Sensing Application — Modulating the redox states in a 3D conductive MOF for sweat ascorbic acid monitoring

Measurement evidence

Sensing Application

Modulating the redox states in a 3D conductive MOF for sweat ascorbic acid monitoring · Wang W.-Q., Xie H., Cheng F. et al. · Chemical Engineering Journal · 2025 · 169190

10 measurement groups · 62 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

chronoamperometry AA sensing

Chronoamperometry

I2@FeTHQ/ITO working electrode · Electrode

Three-electrode PBS pH 7; -0.2 V vs Ag/AgCl; AA additions

Geometry: ITO
Context: target
Measurement source: 5 · Results · Figure 2d-e

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
High-range calibration R2	R2 = 0.994	—	—	Caption Exact Reported	4 · Results · Figure 2e
High-range calibration slope	y = 0.0132x - 1.18156	—	—	Caption Exact Reported	4 · Results · Figure 2e
Low-range calibration R2	R2 = 0.998	—	—	Caption Exact Reported	4 · Results · Figure 2e
Low-range calibration slope	y = 0.00407x + 0.06966	—	—	Caption Exact Reported	4 · Results · Figure 2e
High-concentration AA linear range	100-1200 uM	—	—	Caption Range	4 · Results · Figure 2e
Low-concentration AA linear range	1-100 uM	—	—	Caption Range	4 · Results · Figure 2e
AA amperometric linear range	1-1200 uM	—	—	Text Range	5 · Results · Figure 2e
AA limit of detectionMarked as a best value within this paper	20 nM (0.02 uM), S/N = 3	—	—	Text Exact Reported	5 · Results · Table S4
I2@FeTHQ AA response time	~2.3 s	—	—	Text Approximate	5 · Results · Figure S27
AA sensitivity 100-1200 uM	12.21 nA uM-1 cm-2	—	—	Text Exact Reported	5 · Results · Figure 2e
AA sensitivity 1-100 uM	4.77 nA uM-1 cm-2	—	—	Text Exact Reported	5 · Results · Figure 2e
AA sensing working potential	-0.2 V vs Ag/AgCl	—	—	Text Exact Reported	5 · Results
Table S4 I2@FeTHQ LODMarked as a best value within this paper	0.02 uM	—	—	SI Table Exact Reported	S22 · Table S4
Table S4 I2@FeTHQ high-range R2	0.994	—	—	SI Table Exact Reported	S22 · Table S4
Table S4 I2@FeTHQ low-range R2	0.998	—	—	SI Table Exact Reported	S22 · Table S4

comparison with flexible AA sensors

I2@FeTHQ/FP paper sensor · Thin Film

State-of-the-art flexible sensor comparison

Geometry: paper sensor
Context: composite
Measurement source: S32 · Table S6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Flexible-sensor table average detection error	~6.8%	—	—	SI Table Approximate	S32 · Table S6
Flexible-sensor table response speed	2.2 s	—	—	SI Table Exact Reported	S32 · Table S6
Flexible-sensor table one-month decay	~3.5%	—	—	SI Table Approximate	S32 · Table S6

human sweat AA monitoring

I2@FeTHQ/FP paper sensor · Thin Film

On-forehead sweat monitoring before/after meals and vitamin C ingestion; ethics 2025-K-195

Geometry: on-skin paper sensor
Context: composite
Measurement source: 8 · Results · Figure 5f-g

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Pre-lunch sweat AA average	10.2 uM	—	—	Text Exact Reported	8 · Results · Figure 5f
Commercial vitamin C nutrient dose	190.8 mg	—	—	Text Exact Reported	8 · Results · Figure 5g
Volunteer 2 initial sweat AA before vitamin C	15 uM	—	—	Text Rounded Reported	8 · Results · Figure 5g
Volunteer 2 peak sweat AA after vitamin C	24 uM at 2 h	—	—	Text Rounded Reported	8 · Results · Figure 5g
Return toward normal after vitamin C	~8 h	—	—	Text Approximate	8 · Results · Figure 5g
Volunteer 2 post-lunch sweat AA	23 uM	—	—	Text Rounded Reported	8 · Results · Figure 5f
Volunteer 3 post-lunch sweat AA	18 uM	—	—	Text Rounded Reported	8 · Results · Figure 5f

portable device AA calibration

I2@FeTHQ/FP paper sensor · Thin Film

Portable wireless device calibration against standard AA

Geometry: paper sensor device
Context: composite
Measurement source: S29 · Figure S40

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Portable device calibration intercept	-0.128	—	—	Caption Exact Reported	S29 · Figure S40
Portable device calibration residual probability value	2.75E-14	—	—	Caption Exact Reported	S29 · Figure S40
Portable device calibration R2	0.9997	—	—	Caption Exact Reported	S29 · Figure S40
Portable device calibration slope	y = 1.008x - 0.128	—	—	Caption Exact Reported	S29 · Figure S40

paper sensor response speed

I2@FeTHQ/FP paper sensor · Thin Film

I2@FeTHQ/FP compared with I2@FeTHQ/SPE and I2@FeTHQ/IE

Geometry: paper/SPE/IE
Context: composite vs controls
Measurement source: 7-8 · Results · Figure 5b

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
I2@FeTHQ/FP response speedMarked as a best value within this paper	2.2 s	—	—	Text Exact Reported	6-7 · Results · Figure 5b
I2@FeTHQ/IE response speed	~4.1 s	—	—	Figure Axis Approximate	8 · Results · Figure 5b
I2@FeTHQ/SPE response speed	~9.1 s	—	—	Figure Axis Approximate	8 · Results · Figure 5b
I2@FeTHQ/FP one-month signal decay	~3.5%	—	—	Text Approximate	7 · Results · Figure 5c

sweat AA accuracy and stability

I2@FeTHQ/FP paper sensor · Thin Film

On-skin/sweat samples compared with HPLC and standards; 15 mg sweat loading

Geometry: paper sensor device
Context: composite
Measurement source: 7-8 · Results · Figure 5e; Figure S41-S44

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Average detection error vs HPLC	~6.8%	—	—	Text Approximate	7 · Results · Figure 5e
Sweat loading for quantitative analysis	approximately 15 mg	—	—	Text Approximate	7 · Results · Figure S41
Parallel 15 mg sweat AA average	17.46 uM	—	—	Caption Exact Reported	S30 · Figure S41
Parallel 15 mg sweat AA RSD	0.03%	—	—	Caption Exact Reported	S30 · Figure S41
Sweat sample 1 measured AA	10.21 +/- 0.26 uM	—	+/- 0.26 uM	Caption Exact Reported	S31 · Figure S44
Sweat sample 2 measured AA	19.83 +/- 0.25 uM	—	+/- 0.25 uM	Caption Exact Reported	S31 · Figure S44
Sweat sample 3 measured AA	49.82 +/- 0.31 uM	—	+/- 0.31 uM	Caption Exact Reported	S31 · Figure S44

pH effect on AA sensing

I2@FeTHQ/ITO working electrode · Electrode

500 uM AA; pH 5-9

Geometry: ITO
Context: target
Measurement source: S23 · Figure S28

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
AA current density at pH 5	~0.066 mA cm-2	—	—	Figure Axis Approximate	S23 · Figure S28
AA current density at pH 6	~0.106 mA cm-2	—	—	Figure Axis Approximate	S23 · Figure S28
AA current density at pH 7Marked as a best value within this paper	~0.162 mA cm-2	—	—	Figure Axis Approximate	S23 · Figure S28
AA current density at pH 8	~0.112 mA cm-2	—	—	Figure Axis Approximate	S23 · Figure S28
AA current density at pH 9	~0.090 mA cm-2	—	—	Figure Axis Approximate	S23 · Figure S28
Optimum AA sensing pH	pH 7.0	—	—	Text Rounded Reported	5 · Results · Figure S28

CV scan-rate AA sensing

I2@FeTHQ/ITO working electrode · Electrode

AA in 0.1 M PBS, pH 7, 500 uM; scan rates 10-200 mV/s

Geometry: ITO
Context: target
Measurement source: 4-5 · Results · Figure 2b-c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Anodic peak current vs scan-rate square-root R2	R2 = 0.999	—	—	Figure Axis Approximate	4 · Results · Figure 2c
Cathodic peak current vs scan-rate square-root R2	R2 = 0.996	—	—	Figure Axis Approximate	4 · Results · Figure 2c
CV scan-rate range	10-200 mV s-1	—	—	Caption Range	4 · Results · Figure 2b

chronoamperometry selectivity

Chronoamperometry

I2@FeTHQ/ITO working electrode · Electrode

AA vs KCl, NaCl, dopamine, L-cysteine, glucose, MgCl2, uric acid, lactic acid

Geometry: ITO
Context: target
Measurement source: 5 · Results · Figure 2f; Figure S29-S31

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
AA relative response	100%	—	—	Caption Exact Reported	5 · Results · Figure 2f
Dopamine relative response	~8%	—	—	Figure Axis Approximate	4 · Results · Figure 2f
Glucose relative response	~9%	—	—	Figure Axis Approximate	4 · Results · Figure 2f
KCl relative response	~7%	—	—	Figure Axis Approximate	4 · Results · Figure 2f
Lactic acid relative response	~16%	—	—	Figure Axis Approximate	4 · Results · Figure 2f
L-cysteine relative response	~7%	—	—	Figure Axis Approximate	4 · Results · Figure 2f
MgCl2 relative response	~12%	—	—	Figure Axis Approximate	4 · Results · Figure 2f
NaCl relative response	~8%	—	—	Figure Axis Approximate	4 · Results · Figure 2f
Uric acid relative response	~5%	—	—	Figure Axis Approximate	4 · Results · Figure 2f

AA sensor stability/recyclability/reproducibility

I2@FeTHQ/ITO working electrode · Electrode

Repeated CV/sensing cycles and independent electrodes for 500 uM AA

Geometry: ITO
Context: target
Measurement source: 5 · Results · Figure 2g-i

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Retained sensing activity after 5 runs	about 98%	—	—	Text Approximate	5 · Results · Figure 2h
Recyclability RSD after 5 runs	1.01%	—	—	Text Exact Reported	5 · Results · Figure 2h
Independent electrode reproducibility RSD	2.04%	—	—	Text Exact Reported	5 · Results · Figure 2i
Single AA-test CV stability	negligible CV changes on continuous scanning	—	—	Text Qualitative	5 · Results · Figure 2g