Quantitative Determination of Target Element in Biological samples

1.Enzymatic Detection

(1) New Trinder’s Reagents (Oxidase system)

New Trinder‘s Reagents, which are highly water-soluble aniline derivatives, are applicable for the colorimetric determination of hydrogen peroxide. In the presence of a coupler such as 4-aminoantipyrine(4-AA), the Trinder‘s reagents are oxidized with peroxidase and two molecules of hydrogen peroxide and are developing the color to purple or blue.


(2) Tetrazolium Salts and Electron Mediators (Dehydrogenase system)

Tetrazolium salts have been developed to determine dehydrogenase activity which oxidizes its substrate and reduces its co-enzyme, NAD or NADP and produce NADH or NADPH. The colored formazan dyes are produced upon reduction of NADH in the presence of an electron mediator. To perform the homogenous assay in aqueous condition,  Water-Soluble Tetrazolium salts (WST) are widely applied for the diagnostic analysis and life science research due to much improved water-solubility than water insoluble tetrazolium salts, such like NBT and INT.

Detection Principle

Items Principle (Oxidase System) New Trinder’s Reagents Principle (Dehydrogenase System) Tetrazolium Salts and Electron Mediators
Lactic acid
NH3 -
Uric acid -

2. Chelate Complexes Detection

(1) Other Chromogens for Clinical Chemical Assays

Dojindo offers wide range of reagents that form chelate complex with the target substance in biological sample. These reagents are applicable for quantitative determination of the target substance in the sample.

Items Reagent Principle


Ca2+ + Chlorophosphonazo-III → Ca2+ - Chlorophosphonazo-III complex


Celuroplasmin – Cu2+ → Denaturation → Cu2+ → Reduction → Cu+  + 3,5-DiBr-PAESA → Cu+ - 3,5-DiBr-PAESA complex


Transferrin – Fe3+ → Denaturation → Fe3+ → Reduction→ Fe2+  + Nitroso-PSAP → Fe2+ - Nitroso-PSAP complex

XB-I (Xylidyl blue-I)

Mg2+  + Xylidyl blue-I → Mg2+ - Xylidyl blue-I  complex
Urinary Total Protein

PR (Pyrogallol Red)

Pyrogallol Red  + Molybdate(VI) + Protein → PR – MO - Protein  complex


Physiological Ligand – Zn2+ → Denaturation → Zn2+ + 5-Br-PAPS → Zn2+ - 5-Br-PAPS complex


Zn2+  + Nitro-PAPS → Zn2+ –  Nitro-PAPS  complex

Oxidative Dyes (New Trinder’s Reagents )

Code# Description CAS#
OC01 ADOS 82692-96-4
OC02 ADPS 82611-88-9
OC04 ALPS 82611-85-6
OC06 DAOS 83777-30-4
OC08 HDAOS 82692-88-4
OC11 MAOS 82692-97-5
OC13 TOOS 82692-93-1
OC14 TOPS 40567-80-4
OC21 MADB 209518-16-1
OC22 TODB 1044537-70-3

Reductive Dyes (Tetrazolium Salts )

Code# Description CAS#
W201 WST-1 150849-52-8
W202 WST-3 515111-36-1
W203 WST-4 178925-54-7
W204 WST-5 178925-55-8
W217 WST-9 -
I003 INT 146-68-9
M009 MTT 298-93-1
N011 Nitro-TB 298-83-9
T012 TB 1871-22-3

Oxidative Dyes (Others)

Code# Description CAS#
K257 KN-304 -
D006 DAB 7411-49-6
S302 SAT-3 679787-07-6
T022 TMBZ 54827-17-7
T036 TMBZ-PS 102062-46-4,
102062-36-2(free acid)

Electron Mediators

Code# Description CAS#
M003 1-Methoxy PMS 65162-13-2
M470 1-Methoxy PES 133395-54-7

Chromogens for Chelate Complexes Detection

Code# Description CAS#
C010 Chlorophosphonazo-III 1914-99-4
D041 3,5-DiBr-PAESA 100743-65-5
N010 Nitroso-PSAP 80459-15-0
X001 XB-I 14936-97-1
P012 PR 32638-88-3
B026 5-Br-PAPS 81608-06-2(free acid)
N031 Nitro-PAPS 143205-66-7(as anhydride)


Code# Description CAS#
G213 Glupa-C 63699-78-5
L005 L-Leucyl-p-nitroanilide HCl 16010-98-3
N055 Disodium p-Nitrophenylphosphate 333338-18-4(hexahydrate)