Determination of anti-malaria agent chloroquine using single drop liquid-liquid-liquid microextraction.

A simple, sensitive, and inexpensive single drop liquid-liquid-liquid microextraction combined with isocratic RP-HPLC and UV detection was developed for the determination of anti-malaria drug, chloroquine. The target compound was extracted from alkaline aqueous sample solution (adjusted to 0.5 mol/L sodium hydroxide) through a thin layer of organic solvent membrane and back-extracted to an acidic acceptor drop (adjusted to 0.02 mol/L phosphoric acid) suspended on the tip of a 25 microL HPLC syringe in the organic layer. This syringe was also used for direct injection after extraction. The linear range was 1-200 microg/L. The LOD and LOQ were 0.3 and 1.0 microg/L, respectively. Intra-and inter-day precisions were less than 2.0 and 2.3%, respectively. The real samples were successfully analyzed using the proposed method. The recoveries of spiked samples were more than 94.6%.

Contrasting occurrence of Chromobacterium violaceum in tropical drinking water springs of Uganda.

Occurrence of Chromobacterium violaceum in six protected drinking water springs in Uganda was investigated. C. violaceum showed a contrasting occurrence, which was independent of human impact as assessed by faecal pollution indicators. It was isolated from two springs (S1 and S2) that were located close to each other (3 km) but not in the rest. In S1 C. violaceum was continuously detected, in concentrations ranging from 6 to 270 cfu 100 ml(-1), while in S2 it was detected on only one sampling occasion. C. violaceum was never detected in the investigated upper soil layers (down to 15 cm) in the immediate surroundings (50 m radius) of the springs, despite continued isolation of faecal indicators. The results of the study indicate that C. violaceum may not be ubiquitous in spring water, but could occur in significant numbers in particular potable groundwaters as an autochthonous member.

Discrimination efficacy of fecal pollution detection in different aquatic habitats of a high-altitude tropical country, using presumptive coliforms, Escherichia coli, and Clostridium perfringens spores.

The performance of rapid and practicable techniques that presumptively identify total coliforms (TC), fecal coliforms (FC), Escherichia coli, and Clostridium perfringens spores (CP) by testing them on a pollution gradient in differing aquatic habitats in a high-altitude tropical country was evaluated during a 12-month period. Site selection was based on high and low anthropogenic influence criteria of paired sites including six spring, six stream, and four lakeshore sites spread over central and eastern parts of Uganda. Unlike the chemophysical water quality, which was water source type dependent (i.e., spring, lake, or stream), fecal indicators were associated with the anthropogenic influence status of the respective sites. A total of 79% of the total variability, including all the determined four bacteriological and five chemophysical parameters, could be assigned to either a pollution, a habitat, or a metabolic activity component by principal-component analysis. Bacteriological indicators revealed significant correlations to the pollution component, reflecting that anthropogenic contamination gradients were followed. Discrimination sensitivity analysis revealed high ability of E. coli to differentiate between high and low levels of anthropogenic influence. CP also showed a reasonable level of discrimination, although FC and TC were found to have worse discrimination efficacy. Nonpoint influence by soil erosion could not be detected during the study period by correlation analysis, although a theoretical contamination potential existed, as investigated soils in the immediate surroundings often contained relevant concentrations of fecal indicators. The outcome of this study indicates that rapid techniques for presumptive E. coli and CP determination may be reliable for fecal pollution monitoring in high-altitude tropical developing countries such as those of Eastern Africa.