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This is oddly specific, but I am having trouble making the setup work for my electrochemical cell. We're doing Scanning Electrochemical Cell Microscopy (SECCM)* and the device has a capillary tube fit through a small hole, where the electrolyte droplet makes contact with the metal surface. Here's the issue - the hole is so snug that the capillary tube is prone to breaking inside of it, which leaves behind tiny glass shards and makes it unable to fit. I have been trying for nearly a day to dislodge this one invisible piece that makes it impossible to fit another tube through.

I have tried several options including rinsing out the hole with water, getting an equal diameter PTFE tube to try pushing through (it also gets stuck), and blowing nitrogen gas through, but none of them have worked so far. Would trying to vacuum likely be more successful than blowing? I think I'm seeing tiny pieces of glass accumulate on my benchtop, so it might be that what I'm trying is working, but just takes a lot of perseverance, in which case it doesn't feel like a practical solution moving forward.

Thanks so much for any input!

* As an illustration of the technique, see e.g.,

Daviddi, E.; Gonos, K. L.; Colburn, A. W.; Bentley, C. L.; Unwin, P. R. Scanning Electrochemical Cell Microscopy (SECCM) Chronopotentiometry: Development and Applications in Electroanalysis and Electrocatalysis. Anal. Chem. 2019, 91, 9229–9237. doi.org/10.1021/acs.analchem.9b02091 (link to author's copy)

Bentley, C. L.; Kang, M.; Unwin, P. R. Scanning Electrochemical Cell Microscopy (SECCM) in Aprotic Solvents: Practical Considerations and Applications. Anal. Chem. 2020, 92, 11673–11680. doi 10.1021/acs.analchem.0c01540 (open access)

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  • $\begingroup$ Please explain ! What is the meaning of SECCM ? What and where are the electrodes ? What is the composition of the electrolytes ? Why do yo need nitrogen ? $\endgroup$
    – Maurice
    Commented Jun 21 at 20:28
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    $\begingroup$ It would help if you were more specific about the hole and capillary size (10 µm? 1 µm?), and the material of the substrate. If the metal can withstand it, clean with an ultrasonic bath to dislodge the glass, or use warm, strong NaOH solution in an ultrasonic bath (under a hood, while wearing face protection and gloves!) to dissolve the glass. $\endgroup$
    – DrMoishe Pippik
    Commented Jun 21 at 21:13
  • $\begingroup$ @rydo To be more meaningful for subscribers to chemistry.se, I expanded the abbreviation you used. $\endgroup$
    – Buttonwood
    Commented Jun 22 at 11:37
  • $\begingroup$ @Maurice This part of the question possibly was addressed: a sitting drop electrode (though not with Hg...) gliding over a sample, coupled with the resolution of an AFM (example). Perhaps such tips (with capillaries mounted) are commercially available, too? $\endgroup$
    – Buttonwood
    Commented Jun 22 at 11:39
  • $\begingroup$ If it were not for a capillary with an open diameter in µm scale (as mentioned in DrMoishe Pippik's comment, or the publications tentatively added), but a glass capillary made from a finer Pasteur pipette with (mechanical) fragile walls: could one i) keep an almost fitting fine glass/wire in the capillary (similar to a lead in a mechanical pencil) while passing the capillary through the holder? Once in place, ii) the inner lead -- no longer needed for mechanical stability -- then could be retracted. $\endgroup$
    – Buttonwood
    Commented Jun 22 at 11:55

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It would be helpful with more specifications,yet here I am stating wider range of methods.

1.Here we would need a vacuum suction device else a powerful vacuum cleaner with a narrow nozzle attachment would do the job.

Now, place the nozzle close to the hole (make sure it does not obstruct the capillary tube) and turn on the vacuum. This suction might help to clear and remove the glass shards through the hole.

2.For this method(The simplest),we need an ultrasonic cleaner and a solvent whose nature varies with respect to the nature of the materials out of which the capillaries and other structures are made( preferably acetone or ethanol).Use the cleaner to remove the glass shards.

3.This method is highly dangerous,perform with care.

SAFETY MEASURES: training Requirement: Proper handling of hydrofluoric acid (HF) necessitates formal training to ensure understanding of its properties and associated risks.

Protective Measures: Use of HF requires comprehensive personal protective equipment (PPE) to prevent exposure to skin and eyes.

Antidote Access: Availability of antidotal treatments such as calcium gluconate gel is essential in case of accidental exposure to HF.

Safety Protocol Review: It is advisable to review and reorder procedural methods to enhance safety and mitigate potential risks when working with HF.

We would need a strong acid like hydrofluoric acid (HF) or a fluoride-containing compound according to the material of the capillary tube and other structures.Now with significant care and safety soaking the obstructed part in a dilute solution of HF can dissolve the glass shards.

Hope these help.

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    $\begingroup$ I said in your other answer. Do not post new answer. Instead edit your old answer. $\endgroup$
    – Nilay Ghosh
    Commented Jun 23 at 6:01

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