Dyes in Analytical Chemistry: Essential Tools for Accurate Detection and Analysis
Dyes are essential tools in analytical chemistry, with applications ranging from spectrophotometric analysis to complexometric titrations and chromatography. Their ability to form complexes, indicate pH changes, and enhance detection sensitivity makes them invaluable for researchers and analysts. By choosing the appropriate dye for specific applications, scientists can achieve accurate and reliable results, paving the way for advancements in various fields, including environmental monitoring, pharmaceuticals, and biomedical research.
Absorbance Photometry and Fluorescence Analysis
Rhodamine dyes are one of the commonly used dyes in analytical chemistry. Since the 1990s, rhodamine dyes have been widely used in absorptiometry and fluorescence analysis. More than 50 substances have been measured using rhodamine dyes with high sensitivity. In addition, cyanine dyes have also been widely used in biological and chemical analysis due to their wide spectral range, high molar extinction coefficient, high fluorescence quantum yield and high sensitivity.
Application Example: Rhodamine derivatives have been widely used in chemical sensors due to their unique structural characteristics and excellent photophysical properties. When rhodamine is present in a helical ring, there is no obvious fluorescence. When it is coordinated or hydrolyzed in the interaction with a specific substance, the helical ring will open with strong fluorescence. Therefore, the structure of rhodamine is an ideal template for constructing chelation enhanced fluorescence (CHEF) probes. Based on the excellent photophysical properties of rhodamine, two CHEF solid-state sensors for Hg (II) were constructed by introducing polycyclic aromatic hydrocarbons (PAHs) naphthalene and pyrene as fluorophores, which have a large electron conjugated system, good rigidity and coplanarity, strong fluorescence and stability. The detection limit can reach 0.065µmol/L.
Kinetic Analysis
Dyes are also widely used in kinetic analysis. The absorption and emission characteristics of dyes can be used to accurately determine the rate of chemical reactions. For example, the application of triphenylmethane dyes in catalytic spectrophotometry and electroanalysis demonstrates their important role in trace analysis.
Application Example: Radiation-induced molecular fragmentation in triphenylmethane aromatic dyes was evaluated using gas chromatography-mass spectrometry to detect lower concentrations of volatile and radiation-synthesized fragments in irradiated samples. This technique provides in-depth information on the radiation-induced fragmentation of triphenylmethane, given its sensitivity, selectivity, and ability to quantify radiation-induced fragments compared to other optical-based techniques. The GC-MS spectrum of pristine TPM was determined to be the basis for the differences between irradiated and non-irradiated material. Two radiation-induced derivatives were identified and quantified. Namely, 2-propanone-1,1-diphenylmethane (DPP) and benzyl alcohol, α,α-diphenylmethane (BMDP).
Biomedical Research
NIR-II fluorescence imaging technology utilizes dyes to significantly improve the sensitivity and specificity of disease detection and diagnosis in biomedical research and clinical practice. The unique advantages of this technology have made fluorescence imaging widely used in analytical chemistry, chemical biology, and biomedical engineering.
Application Example: Exosome-liposome hybrid-based vehicles (ELV) show promise as carriers for cancer treatment, but effective theranostic probes to label their lipid membranes are scarce. Study has reported the design and synthesis of lipophilic NIR-II cyanine dyes that label ELV membranes for NIR-II fluorescence imaging and targeted photothermal therapy of subcutaneous glioblastoma. The synthesized ELV (NIR-C12-EL) combines NIR-C12 labeling and cyclic arginylglycylaspartic acid for enhanced targeting, exhibiting excellent stability, biocompatibility, and high photoconversion efficiency (62.28%).
Protein Quantitative Analysis
The application of industrial dyes in the field of chemical quantitative analysis is a bold attempt. It provides new ideas for the search for new spectral dye probes and greatly reduces the cost of protein quantitative analysis. The application of dye binding method makes protein quantitative analysis more efficient and economical.
Application Example: Near instant surface-selective fluorescent protein quantification was performed using sulfonated triarylmethane dyes and fluorescein-activated proteins. This method uses a fluorogen activating protein (FAP) as a protein tag and a sulfonated malachite green (MG) dye as a cell-excluded marker. The MG-B-Tau 1 dye binds to the dL5** FAP with subnanomolar affinity, producing a measurable fluorescence signal within seconds. Compared to PEG-modified dyes, MG-B-Tau 1 with dual sulfonate groups shows improved specificity, over tenfold reduced fluorescence on dead cells, limited plasma membrane penetration, and over twice the quantum yield of previous dyes like MG-11p.
References
- Liu, Yuanyuan, et al. "Rhodamine 6G-PAH probes for heavy metal: Fluorescence detection, bioimaging, and solid-phase sensing application." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 325 (2025): 125070.
- Abd El-kareem, Mamoun SM, et al. "Elucidation of radiation-induced molecular fragmentation in triphenylmethane aromatic dye using mass spectrometric tool." Radiation Physics and Chemistry (2024): 112284.
- Liu, Yue, et al. "Engineering of exosome-liposome hybrid-based theranostic nanomedicines for NIR-II fluorescence imaging-guided and targeted NIR-II photothermal therapy of subcutaneous glioblastoma." Colloids and Surfaces B: Biointerfaces 245 (2025): 114258.
- Yan, Qi, et al. "Near-instant surface-selective fluorogenic protein quantification using sulfonated triarylmethane dyes and fluorogen activating proteins." Organic & biomolecular chemistry 13.7 (2015): 2078-2086.
Contact Us
Send Us a Request
What is your specific need? We will do everything we can to meet your
expectations.
Online Inquiry
