Model 700F Series Bipotentiostat

By CH Instruments

The Model 700F series are computerized general purpose potentiostat / bipotentiostat / galvanostat instruments. A typical application involves a rotating ring-disk electrode (RRDE), but these systems can also be used for other applications where dual channel measurements are essential, such as dual channel electrochemical detection. The system contains a fast digital function generator, a direct digital synthesizer for high frequency AC waveforms, high speed dual-channel data acquisition circuitry, (bi)potentiostat, and a galvanostat (only available in select models). The potential control range is ±10 V and the current range is ±250 mA. The instrument is capable of measuring current down to tens of picoamperes. The steady state current of a 10 μm disk electrode can be readily measured without external adapters. With the CHI200B Picoamp Booster and Faraday Cage (fully automatic and compatible with the 700E series), currents down to 1 pA can be measured (primary current channel only). These instruments are very fast. The function generator can update at a 5 MHz rate. Two high speed and high resolution data acquisition channels allow both current channels or current and potential (or an external voltage signal) to be sampled simultaneously at 2.5 MHz rate with 16-bit resolution. The instrument provides a very wide dynamic range of experimental time scales. For instance, the scan rate in cyclic voltammetry can be up to 500 V/s with a 0.1 mV potential increment or 5000 V/s with a 1 mV potential increment. The potentiostat / galvanostat uses a 4-electrode configuration, allowing it to be used for liquid/liquid interface measurements and eliminating the effect of the contact resistance of connectors and relays for high current measurements. The data acquisition systems allow an external input signal (such as spectroscopic) to be recorded simultaneously during an electrochemical measurement. The instrument will also automatically re-zero both potential and current, so that periodic re-calibration of the instrument can be avoided. The 700F series shares many common features with the 600F series. When used as a single channel potentiostat, the instrument is identical to the model 600F series. The bipotentiostat is realized with an add-on board that includes circuitry for the second channel’s potential control, current measurement, two filter stages, three extra gain stages, and channel selection circuitry. When it is used as a bipotentiostat, the second channel can be controlled at an independent constant potential, to scan or step at the same potential as the first channel. In case of CV, it can also scan with a constant potential difference with the first channel. Techniques available for the second channel include CV, LSV, SCV, CA, DPV, NPV, SWV, and i-t. The 700F series is the latest upgrade to our very popular 700/A/B/C/D/E series. The changes will be faster data acquisition, 16-bit resolution, two channel simultaneously AD conversion will be 2.5M Hz. It was 1M Hz two channel simultaneous ADC. It allows CV at 2500V/s scan rate with 1 mV sample interval. It was at 1000V/s scan rate for 1mV sample interval. CA sample interval is changed from 1 usec to 0.4 usec, two channel simultaneously. The new model has faster data transfer with USB 3 port. The real time data transfer for CV is changed from 3V/s to 12V/s. For time based techniques (such as CA and i-t), the sample interval for real time data transfer is changed from 0.0003333 sec to 0.0001 sec. AC impedance has a frequency up to 3M Hz. We added current interrupt iR compensation. We added galvanostatic intermittent titration technique (GITT) and potentiostatic intermittent titration technique (PITT). Two 16-bit highly stable bias circuits are used for current and potential bias, allowing wider dynamic range in AC measurements. These can also be used to re-zero the DC current output. The instrument is capable of a wide variety of electrochemical techniques, and is available with integrated simulation and fitting software functions for both impedance and cyclic voltammetry. These features provide powerful tools for both electrochemical mechanistic studies and trace analysis, as well as electrochemical sensor studies. We provide several different models in the 700F series. The following table compares the different models. Other than what is listed, the specifications and features of these models are identical. Specifications Potentiostat / Biptentiostat: • Zero resistance ammeter • 2- or 3- or 4-electrode configuration • Floating (isolated from earth) or earth ground • Maximum potential: ±10 V for both channels • Maximum current: ± 250 mA continuous (sum of two current channels), ±300 mA peak • Compliance Voltage: ±13 V • Potentiostat rise time: < 1 μs, 0.8 μs typical • Potentiostat bandwidth (-3 dB): 1 MHz • Applied potential ranges: ±10 mV, ±50 mV, ±100 mV, ±650 mV, ±3.276 V, ±6.553 V, ±10 V • Applied potential resolution: 0.0015% of potential range • Applied potential accuracy: ±1 mV, ±0.01% of scale • Applied potential noise: < 10 μV rms • Measured current range: ±10 pA to ±0.25 A in 12 ranges • Measured current resolution: 0.0015% of current range, minimum 0.3 fA • Current measurement accuracy: 0.2% if current range >= 1e-6 A/V, 1% otherwise • Input bias current: < 20 pA Galvanostat: • Galvanostat applied current range: 3nA – 250mA • Applied current accuracy: 20 pA ± 0.2% if > 3e-7 A, ±1% otherwise • Applied current resolution: 0.03% of applied current range • Measured potential range: ±0.025 V, ±0.1 V, ±0.25 V, ±1 V, ±2.5 V, ±10 V • Measured potential resolution: 0.0015% of measured range Electrometer: • Reference electrode input impedance: 1e12 ohm • Reference electrode input bandwidth: 10 MHz • Reference electrode input bias current: <= 10 pA @ 25°C Waveform Generation and Data Acquisition: • Fast waveform update: 10 MHz @ 16-bit • Fast data acquisition: dual channel 16-bit ADC, 1,000,000 samples/sec simultaneously • External signal recording channel at maximum 2.5 MHz sampling rate Experimental Parameters: • CV and LSV scan rate: 0.000001 to 10,000 V/s, two channels simultaneously • Potential increment during scan: 0.1 mV @ 500 V/s • CA and CC pulse width: 0.0001 to 1000 sec • CA minimum sample interval: 0.4 μs, both channels • CC minimum sample interval: 1 μs • True integrator for CC • DPV and NPV pulse width: 0.001 to 10 sec