments are performed in the low-force regime from zero up to 2 pN. Our results show that the persistence length of the DNA-drug complexes increases strongly as the drug concentration increases up to some critical value. Above this critical value, the persistence length decreases abruptly and remains practically constant for larger drug concentrations. The contour length of the molecules increases monotonically and saturates as drugs concentration increases. Measured in- tercalants critical concentrations for the persistence length transition coincide with reported values for the helix-coil transition of DNA-drug complexes, obtained from sedimentation experiments.Comment: This experimental article shows and discuss a transition observed in the persistence length of DNA molecules when studied as a function of some intercalating drug concentrations, like daunomycin and ethidium bromide. It has 15 pages and 4 figures. The article presented here is in preprint forma

In-line phosphate pre-concentration in a flow injection method platform for monitoring fertilizers excess in soil leachates

info:eu-repo/semantics/publishedVersio

Improvement of a sequential injection method for the determination of chromium (VI) in waters using a GlobalFIA platform.

info:eu-repo/semantics/publishedVersio

Microfluidic paper-based devices as disposable, easy-to-use, real time quantification methods

info:eu-repo/semantics/publishedVersio

Monitoring soil/water interface: development of an integrated sequential injection system applied to laboratory scale soli core column and micro soil column

info:eu-repo/semantics/publishedVersio

The State of the Art of Flow-Through Solid-Phase Spectrometry

Sample pretreatment is one of the bottlenecks in analytical chemistry, especially when dealing with complex matrices like environmental samples. When performed in a batch mode, sample handling methods are tedious and time consuming. Therefore, the hyphenation of these methods with flow-injection techniques yields many advantages. The possibility of automation not only increases the determination rate, but also decreases sample and reagent consumption. As a consequence, analyte separation, enrichment, and elimination of sample matrix becomes possible with an increase in selectivity and sensitivity. This is a significant contribution for the analysis of environmental samples because the analyte is usually present at trace levels in a complex matrix. In this scenario, the state of the art of solid-phase spectrometry (SPS) with a focus on the lab-on-valve (LOV) platform is discussed. LOV facilitates the manipulation of bead suspension for SPS with lower reagents consumption and waste production.info:eu-repo/semantics/publishedVersio