Pichayaporn Nuihuaykaew, Tanaporn Sribunpeng, Phatchanamon Jantivas, Rattikan Chantiwas*
Department of Chemistry and Center of Excellence for Innovation in
Chemistry, Faculty of Science, Mahidol University, Rama VI Rd., Bangkok 10400,
Thailand
* Corresponding author. E-mail
address: rattikan.cha@mahidol.ac.th (R. Chantiwas).
Abstract:
This
study introduces a fabrication-free headspace tape-based colorimetric method
for rapid and high-throughput screening of nitrite in processed meat products,
employing a commercial adhesive tape (CAT) as the optical readout substrate.
Nitrite is converted to volatile iodine via an acid-mediated nitrite–iodide
redox reaction in a 96-well plate, thereby facilitating physical separation
between the reaction medium and the optical detection surface. The iodine vapor
produced is captured on the adhesive layer, resulting in a visible color change
that is quantified through digital image analysis using a flatbed scanner. The
adhesive surface enables uniform iodine adsorption and stable color development
across the sensing area, thereby enabling reproducible image-based readout and
high-throughput analysis in a 96-microwell plate. Commercial adhesive tapes
were evaluated, and CAT1 (Scotch® Magic™ Tape 810) was identified as a suitable
substrate for iodine vapor capture due to its color response and
reproducibility. The optimized conditions were evaluated and gave a linear
response over the nitrite concentration range of 0.5–2.5 mM (R2 > 0.99),
with an LOD of 0.17 mM, and inter-day precision was acceptable (10%
RSD, n = 12). Excellent well-to-well reproducibility was
attained across all 96 microwells, with a relative standard deviation (RSD) of
less than 2%, thereby indicating minimal positional effects and a consistent
signal distribution. Furthermore, temporal stability was observed, maintaining
consistency over analysis durations of up to 90 min, with only minor
variations in signal strength. The method showed acceptable selectivity, with
minimal interference from common matrix components, although reductive species
might interfere by consuming iodine. The method requires no reagent
immobilization, surface modification, or organic solvents, resulting in a high
Analytical GREEness (AGREE) score of 0.79. The sample preparation also
demonstrated favorable greenness according to the AGREEprep metric (0.81),
reflecting simple aqueous extraction and minimal handling. The colorimetric
response remained stable over time, supporting reliable analysis. Its
applicability was further confirmed by recovery studies on processed meat
samples, which yielded recoveries of 80–110%, demonstrating its suitability as
a rapid and practical screening method for nitrite in food safety monitoring.
KEYWORDS
Nitrite
screening; Headspace colorimetry; Iodine vapor sensing; Adhesive
tape sensor; Green analytical chemistry; Processed meat products
Reference:
Nuihuaykaew, P.; Sribunpeng, T.; Jantivas, P.; Chantiwas, R. A fabrication-free headspace tape-based colorimetric method for rapid high-throughput nitrite screening in processed meats. Microchemical Journal 2026, 227, 118555. doi: 10.1016/j.microc.2026.118555
