Ferrozine sodium CAS: 69898-45-9 classic colorimetric reagent

Product Overview:

Ferrozine (monosodium salt) is a reagent used for the spectrophotometric determination of iron. It reacts with ferrous iron (Fe²⁺) to form a stable magenta-colored complex. As a classic chromogenic reagent, Ferrozine exhibits high selectivity toward Fe²⁺, and the resulting complex shows maximum absorption at 562 nm with intense color and excellent stability, enabling reliable quantification of iron at trace levels. Since its introduction, the Ferrozine assay has become a standard method in water quality monitoring, clinical diagnostics, food analysis, and life science research. With excellent water solubility, high molar absorptivity, and outstanding selectivity, Ferrozine remains the reagent of choice for laboratories and IVD manufacturers worldwide.

Product information:

Frequently Asked Questions (FAQ)

Q1: What is the detection principle of Ferrozine monosodium salt? Why do we measure at 562 nm?

Ferrozine is a strong chelating ligand composed of a 1,2,4-triazine ring, a pyridyl group, and two benzenesulfonic acid groups. It reacts selectively with Fe²⁺ in a 3:1 stoichiometric ratio, forming a stable magenta-colored complex. This complex shows a characteristic absorption peak at 562 nm, with a molar absorptivity as high as approximately 27,900–31,500 M⁻¹·cm⁻¹. According to the Lambert-Beer law, absorbance increases linearly with iron concentration. Therefore, you can quantify iron directly without organic solvent extraction.

For total iron determination, first reduce Fe³⁺ to Fe²⁺ with a reducing agent, such as ascorbic acid or hydroxylamine hydrochloride. If you need to differentiate iron species, measure Fe²⁺ first and then total iron. The difference between the two values corresponds to the Fe³⁺ content.

Q2: What advantages does Ferrozine offer over traditional iron chromogenic reagents (such as o-phenanthroline and 2,2′-bipyridine)?

Compared with traditional reagents, Ferrozine offers four outstanding advantages: higher sensitivity, stronger selectivity, simpler operation, and excellent water solubility. Specifically, its sulfonate groups allow direct use in aqueous buffer systems (typically acetate buffer, pH 4–5) without extraction. Meanwhile, its excellent selectivity toward Fe²⁺ keeps interference from common coexisting metal ions to a minimum.

As a result, Ferrozine serves a wide range of fields: clinical testing (serum iron and TIBC assays), life science research (iron metabolism and ferroptosis), environmental monitoring (iron speciation in water), and food and pharmaceutical analysis. Moreover, IVD assay kit manufacturers rely on it as a core chromogenic raw material.

Q3: What is the difference between Ferrozine monosodium salt and disodium salt? How should I choose when purchasing?

Both salts share the same chemical parent structure. The only difference lies in the salt form of the sulfonic acid groups. The monosodium salt (this product, CAS 69898-45-9) has one sulfonate group as the sodium salt and the other as the free acid. Its molecular formula is C₂₀H₁₃N₄NaO₆S₂, and its molecular weight is 492.46. By contrast, the disodium salt has both sulfonate groups in sodium salt form.

In terms of Fe²⁺ color development, however, the two are fully equivalent. When purchasing, we therefore recommend verifying the CAS number and molecular weight to confirm the salt form, and then selecting according to your process requirements (solubility, pH, cost).

Q4: How should I choose the purity grade? What quality documents come with each batch?

For routine colorimetric analysis, the ≥98% (HPLC) grade is sufficient. However, if you work with IVD reagent formulations, clinical testing, or high-sensitivity research, we recommend the ≥99% high-purity grade. This helps minimize background interference and ensures batch-to-batch consistency. COA will be attached for every batch, including purity, water content, appearance, and other test data. For SDS and additional technical documents, please feel free to contact the product manager.

Application Cases

Ferrozine offers high sensitivity, strong selectivity, and simple operation. It has become a mature reagent in clinical diagnostics, life sciences, environmental science, and industrial quality control. Five representative applications are listed below:

Case 1: Clinical Testing — Serum Iron and TIBC Determination

Ferrozine is the core chromogenic reagent in clinical chemistry analyzers and IVD assay kits. It is used to determine serum iron, unsaturated iron-binding capacity (UIIBC), total iron-binding capacity (TIBC), and transferrin saturation. The reagent delivers stable color development, a wide linear range, and excellent batch-to-batch reproducibility. It is adopted as a standard raw material by clinical reagent manufacturers worldwide. These assays help clinicians diagnose iron-deficiency anemia, iron overload, and hemochromatosis, and form a common basis for anemia differential diagnosis.

Case 2: Iron Metabolism and Ferroptosis Research

Ferrozine-based colorimetric assays are widely used in life science research. They enable quantitative iron analysis in cells, tissues, mitochondria, and the cellular labile iron pool (LIP). A classic protocol was described by Riemer et al. (Anal. Biochem. 2004). Researchers rely on this method to study iron metabolism disorders, ferroptosis mechanisms, and drug effects on iron homeostasis. It has become a common data source in iron biology publications.

Case 3: Environmental Water Analysis — Fe(II)/Fe(III) Speciation

The Ferrozine method is well established for determining dissolved Fe²⁺/Fe³⁺ speciation in natural waters, seawater, and sediment pore water (Viollier et al., Appl. Geochem. 2000). It is highly sensitive and suitable for on-site colorimetric measurement. The method is a standard tool for studying iron cycling and redox processes in marine and freshwater environments. Environmental laboratories also use it to monitor trace iron in surface water, groundwater, and effluents, supporting compliance with drinking water and discharge standards.

Case 4: Iron Content Testing in Foods, Supplements, and Pharmaceuticals

The Ferrozine colorimetric method is applied to quality control of total iron in foods, dietary supplements, pharmaceuticals, and nutritional fortificants — such as fortified cereals, dairy products, and infant formula. It verifies label claims and nutritional compliance. Compared with instrumental methods such as flame atomic absorption spectroscopy, it is simpler to operate, lower in cost, and higher in throughput. This makes it ideal for routine screening and factory release testing of large sample batches.

Case 5: Academic Research, Education, and Assay Kit Development

As a classic chromogenic reagent in coordination chemistry, Ferrozine is widely used in university teaching experiments, calibration curve standardization, and laboratory proficiency testing. It is also a key chromogenic component in research-grade iron assay kits and microfluidic/automated biochemical analysis systems, ensuring stable market demand.

Safety and Storage

• Safety: Not dangerous goods. For laboratory use only. Avoid inhalation of dust and contact with skin and eyes. Wear appropriate personal protective equipment (gloves, safety glasses). Refer to the Safety Data Sheet (SDS) before handling.
• Storage: Store at low temperature for long-time storage. Transport at room temperature. Keep  the container tightly closed in a cool, dry, and well-ventilated place, protected from light and moisture. Store away from strong oxidizing agents.
• Shelf Life: 24 months when stored properly.

Product Manager:

Grace Zhang  E-mail: grace@coreychem.com