Trinder’s Reagents in Modern Biochemical Assays: From Classical Phenols to Advanced Aniline Derivatives

Introduction: Understanding the Trinder Reaction

The Trinder reaction was first described by P. Trinder in the 1960s, originally as a colorimetric assay for glucose and other oxidase substrates. The method relies on the use of peroxidase (POD) to catalyze the oxidation of a chromogenic hydrogen donor in the presence of hydrogen peroxide (H₂O₂).

The Trinder reaction is a peroxidase-catalyzed oxidative coupling reaction.

• Step 1: An oxidase enzyme (e.g., glucose oxidase, cholesterol oxidase) reacts with the substrate (e.g., glucose, cholesterol), producing H₂O₂.
• Step 2: In the presence of peroxidase (POD), H₂O₂ oxidizes a chromogenic donor (Trinder reagent).
• Step 3: The oxidized intermediate couples with a 4-aminoantipyrine (4-AA) or similar aromatic amine, producing a quinoneimine dye with strong absorbance in the visible region.

Mechanism equation (simplified):

1. Substrate (e.g., glucose) + O₂ → (oxidase) → H₂O₂ + product

2. H₂O₂ + TOPS + 4-AA → (POD) → Quinoneimine dye + 2H₂O

Tips:  TOPS = N-Ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline sodium salt

TOPS is a modern Trinder’s reagent, highly water-soluble and stable.

The intensity of the dye color (usually pink/red) is proportional to the concentration of the analyte.

The Trinder reaction became popular in clinical biochemistry because it allowed rapid, simple, and accurate quantification of analytes like glucose, cholesterol, uric acid, and creatinine in biological fluids. The reagents used in this reaction became known as “Trinder’s reagents”—a family of phenolic or aniline derivatives that undergo oxidative coupling to produce colored products.

Emergence of Modern/New Trinder’s Reagents: Traditional vs. Modern Reagents

Feature	Traditional Trinder’s Reagents	Modern/New Trinder’s Reagents
Typical Types	Phenolic (phenol, 4-chlorophenol, dichlorophenol sulfonate), and aniline derivatives (e.g., N,N-dialkyl-aniline)	Aniline-sulfonate salts like TOOS, TOPS, ADPS, ADOS, ALPS, DAOS, MAOS, MADB
Solubility	Poor aqueous solubility; often requires distillation or recrystallization	High water solubility; easy to dissolve and use in assays
pH Range Compatibility	Narrower, often acidic; may impair enzyme activity (limiting assay pH window)	Wide pH range (typically 7–10), compatible with many enzymes and buffers
Color Stability & Fading	Less stable; prone to fading or forming precipitates over time	Stable color products; minimal fading for reagents like TOOS, ADOS, DAOS
Interference & Wavelength	Absorption often between 500–520 nm, overlapping with bilirubin and hemoglobin, causing interference	Products absorb >540 nm (often 550–630 nm), reducing spectral overlap and interference
Sensitivity	Modest; phenols generally produce weaker signals	Higher molar absorptivity and signal; ALPS, TOOS, TOPS show strong responses
Ease of Use / Preparation	Requires laborious pretreatment (e.g. distillation, recrystallization)	Ready-to-use salts with consistent purity and performance
Cost	Generally lower cost, simpler chemicals	Slightly higher cost, but better performance offers value in many applications

Application Spectrum of New Trinder’s Reagents

Current Applications

New Trinder’s reagents are widely used in biochemical analysis, especially where oxidase–peroxidase systems are applied:

• Clinical Diagnostics (IVD): Routine assays for glucose, cholesterol, triglycerides, uric acid, creatinine, and other metabolites; resistant variants (DAOS, MAOS, MADB) help minimize hemolysis and lipemia interference.
• Point-of-Care Testing & Biosensors: Incorporated into test strips, dry chemistry, and chip-based biosensors due to high solubility and color stability.
• Food & Beverage Quality Control: Determination of sugars, alcohols, and fermentation products.
• Biopharma & Enzyme Studies: Enzyme activity assays and kinetic studies with oxidases and peroxidases.
• Environmental & Industrial Testing: Detection of hydrogen peroxide and oxidase activity in water and environmental samples.

Future Directions

The unique solubility, stability, and wavelength properties of new reagents open pathways for advanced uses:

• Wearable & Continuous Biosensors: Integration into continuous glucose monitors and implantable devices.
• Multiplexed Assays: Exploiting distinct λmax values (540–630 nm) for simultaneous multi-analyte detection with minimal signal overlap.
• Microfluidics & Lab-on-a-Chip: Application in portable diagnostic platforms and paper-based devices.
• High-Throughput Screening: Use as universal redox reporters in drug discovery and enzyme inhibitor studies.
• Biomedical Research: Monitoring oxidative stress biomarkers in cancer, neurodegenerative disease, and personalized medicine.
• Green Analytical Chemistry: Safer alternatives to phenol-based systems, suitable for environmentally friendly diagnostics and teaching labs.

How to Select the Right Trinder’s Reagent

1) Match the wavelength to your instrument & matrix

• If your photometer has 540–555 nm filters and the matrix is clean (e.g., serum with minimal hemolysis/lipemia), use ADPS (540), ADOS (542), TOPS (550) or TOOS (555). They’re standard, robust pairings with 4-AA.
• If you need to reduce hemoglobin/turbidity interference, move to longer wavelengths: DAOS (593), MAOS (630) or MADB (630). Hemoglobin/lipemia absorb strongly around 500–550 nm; measuring further into the red minimizes positive bias.

2) Consider sensitivity (molar absorptivity / relative intensity)

• From Dojindo’s data (vs phenol systems), higher relative intensity ≈ stronger signal:
  ALPS ~3.25×, TOOS ~3.08×, TOPS ~2.9×, ADPS ~2.19×, ADOS ~2.1×, MAOS ~1.79×, DAOS ~1.38×. If you want maximum signal on common filters, ALPS (561), TOOS (555) or TOPS (550) are excellent picks.

3) pH window & enzyme compatibility

• Typical working pH windows (from the catalog) are broad (≈7–10) for ADOS, ALPS, DAOS, TOPS, MAOS; TOOS is optimal 8.5–9.5. Choose the reagent whose pH range aligns with your enzyme and buffer system. (See the sheet for each reagent’s pH band.)

4) Stability and coupler choice

• All entries above are 4-AA coupler systems. Alternatives like MBTH can push wavelengths longer but tend to give higher blanks / poorer solution stability; for routine diagnostics 4-AA systems are generally preferred.

Aladdin’s Trinder’s Reagents and related products

Here is Trinder’s Reagents with detailed information.

Aladdin catalog	Abbrev	Full Chemical Name	CAS Number	λmax with 4-AA (nm)	Assay pH Range	Notes / Typical Usage
E110908  A405656	ADPS	N-Ethyl-N-(3-sulfopropyl)-3-methoxyaniline, sodium salt,	82611-88-9	540	8.0–9.5	High solubility, stable; standard diagnostic assays (glucose, cholesterol).
E113054	ADOS	N-Ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methoxyaniline, sodium salt, dihydrate	82692-96-4	542	7.0–10.0	Similar to ADPS but broader pH; good for enzyme assays with varied buffers.
E113052	TOPS	N-Ethyl-N-(3-sulfopropyl)-3-methylaniline, sodium salt,	40567-80-4	550	8.0–10.0	Standard in many IVD kits; strong chromogenic response, stable.
T105328	TOOS	N-Ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline, sodium salt,	82692-93-1	555	8.5–9.5	Excellent solubility and color stability; widely used for glucose/cholesterol assays.
E113055	ALPS	N-Ethyl-N-(3-sulfopropyl)aniline, sodium salt	82611-85-6	561	7.5–10.0	Very high relative intensity (≈3.25× phenol); great when sensitivity is critical.
D108991	DAOS	N-Ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethoxyaniline, sodium salt	83777-30-4	593	7.0–10.0	λmax shifted into red region; minimizes hemoglobin/bilirubin interference.
M113057	MAOS	N-Ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethylaniline, sodium salt, monohydrate	82692-97-5	630	8.0–10.0	Red-shifted; useful in lipemic/hemolyzed samples; stable chromophore.
M113056	MADB	N,N-Bis(4-sulfobutyl)-3,5-dimethylaniline, disodium salt	209518-16-1	630	~5.5–9.5	Similar to MAOS; strong red absorbance; reduces sample background interference.
H102992	HDAOS	N-(2-Hydroxy-3-sulfopropyl)-3,5-dimethoxyaniline, sodium salt	82692-88-4	583	5.5–7.5	Highly soluble; stable purple/blue dyes in 4-AA or MBTH Trinder reaction assays
S733403	TODB	N,N-Bis(4-sulfobutyl)-o-toluidine, disodium salt	1044537‑70‑3	550	8.5–9.5	High solubility; used in triglyceride, cholesterol, lipid assays
N104910  N274358  N104908	NBT	Nitro Blue Tetrazolium chloride	298-83-9	Not specified	Method-dependent	Classic SOD (superoxide dismutase) assay indicator; also used in NBT/BCIP histochemical staining.
B105508	BT	Blue tetrazolium chloride (Tetrazolium blue)	1871-22-3	Not specified	Method-dependent	Used in succinate dehydrogenase (SDH) activity assays; requires DMSO extraction of formazan.
I105499	INT	Iodonitrotetrazolium chloride	146-68-9	Not specified	Method-dependent	Used in dehydrogenase assays as an electron acceptor; reduced to red formazan.

Some other RELATED products provided by Aladdin

Aladdin catalog	Product name	Purity	CASNO.
A106066	4-Aminoantipyrine	≥98%	83-07-8
A426146	4-Aminoantipyrine	10mM in DMSO	83-07-8
P755498	Peroxidase from horseradish	Type I, essentially salt-free, lyophilized powder,≥50 units/mg solid (using pyrogallol);	9003-99-0
P755413	Peroxidase from horseradish	Type X, ammonium sulfate suspension	9003-99-0
P128534	Peroxidase from horseradish(EIA Grade,Purified)	RZ 2.9,≥500 units/mg protein	9003-99-0
P105525	Horseradish Peroxidase (HRP)	＞200 U/mg, RZ 2-4	9003-99-0
P105526	Horseradish Peroxidase (HRP)	＞150 U/mg， Rz ＞2	9003-99-0
P578793	Horseradish Peroxidase (HRP)	＞100 U/mg Pyrogallol , Rz＞1	9003-99-0
P105528	Horseradish Peroxidase (HRP)	≥250 U/mg，Rz≥3	9003-99-0
P298979	Peroxidase from horseradish（HRP）	＞180 units/mg	9003-99-0

About us

Aladdin offers a full range of high-purity Trinder’s reagents for oxidase–peroxidase colorimetric assays. These reagents are widely used in clinical diagnostics, food testing, enzyme studies, and biosensor development. Our portfolio covers key products such as TOOS, TOPS, ADPS, ADOS, ALPS, DAOS, MAOS, MADB, HDAOS, and TODB etc.. This allows researchers to choose the best option for sensitivity, stability, or interference resistance.

Aladdin’s Trinder’s reagents produced with high purity and consistency, ensuring reliable results in both routine testing and advanced research. They are trusted tools across fields including metabolic disease, cardiovascular health, enzymology, and environmental monitoring.

Aladdin: https://www.aladdinsci.com/