GAS/VAPOR and LIQUID FLOW CELLS

Flow Cell Schematic Exploded View

Flow Cell Schematic Compact View

Flow Cell Products	Line and Space, Digit Length	Designs	Conductor
Liquid Flow Cell Detector (FCD)
FCD 1010.3-FD Flow Cell Detector	10 microns, 3 mm long	10 bands	Au, Pt
IME 1010.3-FD-Au or Pt Flow Cell Sensor (refill sensor for Flow Cell Detector, FCD)	10 microns, 3 mm long	10 bands	Au, Pt
Controlled Environment Cell (CEC)
CEC 1010.3-FD Controlled Environment Cell	10 microns, 3 mm long	10 bands	Au, Pt
IME 1010.3-FD-Au or Pt Flow Cell Sensor (refill sensor chip for Controlled Environment Cell, CEC)	10 microns, 3 mm long	10 bands	Au, Pt
CEC 1050.5-FD Controlled Environment Cell	10 microns, 5 mm long	50 bands	Au, Pt
IME 1050.5-FD-Au or Pt Flow Cell Sensor (refill sensor chip for Controlled Environment Cell, CEC)	10 microns, 5 mm long	50 bands	Au, Pt

Introduction and Background

Applications of FCDs and CECs

Technical Specifications

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Price List

Methods

Application Notes

Introduction and Background Ø The Controlled Environment Cell is used in the development of electronic noses, the study of polymer-vapor interactions by impedance and dielectric spectroscopies, and as a volatile organic compound (VOC) sensor. The Controlled Environment Cell is used for performing AC electrical impedance and DC conductance experiments under controlled gas/vapor environment conditions. The design is similar to that used in the laboratory of Prof. Mark Wrighton to study the electrical impedance changes in electropolymerized polyaniline films upon exposure to varying humidities. This design has also been used by scientists at ICI Chemicals to study acid-base interactions (by electrical impedance spectroscopy (0.1 mHz - 60 KHz)) of various probe vapors (water, acetone, chloroform, methanol) with ultra thin polymer coatings. Ø The Liquid Flow Cell Detector (FCD) is used as an electrochemical detector (ECD) in Liquid Chromatography (LC) and Flow Injection Analysis (FIA) applications. The interdigitated electrode format of the flow cell sensor chip allows use of the ECD in amperometric generator-collector mode or electrochemical impedance mode. Both modes offer very high selectivity based on the redox properties of the analyte to be measured and very high sensitivity -- down to picogram levels for its limit of detection. A wide variety of ionic and non-ionic compounds may be readily detected by ECD, thus making ECD a highly versatile detection technique. Similarly, conductance detection is integral to Ion Chromatography (IC) and Flow Injection Analysis (FIA) where conductance changes in the range from 0.1 S to 10 mS may be readily measured usiung the Flow Cell Detector. Back to top Applications of FCDs Applications of the FCD in research and product development include: Electrochemical detection may be used in ultra-trace level biochemical analyses, in the analysis of various pharmaceutical compounds, in the detection and monitoring of environmental pollutants, and in "at-line" chemical and biological process monitoring. Conductance measurements may be used in Ion Chromatography. The IME 1010.3 FD LC sensor is also used in materials science research of electroactive polymer films. Polymer films that are spun cast, electropolymerized, or coated onto the LC sensor may be analyzed by AC Impedance, DC pulse amperometry, or by using the EPSIS (The Electroactive Polymer Sensor Interrogation System) in a flowing stream. Changes in electrical impedance or conductivity of the film could then be monitored in response to various ionic analytes, or redox active analytes. A further facility provided by the IME 1010.3 FD LC is the relative ease with which the sensor may be chemically modified and functionalized for the specific attachment or immobilization of bioactive molecules. The digits may be modified by platinization, amalgam formation, alkane thiols, or by electropolymerization of electroactive polymers. The interdigit space may likewise be modified using well established silane chemistries and derivatized by immobilized enzyme, antibodies, or enzyme-linked antibodies. The IME 1010.3 FD LC Sensor from ABTECH Scientific, is one more innovation in the application of combined electrochemical detection and conductance measurement to analytical problems in science and industry. The precisely microfabricated digits of gold or platinum replaces the familiar carbon paste and bulk metal disc electrodes in LC detection. Interrogation Methods The IME 1010.3 FD LC sensor may be operated by Pulsed Amperometry or Cyclic Voltammetry. In addition, the very close electrode separation (10 m.) and the long centerline meander length (ca. 57 cm) allows the use of AC Impedance and Discontinuous Small Amplitude Pulse (EPSIS) analytical methodologies. Back to top Technical Specifications Four (4) separate working electrodes are microfabricated on the single LC Sensor Chip. These working electrodes are combined into two (one pair of electrodes each) interdigitated microsensor array electrodes (IMEs or IDAs). Each IME pair consists of 10 opposing digits (lines) with each digit being 10 m wide and 2,990 m long. Opposing digits are separated by a 10 m space. This produces a centerline or serpentine length that is ca. 57 cm long.
	Ø Chip Substrate:	Schott D263 Borosilicate Glass
		Dielectric Constant, Epsilon(r) at 1 MHz		6.7
		Dielectric Loss Angle, tan delta, at 1 MHz		61 x 10-4
		Electrical Resistivity (50 Hz) (250 C)		1.6 x 108 ohm cm
		Coefficient of Linear Thermal Expansion, * 20-300 Deg C		7.2 x 10^-6 K^-1
		Refractive Index at 20 C, ne ( Lambda = 546.1 nm)		1.5249
	Ø Metallization:	100 Å Ti|W / 1000 Å Au or Pt and ITO = 10 Ohms/sq
	Ø IME SENSOR			1010.3	1050.5
			Digit length, d, (microns)	2990	4990
			No. of digit pairs per sensor, N	10	50
			Digit Width, a, (microns)	10	10
			Interdigit Space, a, (microns)	10	10
			Spatial Periodicity, l lambda, (microns)	40	40
			Zaretsky Meander Length, M, (cm)	2.99	24.95
			Center Line or Serpentine Length (cm)	5.72	49.6
			Cell Constant (cm-1)	0.33	0.04
			Electrode Area; each bus (cm-2)	3.03 x 10-3	2.50 x10-2
			Total Electrode Area; all busses (cm-2)	1.21 x10-2	9.98 x10-2
			Ø IME Chip Dimensions (l x w x t cm)
			Un-packaged Die	3.10 x 1.00 x 0.05 cm	2.00 x 1.00 x 0.05 cm
			Packaged Die	4.20 x 1.25 x 0.55 cm	3.10 x 1.25 x 0.55 cm
	Ø Packaging
	Electrode Body:		PVC-Jacketed printed circuit board
	Encapsulant:		Epoxy header. Silicon nitride packaged chip.
	Leadwires:		Gold plated pins
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Methods Ø Films or coatings may be applied to the IME device by dip coating, spin casting, spray painting, air-brushing, brush painting, by Langmuir-Blodgett thin film deposition technique, by electropolymerization, and by molecular self assembly. Back to top Application Notes For further information, request Application Notes or you may download application note files: Back to top

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Last Revision 09/09/2004. © 2000-2004 ABTECH Scientific, Inc.

Contact: Ann M. Wilson, Manager,
Applications Development ABTECH Scientific, Inc.
911 East Leigh Street G24, Richmond, Virginia 23219
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