# Istanbul Technical University probe NIR-2 detects mercury ions in water and food in 10 seconds

- Published: 2026-11-15 13:42 UTC
- Section: Science › Instruments & experiments
- Tags: Hg2+ detection, mercury sensor, NIR-2 probe, near-infrared fluorescence, colorimetric probe, smartphone detection, mercury in food, mercury in water, Istanbul Technical University
- URL: https://realtech.media/news/rt-026b43071ac289fee5708139_istanbul_technical_university/

**The NIR-2 molecular probe changes color and fluoresces in the presence of Hg2+; in laboratory tests, a smartphone camera was used for readout.**

![Istanbul Technical University probe NIR-2 detects mercury ions in water and food in 10 seconds](https://realtech.media/media/2026/11/03b8707e0bc63cd3.jpg)
*William C. Shrout, Wikimedia Commons, Public domain*

Researchers at Istanbul Technical University have developed NIR-2, a near-infrared fluorescent and colorimetric probe for quantifying Hg2+ ions in real samples, according to a study in Talanta [1]. The probe responds to mercury within 10 s. The authors report detection limits of 3.77 × 10^-10 M by UV-Vis and 4.54 × 10^-9 M by fluorescence [1].

## How the probe works

In its initial state, NIR-2 has a ring-closed selenolactone structure with fluorescence switched off. Interaction with Hg2+ converts it to a ring-open acid form, which produces a visible color shift and a marked rise in fluorescence [1]. HRMS, FT-IR and NMR spectroscopy confirmed the molecular structure and the interaction mechanism [1].

According to the publication's retelling, the solution turns from yellow to green and emits near-infrared light, so mercury can be detected by eye or with instruments that measure light outside the visible range. The signal remained stable for at least 20 minutes.

## Tests in water, food and cells

The probe was validated on water and food samples and showed high recovery rates [1]. Known amounts of mercury were added to drinking water, lake water and several fruits. Color responses were also examined in rice, corn, beans and lentils, and performance varied between foods.

The team also developed a smartphone-based method: mercury levels were estimated by comparing red and green values in photographs. The authors report a range of 1.66 × 10^-9 M to 7.50 × 10^-6 M and state that, to their knowledge, it is the most sensitive smartphone-based Hg2+ detection reported in the literature [1].

In a separate experiment, the probe gave mercury-related fluorescence signals in human lung cells. Toxicity assessments and imaging studies indicated that NIR-2 works in a biological environment [1]. Cell survival stayed above 90% under the tested conditions.

The work remains at the laboratory stage. Samples required preparation, lighting was controlled, and most tests used materials with deliberately added mercury. How reliably the probe performs on naturally contaminated samples and under changing field conditions has yet to be established.

## Sources

1. [Talanta](https://doi.org/10.1016/j.talanta.2026.129679)
2. [knowridge.com](https://knowridge.com/2026/11/new-sensor-could-reveal-hidden-mercury-in-food-and-water)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-026b43071ac289fee5708139_istanbul_technical_university/