A microfluidic hollow fiber membrane extractor for arsenic(V) detection.

Microfluidic membrane extraction using a conventional hollow fiber membrane is presented for continuous, on-line extraction of arsenic. Previously reported micro-scale devices used flat membranes. These modules were relatively complex, difficult to seal, and high pressure drops made them prone to leaks. The present design is simpler, has higher active surface area per unit volume, and allows faster flow rates leading to enhanced mass transfer. On-line membrane extraction of As(V) via chelation through a supported liquid membrane was followed by conventional colorimetric detection with a UV-vis spectrophotometer. Enrichment factors were close to 30, and the detection limit was 27 microg L(-1). The extraction was linear and reproducible. The relative standard deviation of six repeat extractions was less than 3%.