Online detection of alkanes by a biological-phase microextraction and biosensing (BPME-BS) device.

Oil spill incidents occur frequently and threaten ecosystems and human health. Solid-phase microextraction allows direct alkane extraction from environmental matrices to improve the limit of detection but is unable to measure alkanes on site. A biological-phase microextraction and biosensing (BPME-BS) device was developed by immobilising an alkane chemotactic Acinetobacter bioreporter ADPWH_alk in agarose gel to achieve online alkane quantification with the aid of a photomultiplier. The BPME-BS device had a high enrichment factor (average 7.07) and a satisfactory limit of detection (0.075 mg/L) for alkanes. The quantification range was 0.1–100 mg/L, comparable to a gas chromatography flame ionisation detector and better than a bioreporter without immobilisation. ADPWH_alk cells in the BPME-BS device maintained good sensitivity under a wide range of environmental conditions, including pH (4.0–9.0), temperature (20–40 °C), and salinity (0.0–3.0%), and its response remained stable within 30 days at 4 °C. In a 7-day continual measurement, the BPME-BS device successfully visualised the dynamic concentration of alkanes, and a 7-day field test successfully captured an oil spill event, helping in source apportionment and on-scene law enforcement. Our work proved that the BPME-BS device is a powerful tool for online alkane measurement, showing substantial potential for fast detection and rapid response to oil spills on site and in situ. [Display omitted] • First alkane online detection device using immobilized bioreporters. • Detection limit of 0.075 mg/L and quantification range of 0.1–100 mg/L for alkanes. • Stable performance under pH 4.0–9.0, temperature 20–40 °C, salinity 0.0–0.3%. • Long shelf-life of 30 days at 4 °C. • Successful oil spill recognition in field test for water quality management. [ABSTRACT FROM AUTHOR]