SouthWestSensor's DropletSens™ platform brings the analytical precision of the wet-chemical laboratory directly into the field. By utilizing advanced microfluidics, our autonomous in-situ sensors deliver continuous, high-frequency measurements of ammonium, orthophosphate, nitrate, and nitrite, providing the dense, high-fidelity datasets required to power modern ecological models and peer-reviewed research.

Unlocking High-Resolution Nutrient Dynamics in Natural Waters


 

Whether studying nutrient cycling in pristine headwaters, tracking agricultural eutrophication run-off, or mapping estuarine mixing zones, researchers require sensors that can operate across highly dynamic concentration gradients.

Traditional optical or electrochemical probes often lack the specificity or lower limits of detection (LOD) required for scientific study, particularly in low-nutrient oligotrophic waters. SWS in-situ sensors provide high-frequency sampling (up to every 10 seconds), capturing transient pollution pulses, diurnal biological drawdowns, and catchment-scale nutrient mapping with unparalleled temporal resolution.

Proven Wet-Chemistry Methods Scaled to Nanodroplets


 

Scientific data must be defensible. To ensure seamless correlation with historical datasets and regulatory laboratory standards, the DropletSens™ platform scales gold-standard, peer-reviewed colorimetric chemistry down to a microfluidic chip:

  • Nitrate & Nitrite: Based on the globally established Griess test, determining nitrite and nitrate autonomously in series.
  • Ammonium & Ammonia: Utilizes the classic Berthelot reaction and indophenol chemistry, measuring total ammonia nitrogen (TAN) through precise, pH-mediated conversion.
  • Phosphate & Orthophosphate: Employs the definitive Molybdenum Blue method to isolate and measure dissolved reactive phosphorus (orthophosphate)—a measurement where electrochemical or spectral probes are chemically blind.

Eliminating Sensor Drift with Automated On-Device Standards

For long-term spatial and temporal monitoring, sensor calibration drift is a primary threat to data integrity. Traditional field sensors require frequent physical retrieval, manual cleaning, and laboratory recalibration.

SWS eliminates manual calibration overheads through a fully automated QC process:

  • On-Board Standards: Every DropletSens™ unit is equipped with a sealed calibration standard. The sensor automatically runs routine performance checks at user-defined intervals, self-correcting for any drift in real-time.
  • Fouling Prevention: Because the chemical reaction occurs entirely inside isolated microchannels, the delicate optical components never come into direct contact with the raw sample matrix, preventing the biofouling that degrades standard optical sensors.
  • Defensible Data Trails: Every raw measurement is stored alongside automated calibration data, providing an unbroken, audit-ready metadata record that satisfies the most rigorous peer-review and open-data standards.

Optimised for Remote, Off-Grid, and Mobile Field Deployments

Fieldwork often takes researchers to remote, inaccessible locations. SWS technology is engineered to minimize the physical and energy footprint of remote sensor deployment:

  • 90-Day Autonomous Deployment: Due to nanodroplet-scale chemistry, reagent consumption is microscopic. A single reagent cartridge supports up to 3 months of continuous field operation (at standard 15-minute intervals) before requiring an easy cartridge swap.
  • Ultra-Low Power Draw: Consuming only 1.5 Watts during continuous sampling cycles, SWS systems run effortlessly on small, off-grid solar panels or compact battery packs.
  • Versatile Integration: Stream real-time data directly to your database via Modbus, RS232/RS485, or Bluetooth. SWS sensors are designed for integration into bankside kiosks, moored oceanographic buoys, or mobile catchment-mapping platforms (including WATR’s floatable research rigs).