Biosensors Selection Guide: World Precision Instruments

Download a PDF version of the Biosensor Specifications Sheet here.

WPI offers a range of biosensors for monitoring nitric oxide, hydrogen peroxide, oxygen and hydrogen sulfide. Specifications for these sensors are detailed below.

The macrosensors are 2mm "wet" sensors. These sensors are installed in a metal "sleeve" that looks like a tiny soda straw.The sleeve has a gas permeable membrane at the tip, and it is filled with an electrolyte. When it is immersed in a solution, the gas in solution (for example, nitric oxide) diffuses through the membrane, and the sensor measures it.
The microsensors are "dry" sensors. Most microsensors monitor nitric oxide, and there is also a hydrogen peroxide microsensor available.

Macrosensors (2mm)

WPI's 2mm macrosensors are uniquely designed with an internal reference electrode. These sensors are designed for use with the TBR1025, or TBR4100. The ISO-OXY-2 and the OXELP sensors have the same specifications. However, they have different connectors, because the OXELP is designed for use with the ISO2 dissolved oxygen meter.

NOTE: The sensitivity of WPI sensors varies with length and diameter. Each sensor is unique and will come with its own Sensor Performance Evaluation sheet. WPI sensors typically conform to the specifications offered in this article. Custom sensors, of course, will have unique tolerances and sensitivities.

	ISO-NOP	ISO-HPO-2	ISO-OXY-2 OXELP	ISO-H2S-2
Species	Nitric Oxide	Hydrogen peroxide	Oxygen	Hydrogen Sulfide
Outside Diameter	2mm	2mm	2mm	2mm
Response Time	< 5 sec.	<5 sec.	<10 sec.	<5 sec.
Lowest Detection Limit/Range	1nM	<100nM	0.1%	<5nM
Upper Detection Limit/Range	80µM (beyond 80µM, sensor accuracy is not guaranteed)	100µM	100%	100µM
Nominal Sensitivity-New Sensor	≤2pA/nM	8pA/μM	0.3-0.6nA/%	2pA/nM
Interferent (Selectivity Coefficient)	NaNO2 (10-6 or better)
Baseline Drift	<1pA/min	0.1pA/min.	<1%/min.	0.1pA/min.
Poise Voltage	865mV	400mV	-700mV	150mV
Typical Quiescent Baseline Current, 25ºC	3,000pA	850pA	15-40nA	15nA
Acceptable Baseline Range	1,000-8,000 pA	20-4,000pA	15-40nA	2.5-75nA
Typical Polarization Time	12+ hrs	2+ hours	1+ hours, 95%	12+ hours
Recommended Polarization Solution	0.1M KI/H2SO4	0.1M PBS	0.1M PBS	0.1M PBS
Temperature Dependent	Yes	Yes	Yes	Yes
Physiological Interference	None	None	None	None

Microsensors

	NOPF200	NOPF200-LXX	NOPF100 NOPF100-L	NOP70-LXX	NOPF500-Cxx	NOP3005	NOP3020	NOP30-L	NOP007	NOPNM	HPO-100	H2S-100
Species	Nitric Oxide										H₂0₂	H₂S
Outside Diameter (µm)	200	200	100	70	500	30	30	30	7	Conical tip:100nm Fiber: 7µm	100	100
Available Length² (mm)	1-5¹	1-10¹	1-5¹	3	5-10	0.5	2	3	2	2	1-4¹	1-5¹
Response Time (sec.)	< 5	< 5	< 5	< 3	< 3<10	<3	< 3	< 3	< 3	< 3	< 5	~5
Lowest Detection Limit/Range (nM)	0.2	0.2	0.2	1	10.2	1	1	1	0.5	0.5	< 10	<5
Nominal Sensitivity-New Sensor²(pA/nM)	≥20	≥50	≥10	≥10	≥20	≥1	≥1.5	≥1	≥1	≥0.5	≥1	1-4
Baseline Drift (pA/min)	none	none	none	none	none	none	none	none	none	none	<2.0	<2
Poise Voltage (mV)	865	865	865	865	865	865	865	865	865	865	400	150
Typical Quiescent Base-line Current, 25ºC (pA)	2500	3500	2000	3500	5000	1000	500	500	300	300	<1000	1000
Acceptable Baseline Range (pA)	500-8000	500-8000	500-8000	2000-6000	3000-25000	150-3500	500-5000	20-6500	200-1500	50-100	150- 1200	100-2000
Typical Polarization Time (hrs)	2+	8+	2+	2+	8+	1+	1+	1+	1+	1+	1+	4+