The monitoring of toxic inorganic
gases and volatile organic compounds
has brought the development of field-deployable, sensitive, and scalable
sensors into focus. Here, we attempted to meet these requirements
by using concurrently microhole-structured meshes as (i) a membrane
for the gas diffusion extraction of an analyte from a donor sample
and (ii) an electrode for the sensitive electrochemical determination
of this target with the receptor electrolyte at rest. We used two
types of meshes with complementary benefits, i.e., Ni mesh fabricated
by robust, scalable, and well-established methods for manufacturing
specific designs and stainless steel wire mesh (SSWM), which is commercially
available at a low cost. The diffusion of gas (from a donor) was conducted
in headspace mode, thus minimizing issues related to mesh fouling.
When compared with the conventional polytetrafluoroethylene (PTFE)
membrane, both the meshes (40 μm hole diameter) led to a higher
amount of vapor collected into the electrolyte for subsequent detection.
This inedited fashion produced a kind of reverse diffusion of the
analyte dissolved into the electrolyte (receptor), i.e., from the
electrode to bulk, which further enabled highly sensitive analyses.
Using Ni mesh coated with Ni(OH)2 nanoparticles, the limit
of detection reached for ethanol was 24-fold lower than the data attained
by a platform with a PTFE membrane and placement of the electrode
into electrolyte bulk. This system was applied in the determination
of ethanol in complex samples related to the production of ethanol
biofuel. It is noteworthy that a simple equation fitted by machine
learning was able to provide accurate assays (accuracies from 97 to
102%) by overcoming matrix effect-related interferences on detection
performance. Furthermore, preliminary measurements demonstrated the
successful coating of the meshes with gold films as an alternative
raw electrode material and the monitoring of HCl utilizing Au-coated
SSWMs. These strategies extend the applicability of the platform that
may help to develop valuable volatile sensing solutions.