p-Nitrophenol Indicator (AR)

p-Nitrophenol Indicator AR

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CHEMICAL IDENTITY

Chemical Name: 4-Nitrophenol

IUPAC Name: 4-Nitrophenol

Chemical Formula: C₆H₅NO₃

Molecular Weight: 139.11 g/mol

CAS Number: 100-02-7

Grade: AR (Analytical Reagent)

Appearance: Yellow Crystalline Compound / Indicator Solution

Manufacturer: Loba Chemie Pvt. Ltd.

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PRODUCT DESCRIPTION

p-Nitrophenol Indicator is a high-purity analytical reagent used as an acid-base indicator, spectrophotometric standard, enzymatic assay substrate product, and analytical chemistry reagent.

The compound exhibits a distinct color transition based on pH and is widely employed in biochemical, pharmaceutical, environmental, and analytical laboratories.

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CHEMICAL STRUCTURE

Molecular Formula:

C₆H₅NO₃

Functional Groups:

• Phenolic Hydroxyl Group (–OH)
• Nitro Group (–NO₂)
• Aromatic Benzene Ring

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INDICATOR PROPERTIES

pKa: ~7.15

Acidic Form:
Colorless to Pale Yellow

Alkaline Form:
Bright Yellow

Indicator Range:
pH 5.4 – 7.5

UV Absorption:
Strong Absorbance Near 400 nm

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COLOR TRANSITION

Acidic Medium

p-Nitrophenol (HIn)

↓

Colorless / Pale Yellow

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Alkaline Medium

p-Nitrophenolate Ion (In⁻)

↓

Intense Yellow

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ANALYTICAL CHEMISTRY APPLICATIONS

• Acid-Base Titrations
• Buffer Preparation Studies
• pH Monitoring Systems
• UV-Visible Calibration Work
• Absorbance Measurements
• Quantitative Analytical Methods
• Water Quality Assessment
• Phenolic Compound Monitoring

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BIOCHEMISTRY APPLICATIONS

p-Nitrophenol is frequently encountered as the colored reaction product generated from enzymatic hydrolysis of synthetic substrates such as:

• p-Nitrophenyl Phosphate (pNPP)
• p-Nitrophenyl β-D-Glucopyranoside
• p-Nitrophenyl Acetate
• p-Nitrophenyl Palmitate

The liberated p-Nitrophenol is quantified spectrophotometrically at:

λmax ≈ 405 nm

making it a valuable reporter molecule in enzyme assays.

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PHARMACEUTICAL APPLICATIONS

• Enzyme Activity Assays
• Drug Metabolism Studies
• Biochemical Screening Procedures
• Analytical Method Development
• Quality Control Testing

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LABORATORY APPLICATIONS

Analytical Chemistry
• Indicator Reagent

Biochemistry
• Enzyme Assay Product

Pharmaceutical Analysis
• Spectrophotometric Testing

Environmental Science
• Water Analysis

Research Laboratories
• Colorimetric Investigations

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PHYSICAL & CHEMICAL PROPERTIES

Physical State:
Crystalline Solid

Color:
Yellow

Odor:
Slight Phenolic Odor

Water Solubility:
Slightly Soluble

Alcohol Solubility:
Soluble

Light Sensitivity:
Moderate

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SAFETY INFORMATION

Hazards:

• Skin Irritant
• Eye Irritant
• Harmful if Inhaled
• Toxic if Swallowed

GHS Classification:

• Acute Toxicity
• Irritant
• Environmental Hazard

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SAFETY PRECAUTIONS

• Wear gloves, laboratory coat, and eye protection
• Avoid inhalation of dust or vapors
• Handle in a well-ventilated laboratory
• Prevent environmental release
• Wash thoroughly after handling

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STORAGE CONDITIONS

Temperature:
Room Temperature

Container:
Tightly Closed

Moisture:
Protect from Humidity

Light:
Store Away from Direct Sunlight

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ASSOCIATED REAGENTS

• p-Nitrophenyl Phosphate (pNPP)
• Tris Buffer
• Sodium Hydroxide
• Potassium Phosphate Buffer
• β-Glucosidase Substrates
• Alkaline Phosphatase Assay Reagents

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PACKAGING

Supplied in amber laboratory reagent bottles designed to protect the indicator from excessive light exposure and maintain long-term stability.

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WLS QUALITY NOTE

p-Nitrophenol Indicator AR is a valuable analytical and biochemical reagent offering reliable pH-responsive color development and spectrophotometric detection for research, educational, pharmaceutical, and industrial laboratory applications.