ION-01X – Amplifier for Ion-Sensitive Electrodes

Main Advantages of the ION-01X Amplifier

• Record the smallest ion-currents
• Reference electrode with high common mode rejection
• Capacitance compensation for electrode and reference
• Also available as module for the EPMS-07 system

The ION-01X is a high-sensitivity amplifier designed for measuring the very small electrical signals generated by ion-selective electrodes (ISEs). It is intended for potentiometric measurements in which the electrode potential varies with the activity of a target ion in the sample. The amplifier provides a high-impedance, low-bias-current interface to the sensing and reference electrodes, minimizing loading of the electrode and allowing accurate measurement of high-impedance ion-sensitive sensors. According to NPI Electronic, the ION-01X features an input impedance above 10 TΩ, an input bias current below 150 fA, differential common-mode rejection greater than 120 dB at a gain of 100, selectable ×10/×100 gain, and adjustable offset and capacitance compensation.

The measurement is based on the potentiometric principle: the ion-selective membrane develops an electrochemical potential that depends approximately logarithmically on the activity of the target ion, according to the Nernst relationship. The ION-01X measures the voltage difference between the sensing electrode (SENSE) and a stable reference electrode (REF) while drawing virtually no current. Its differential input stage, high common-mode rejection, low-pass filtering, and capacitance compensation help suppress interference and maintain signal integrity, while the built-in electrode-resistance test can be used to verify the condition of both sensing and reference electrodes. The amplified signal is provided at the output for further recording or analysis.

Features:

• Differential input: cmr >120 dB @ gain 100
• Input impedance: >100 TΩ; ultra-low BIAS current <150 fA
• Input voltage range: 1000 mV DC
• Inputs with small headstage, Teflon isolated connector
• Integrated electrode holder
• OFFSET compensation for both inputs; range: ±100 mV
• C.COMP. for both inputs; range: 0 – 30 pF
• Low-pass filter for REF and SENSE input to improve AC cmr (common mode rejection)
• Output gain: x10 or x100; range: ±12 V
• Digital display: XXX.X mV
• Electrode resistance test : XXX.X MΩ or XX.XX GΩ
• Built-in ramp generator: 1.5 V / s., external signal input available