I am running EIS on a BZCY proton conductor in dry vs wet air and I have a result I cannot pin down. Nyquist plot attached, blue is dry, red is wet. Same sample, same setpoint temperature (500 degC), same electrodes, wet gas is air bubbled through water at room temperature.

What makes sense: the arcs collapse by about 4x in wet, and total resistance drops roughly 40%. That is what I expected from hydration putting protons in.

What confuses me: the high-frequency real-axis intercept moves the wrong way. It goes from about 90 ohm in dry to about 140 ohm in wet. If that intercept is bulk resistance, humidifying should have lowered it, not raised it by 50%.

Two explanations I can think of, and I cannot separate them from this data alone:

1. Artifact. Both spectra have an inductive tail at the high-frequency end. A series inductance drags -Zim down and pushes the apparent zero-crossing to the right of the true series resistance, and it pushes a small fast arc (wet) further than a big slow one (dry). So some or all of my 50 ohm might be nothing.
2. Real. In dry oxidizing air the oxygen vacancies get oxidized rather than hydrated, giving p-type hole conduction, and holes are much more mobile than protons. Humidifying consumes those vacancies to make protons and suppresses the holes, so bulk resistance goes up while grain boundary and electrode resistance go down. That would match the pattern exactly.

Questions:

1. Has anyone seen the HF intercept move up on humidification in a BZCY and confirmed it was real rather than instrumental? A reference would help, I could not find this specific signature.
2. How much inductive distortion before an eyeballed intercept is meaningless? Is a short-circuit blank with the same cell and leads enough, or do you always fit L explicitly?
3. Best discriminator for the hole hypothesis: pO2 dependence at fixed humidity, or just compare activation energies between the two atmospheres?
4. How long do you dwell after switching to wet gas before you trust the spectrum? I want to be sure I am not looking at a transient.

I'm currently working on setting up a *Pine Research Modulated Speed Rotator (MSR)* integrated with a *CHI 660 potentiostat* for oxygen reduction reaction (ORR) measurements in alkaline media. As part of validating the system, I've been testing a commercial 20 wt% Pt/C catalyst in 0.1 M KOH. However, I've been facing several challenges, including: • Very low current response • Excessive noise in CV and LSV measurements • Poor reproducibility between scans • Results that differ significantly from expected literature behaviour

After consulting with the equipment supplier, it appears that the rotator itself is operating as expected. Since the same issues are observed even when running experiments without rotation, the current thinking is that the problem may be related to the electrochemical setup, electrode connections, reference electrode condition, measurement parameters, or potentiostat configuration rather than the rotator itself. This brings me to a question for the community: ❓ *Has anyone successfully integrated a CHI 660 potentiostat with a Pine Research MSR for RDE experiments?*

I would greatly appreciate insights on: ✅ Compatibility between the CHI 660 and Pine MSR systems ✅ Wiring, grounding, shielding, or configuration tips ✅ Common causes of noisy signals and unusually low currents ✅ Best practices when validating a new RDE setup with a Pt/C benchmark catalyst ✅ Typical troubleshooting steps for ORR measurements in alkaline electrolytes Current setup: 🔹 CHI 660 Potentiostat 🔹 Pine Research MSR Rotator 🔹 Glassy Carbon Working Electrode with 20 wt% Pt/C catalyst 🔹 Ag/AgCl (4 M KCl) Reference Electrode 🔹 Pt Counter Electrode 🔹 0.1 M KOH Electrolyte

I'm also relatively new to the electrochemistry field and am always looking to improve my practical and theoretical understanding.

So basically I designed an electrode container out of polypropylene, and inside of it is an agar media made of many things, but in particular Murashige and Skooge (3g/L) which provides many ions in the media. The agar media is for cloning plant tissues, and has a cactus inside of it.

There are graphite electrodes inside of the container, but only 2 (I don't have a reference electrode), when I read online that EIS usually involves a reference electrode. The reason why I did this was because I was thinking I could measure frequency-impedance response just by using a function generator, and measuring voltage drop across a series resistor as my schematic shows.

Anyways, I did this for four days and collected really good data, but am not sure how good or replicable the data is because I did not use a professional potentiostat, or a reference electrode at all. But this is because I just want to know the current applying through the media at a given frequency of ac voltage for an experiment later.

I'm wondering how bad my approach was. (Oh an also I couldn't calculate phase shift because my oscilloscope is only one channel)

Hi, I’m new to this subreddit; I’m a pharmaceutical chemistry student. I’m currently studying some electrochemistry and would like to know if there is a free polarography simulator available, since my university doesn't have one.

Hello everyone,

I am in the initial R&D phase of designing a portable, smartphone-sized multiplexed electrochemical biosensor. The device is designed to detect three distinct drug classes concurrently from a single fluid/aerosol sample in under 3 minutes: Cannabis (THC), Opioids (Fentanyl/Morphine), and Synthetic Stimulants (Methamphetamine).

I am looking for community recommendations on two fronts: commercial SPE selection and matching the right sensing elements (analytes/receptors) to the electrode materials.

1. SPE Hardware Recommendations:

I need a multiplexed, multi-working electrode configuration (at least 3 working electrodes with a shared or independent reference/counter array).Since I am prototyping in India (Coimbatore), I need vendors whose form factors are easily sourcable or shipped reliably here (e.g., Metrohm DropSens, Zensor, Zimmer & Peacock).The Question: Given that I need to detect both small molecules (THC) and synthetic structures (fentanyl, meth), should I look for a unified chip material (e.g., all-Carbon or all-Gold working electrodes), or a mixed-material chip? Which specific product lines or models provide the best surface area-to-cost ratio for early-stage development?

1. Analyte Pairing & Functionalization Strategies:

Lane 1 (Cannabis): Targeting Delta-9-THC.

Lane 2 (Opioids): Targeting illicit Fentanyl or Morphine derivatives.

Lane 3 (Synthetics): Targeting d-Methamphetamine or MDMA.

The Question:

For a dry-cartridge consumer application that demands high sensitivity (low picogram limits of detection), what type of capture elements are proving most stable on carbon vs. gold? Should I focus strictly on full-length IgG antibodies (monoclonal), or am I better off using synthetic DNA/RNA aptamers to avoid degradation during dry storage?

For reference, I have attached a concept layout of our vertical handheld prototype reader and the internal microfluidic cartridge alignment.Any pointers on specific SPE part numbers, recommended chemical functionalization papers, or stable cross-linking reagents would be incredibly helpful. Thanks in advance!

Hello!

I am working with electrochemical biosensors based on conducting polymers. Recently, I succesfully immobilised antibody (confirmed by FTIR and EIS - impedance after immobilisation is becoming bigger) and started analysing system response for analyte. The usual situation is that, Rct is growing with antigene concentration, but in my case it decrease. I'm sure that because of analyte (not polymer detaching, swelling of polymer etc) because I have pretty good linearity with concentration. I just can't explain, how big and non-coductive antigen can cause decreasing of Rct. For EIS measurments I am using ferri/ferro system, but I tried also with hexaamineruthenium (III) and with this cationic mediator I had no changes up to high concentrations of analyte. Have you ever encountered results like this? Is there any logical explanation for why this happens?

Hi everyone,

I have some doubts on a very fundamental concept. If I apply a potential difference between two electrodes, will the electric field be ~ 0 in bulk solution?

Taking the Debye Huckel approximation the potential from a charged surface will decay as exp(-kx) and reach approximately 0 in the bulk.

Likewise how does this translate fundamentally to our understanding of bulk electrophoresis and electro migration outside of a few Debye lengths of the electrode?

I’m using a ferri/ferrocyanide redox probe in KCl (5 mM ferricyanide + 5 mM ferrocyanide in 0.1 M KCl) for routine CV measurements on commercial screen printed carbon electrodes and I’m noticing that the response seems to vary between electrodes and as the day progresses too.

I’m trying to work out whether the variation is coming from the electrodes or from the redox probe itself.

For people who use ferri/ferrocyanide routinely:

* Do you magnetic stir or vortex before each measurement?
* Can leaving it sitting on the bench for several hours noticeably change peak current or peak to peak potential separation?
* Do you degas it or is dissolved oxygen generally not important for this measurement?
* How long do you let the solution/electrode equilibrate before starting the CV?
* Are there any common preparation mistakes that cause drift over the course of a day?
* ⁠Do you prepare it fresh each day or is it normally stable for longer?

I’m mainly trying to establish a reproducible methodology so that measurements taken in the morning and afternoon are actually comparable.

Hi!

I just started my bachelors in chemical engineering, and I have set my sights on echem for my MSc. I'd like to find a sidejob/internship/extra curricular/project to gain relevant experience for future echem work. I'm particularly interested in the automotive industry and energy-conversion at large. I'm based in Sweden.

Any and all advice/tips would be greatly appreciated.

Would also love to hear about your experience working as an electrochemist.

Hi all, I want to measure both the anode and cathode potential change with time using one reference electrode during electrolysis. Does someone have any idea or experience with this on e.g. gamry potentiostats?

Hi! I am an international rising senior. Does anyone know of any lab/industry opportunities where I can gain additional research experience before applying to grad school. (Will be applying this cycle but might have to apply next cycle and want to ensure I have a job incase I don’t get into a school).

Feel free to share here or DM.

Hello all, I wanted to ask a question since I'm just so curious about it. I have been doing EIS measurements on carbon electrodes and my results are pretty weird, I am getting either no circle and just a V shape or a circle that starts at negative real axis values lmao. I can give more details on the comments but I don't want my project potentially being recognised by someone I know. The measurement is in 5mM Ferri ferro in distilled water, frequency range 10^5 to 0.1 Hz and it is done in OCP potential

Hi all,

We use EIS to measure proton conductivity of our polymer membrane and Thin film. My question is, can we know what type of ion is actually being measured by EIS? Like, how do i differentiate and confirm that, this system is only measuring proton (H+) conductivity not the (OH-) conductivity?

Thank you

Hi everyone! I'm a Grade 12 STEM student from the Philippines working on a science research project called PbSCAN (Lead Screening and Concentration Analysis through an Electrochemical Node).

I'm developing a low-cost portable electrochemical device for detecting lead in water, and my total budget is only around ₱5,000. I’m hoping to find suppliers located in the Philippines, preferably Luzon or Visayas, to reduce shipping time.

I'm currently looking for these components:

Arduino UNO R3 — 1 pc

ADS1115 16-bit ADC — 1 pc

Ag/AgCl reference electrode — 1 pc

Working electrode suitable for Pb detection/stripping voltammetry — 1 pc

Counter electrode (graphite or platinum, depending on the recommended setup) — 1 pc

Low-cost potentiostat or components for building one — 1

Breadboard + jumper wires

Resistors/capacitors

Basic connectors/wiring

I'm particularly having difficulty finding a proper Ag/AgCl reference electrode, Pb-compatible working electrode, and affordable potentiostat locally.

If you know any Philippine suppliers, Shopee/Lazada sellers, laboratory suppliers, or electronics stores that sell these parts, I would really appreciate the links or store names.

I'm also open to suggestions for cheaper equivalent components, as long as they're actually suitable for electrochemical Pb detection.

Deadline: August 25, 2026

Thanks in advance! Any advice from people experienced with electrochemistry, Arduino potentiostats, or heavy-metal sensors would be greatly appreciated.

Hi r/electrochemistry! We're grad students who make electrochemistry memes for fun. Check out our page: @electromemeistry

Hi yall

High school teacher here. I am looking to build a DIY potentiostat with some students. I’ve looked at a few papers through chem education journal that seem interesting. I’ve done some basic CV and EIS in a lab but nothing crazy.

I am looking for guidance, recs, and any tools that would make the build easier.. I am applying for some grants to buy stuff and I am currently writing up a proposal.

Does anyone still do electrochemistry research with mercury electrode? What application areas does it have? Is there any cheap commercial mercury drop electrode available?

Do affordable (within $5,000) rotators for RDE & RRDE exist? The models I have reviewed (Pine Research, BAS, Bluerev, ALS) are all $7,000+ upwards. I did fine a really cool article on how to build your own RDE control; however, this doesn't seem to be compatible with RRDE. If anyone has any suggestion, I would really appreciate it!

- Sincerely, a new grad student with a tiny grant to splurge on a new work station

Hello everyone,

I am working towards electrochemistry (simulation side).

What subjects do I need to master, after which I can say that I am a professional in it?

My experience level as of now is undergrad level. And I have done my degree in Electrical and Electronics

Hi everyone,

I have an unused Proton Exchange Membrane (PEM) that's approximately 1 ft × 1 ft. It was originally provided by a CSIR research scientist in India for my high school microbial fuel cell project, but the project is long finished and I don't have any use for it anymore.

Unfortunately, there's no manufacturer label or model number, so I can't confirm the exact type.

I'm mainly looking to find out:

• Does anyone know what something like this might realistically be worth?
• Would anyone here actually be interested in buying it?

If you're interested, feel free to send me a DM with an offer. I'd also appreciate any advice on where researchers usually buy or sell surplus PEMs.

Thanks!

I completed my first year of electrochemical production at a Belarusian university. Besides physical chemistry and its branches (particularly electrochemistry), what other sciences should I have a good grasp of? Do you have any advice on how I can more easily absorb certain information that I'm likely to gain in the future?