3,5-DiBr-PAESA: Comprehensive Analysis of a High Sensitivity Metal Ion Chromogenic Reagent
Accurate quantitative detection of metal ions has always been an important topic in the fields of analytical chemistry and biomedical research. 3,5-DiBr-PAESA (chemical name: 4- (3,5-dibromo-2-pyridylazo) – N-ethyl-N – (3-sulfonylpropyl) aniline, monosodium salt, monohydrate), as an ultra sensitive color chelating agent, plays a key role in the detection of metal ions such as copper and silver due to its excellent properties.
1. Basic information of 3,5-DiBr-PAESA
English name: 3,5-DiBr-PAESA
CAS number: 100743-65-5
Molecular formula: C ₁₆ H ₁₈ Br ₂ N ₄ O ∝ S (or C ₁₆ H ₁₇ Br ₂ N ₄ NaO ∝ S · H ₂ O)
Molecular weight: 506.21 (or 546.21, depending on whether crystal water is calculated)
Appearance: Deep red brown powder
Solubility: Dissolve in water to form a clear red solution
Structural formula:
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2.Working principle: High sensitivity comes from a unique chemical mechanism
The core function of 3,5-DiBr-PAESA is to undergo chelation reactions with specific metal ions to generate colored complexes, which can be quantitatively analyzed by spectrophotometry.
1）Copper ion (Cu ² ⁺) determination:
In a weakly acidic environment (pH 4.7), copper ions in the sample dissociate from proteins such as ceruloplasmin. Under the action of reducing agents such as ascorbic acid, Cu ² ⁺ is reduced to Cu ⁺, and then forms a stable blue chelate with 3,5-DiBr-PAESA. The blue complex has a maximum absorption peak at a wavelength of approximately 580-638 nm, and its color intensity is proportional to the concentration of copper ions. The molar absorptivity of its copper complex is as high as 1.24 × 10 ⁵ L mol ⁻¹ cm ⁻¹, which is much higher than similar reagents such as PAR (7.18 × 10 ⁴) and PAN (5.21 × 10 ⁴), indicating a sensitivity increase of 1.7 to 2.4 times.
2）Silver ion (Ag ⁺) determination:
3,5-DiBr-PAESA is also suitable for the detection of silver ions. A study developed a flow injection spectrophotometric method using EDTA to mask the interference of copper ions and the high formation constant of AgBr (K=12.3) to accurately determine silver ions at the sub mg/dm ³ level in strongly acidic and high concentration copper solutions.
3.Performance Data Overview
1）Detection wavelength: Copper ion determination usually reads the absorbance at 570-590 nm (commonly 580 nm), and its copper complex has a higher absorption peak at 637-639 nm.
2）Detection range and sensitivity: Based on its method, the detection range of copper can reach 3-400 µ g/dL, and the sensitivity (detection limit) can be as low as 1.84 µ mol/L.
3）Precision: The coefficient of variation (C.V.) within a batch is usually less than 5%, ensuring the reproducibility of the results.
4.Application scenario: From laboratory to industrial site
3,5-DiBr-PAESA has a wide range of applications, covering multiple levels:
1）Clinical diagnosis:
Used to detect copper content in biological samples such as serum and plasma, it is an important tool for evaluating copper metabolism in clinical testing.
2）Environmental monitoring:
It can be used for the detection of trace copper in wastewater (such as dental clinic wastewater), with a detection limit (LOD) of up to 0.02 ng/mL, meeting strict environmental monitoring requirements.
3）Industrial process control:
In industries such as printed circuit board manufacturing, precise monitoring of silver ion concentration in copper plating solutions is used to ensure product quality.
4）Basic research:
As a highly sensitive analytical reagent, it is used for quantitative experiments of metal ions in life sciences and chemical research.
5.Summary
3,5-DiBr-PAESA plays an irreplaceable role in many fields that require precise measurement of metal ions such as copper and silver due to its ultra-high sensitivity, good water solubility, and selectivity. Whether in clinical laboratories, environmental testing stations, or industrial production lines, it is a high-performance color developer. Its unique molecular structure endows it with detection capabilities superior to traditional reagents, making it a reliable tool in the hands of analytical chemists.
Product Manager Email:ada@coreychem.com
