Scielo RSS http://www.scielo.org.za/rss.php?pid=0379-435020230001&lang=en vol. 77 num. lang. en http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0379-43502023000100001&lng=en&nrm=iso&tlng=en A simple, fast, low-cost and sensitive microfluidic paper-based analytical device (u-PADs) integrated with the co-precipitation enrichment procedure was developed to analyse Ni(II) in tap and mineral water samples. The impacting factors, including pH, centrifugation (5 min at 4000 rpm), and amounts of reagents were optimized. The limit of detection of 0.009 mg L-1 and linear range of 0.03-2.00 mg L-1 were achieved with good intra- and inter-day precision (4.7 and 5.6% RSD, respectively). The recovery tests were conducted by spiking tap and mineral water samples and analyzed using the u-PADs after co-precipitation enrichment. The results obtained by the proposed method were validated by inductively coupled plasma-optical emission spectrometry (ICP-OES). The recoveries of the present method and ICP-OES were ranged from 92.4-106.8% and 92.9-97.2%, respectively. The two sets of (u-PADs and ICP-OES) results were in good agreement, as a paired t-test indicated no significant differences. The proposed method could be utilized for analyzing trace levels of Ni(II) in water samples in developing countries where the availability of conventional analytical instruments are significant problems. http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0379-43502023000100002&lng=en&nrm=iso&tlng=en Two series of coupled heterocyclic systems have been synthesised and found to be efficacious against the NF54 chloroquine sensitive strain of P. falciparum in an in vitro assay. Quinolines were coupled with benzofurans in the first series and benzothiophenes in the second series. Compounds with an amide linkage are more efficacious by one order of magnitude than the ester equivalent. No other clear pattern was discernible. Compounds were also tested for toxicity using an MTT assay. All compounds tested showed selectivity towards P. falciparum. Barring one, all compounds tested showed greater efficacy than chloroquine against β-hematin inhibition. But no correlation was observed between β-hematin inhibition and efficacy against P. falciparum.