Pulsed Current Anion Sensor Data for Multiple Nonspecific Ion Selective Electrodes - Individual Ion Responses

Dataset Overview

This dataset contains time-resolved electrochemical and pH-related measurements from polymer-coated polypyrrole (PPy) sensing electrodes evaluated across multiple anions, concentrations, and pulse-current settings. The data are provided in long-format Parquet for scalable analysis and plotting.

Experimental Setup and Fabrication Summary

An AT-cut, 5 MHz, gold-coated quartz crystal (Phillip Technologies) mounted on a QCM-200 controller (Stanford Research Systems) was used as the substrate. PPy was electrodeposited onto the gold surface at 0.8 V vs. Ag/AgCl for 2 minutes in aqueous solution containing 0.1 M pyrrole and 0.1 M sodium nitrate under continuous UHP argon purge. After deposition, films were rinsed with methanol and dried at 50 C for 10 minutes.

A polymer-screening workflow was used to identify stable, spin-coatable nonspecific coatings. Candidate polymers were evaluated for solvent compatibility, film formation, and aqueous stability. PAN, PVA, and PVC were down-selected for continued testing (using DMF, methanol, and DMSO, respectively) based on solubility, coating quality, and stability in aqueous conditions.

Polymer coatings were prepared at 1 mg/mL and spin-coated onto PPy-coated quartz using 150 uL per substrate with a two-step spin program (1000 rpm for 40 s, then 3000 rpm for 10 s), followed by acetone rinse and argon drying.

Electrochemical Measurement Summary

Electrochemical response was measured for seven anions:

• nitrate (NO3-)
• chloride (Cl-)
• perchlorate (ClO4-)
• sulfate (SO4^2-)
• bromide (Br-)
• carbonate (CO3^2-)
• hydrogen phosphate (HPO4^2-)

Each anion was tested at 10^-1 M, 10^-3 M, and 10^-5 M.

Pulse-current measurements used a two-step sequence at each current setting:

• anodic pulse (10 s) to measure overpotential response vs. OCV
• cathodic pulse (10 s) to discharge/reset the PPy layer

Ten current levels were tested from 0.1 uA to 100 uA.

The overall campaign design comprised 21 measurement sets, tested across three electrode types with triplicate electrodes, yielding 1,890 individual pulse-current runs.

Data Utility

The dataset supports:

• direct plotting of potential-time and pH-related traces;
• comparison across polymer type, ion identity, concentration, and current step;
• replicate-aware aggregation and statistics;
• quality control at the source-file grouping level without exposing internal filenames.

Data Organization

• Format: Parquet (columnar)
• Rows: 16,386,405
• Columns: 34
• Row unit: one recorded timepoint from one measurement-file segment

Key analysis dimensions:

• Polymer Name, Electrode Name
• concentration fields Ca-Cg
• step_index, step_type
• anonymized provenance flags run_id and file_id

Core signal/time fields include:

• time/s, control/mA, I/mA
• Ewe/V, <Ewe>/V
• Analog IN 1/V, pH_signal_V
• charge, capacitance, and energy derived columns

Public Provenance Model

To preserve analytical grouping while removing sensitive path metadata, direct source columns were excluded from this public file and replaced by deterministic anonymized flags:

• run_id: experiment-level grouping identifier
• file_id: source-file-level grouping identifier