US 11,378,541 B1Granted

Self-contained, automated, long-term sensor system for monitoring of soil and water nutrients in fields

AssigneeIowa State University Research Foundation, Inc.

InventorsLiang Dong, Yueyi Jiao, Yuncong Chen, Azahar Ali, Xinran Wang

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Abstract

An automated, fieldable ion-selective sensor system for frequent detection of nutrients in soils or water is set forth. In one aspect, an integrated small form-factor housing includes a battery, processor, a fluid manipulation unit and reservoirs, and a chemical species detection cell. A flow-through sampling head can be connected to the detection cell and a waste reservoir by flexible tubing sealingly connected at opposite ends of the tube. In one aspect, improved performance of the ion-selective sensor includes adding an ion-to-electron transfer interlayer between an ion-selective membrane and its working electrode. In one aspect, the sensor is solid-state and uses printed polymeric composite of POT-MoS2. The use of a porous tube for a sampling head and fluid connection at opposite ends allows not only fluid to be removed from the head to the detection cell for measurement but also flow in an opposite direction and out to a waste reservoir to clean and reset for a next sample measurement.

Claims22

Dependent claims

A system for self-contained, long term monitoring of soil and water nutrients in fields comprising:

(a) a soil sampling head, the sampling head comprising:
(i) a tube having at least a portion of its sidewall between opposite open ends which is gas/fluid permeable;
(ii) fluid connectors sealed at the opposite open ends of the tube;
(iii) the tube and connectors adapted to be placed in situ into soil or water at a measuring depth;
(b) a ruggedized housing including:
(i) a biochemical detection subsystem comprising:
(1) a sealed detection cell;
(2) at least one electrochemical sensor in the detection cell;
(ii) a fluid manipulation subsystem comprising:
(1) a soil water extraction and delivery fluid circuit comprising:
a. a vacuum pump in fluid communication with the detection cell;
b. a fluid conduit from a connector at one end of the tube in the soil water sampling head to the detection cell in the housing;
c. wherein selective operation of the vacuum pump during a sampling and detection cycle promotes collection of soil water/air in the soil sampling head and flow to the detection cell for biochemical sensing through the said connector at one end of the tube;
(2) a system reset/reconditioning/recalibrating fluid circuit comprising:
(a) a cleaning liquid reservoir and actuator to move cleaning fluid to the detection cell;
(b) a waste liquid reservoir and actuator to move fluid in the tube to the waste liquid reservoir;
(c) a recalibration liquid reservoir and actuators to move fluid to the detection cell and the waste liquid reservoir;
(d) wherein selective operation of the actuators during a cleaning/reset/reconditioning cycle moves cleaning fluid through the system and removes all fluid to the waste reservoir to reset for the next sampling and detection cycle;
(iii) a power source in operative connection to the electrodes, pump, and actuators;
and
(iv) a programmable microprocessor in operative connection to the electrodes, pump and actuators and including data storage for data from the detector.

18 more elements

A method of monitoring of soil or water nutrients in fields comprising:

(a) collecting soil water/air in situ into a porous tube placed at a selected depth in a field;
(b) pulling the collected soil water/air to an ion-selective detector comprising an ion-selective membrane at a working electrode comprising a sandwiched conducting layer, an ion-selective membrane, and an ion-to-electron transducing layer of a polymeric composite integrated with MoS2 between the ion-selective membrane and the conducting layer;
(c) passing the collected soil water/air by the ion-to-electron transfer layer of the polymeric composite integrated with MoS2 between the ion-selective membrane and the conducting layer of the working electrode to increase interfacial conductivity and minimize or prevent formation of an aqueous layer;
(d) passing the collected soil water/air by a reference electrode comprising a sandwiched conducting bottom layer, a middle layer with saturated chloride, and a protective top layer, to reduce chloride leaching-induced signal drift at the reference electrode;
(e) supplying electrical power to the electrochemical detector subsystem for ion-selective electrochemical detection related to the ion-selective membrane;
and
(f) storing data regarding the detection.

4 more elements

A system for self-contained, long term monitoring of chemicals in fields comprising:

(a) a soil sampling head, the sampling head comprising:
(i) a tube having at least a portion of its sidewall between opposite open ends which is gas/fluid permeable;
(ii) fluid connectors sealed at the opposite open ends of the tube;
(iii) the tube and connectors adapted to be placed in situ into soil or water at a measuring depth;
(b) a ruggedized housing including:
(i) a biochemical detection subsystem comprising:
(1) a sealed detection cell;
(2) at least one electrochemical sensor in the detection cell;
(ii) a fluid manipulation subsystem comprising:
(1) a soil water extraction and delivery fluid circuit comprising:
a. a vacuum pump in fluid communication with the detection cell;
b. a fluid conduit from a connector at one end of the tube in the soil water sampling head to the detection cell in the housing;
c. wherein selective operation of the vacuum pump during a sampling and detection cycle promotes collection of soil water/air in the soil sampling head and flow to the detection cell for chemical sensing through the said connector at one end of the tube;
(2) a system reset/reconditioning/recalibrating fluid circuit comprising:
(a) a cleaning liquid reservoir and actuator to move cleaning fluid to the detection cell;
(b) a waste liquid reservoir and actuator to move fluid in the tube to the waste liquid reservoir;
(c) a recalibration liquid reservoir and actuators to move fluid to the detection cell and the waste liquid reservoir;
(d) wherein selective operation of the actuators during a cleaning/reset/reconditioning cycle moves cleaning fluid through the system and removes all fluid to the waste reservoir to reset for the next sampling and detection cycle;
(iii) a power source in operative connection to the electrodes, pump, and actuators;
and
(iv) a programmable microprocessor in operative connection to the electrodes, pump and actuators and including data storage for data from the detector.

18 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/663,116Filed 24 Oct 2019 · us provisional application
Priority: 25 Oct 2018
Granted: 5 Jul 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

G01N 27/3335
Ion-selective electrodes or membranes: the membrane containing at least one organic component
B08B 9/0321
By the mechanical action of a moving fluid, e.g. by flushing: using pressurised, pulsating or purging fluid
G01N 1/02
Sampling; Preparing specimens for investigation: devices for withdrawing samples
G01N 27/327
Electrodes, e.g. test electrodes; Half-cells: biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements