Method of analysis of hydraulic cement by atomic absorption spectrophotometer

IS 12813 - Scope & Key Specifications

Scope (Clause 1.2)

• Covers determination of oxides:
  SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO, Na₂O, K₂O, Mn₂O₃, TiO₂, Cr₂O₃
• Compositions expressed as % oxides but determined as % elements.
• Related IS standards for reagents and sampling are essential adjuncts (IS 264, 266, 1070, 3535, 4032).

Sample Preparation & Dilutions (Clauses 10.1.2 & 11.1)

Instrument Settings (Clause 12.1)

• Adjust spectrophotometer as per manufacturer.
• Use Table 3 (not provided here) for working ranges & standard conditions.

Summary Flow of Analysis Preparation

flowchart TD
    A[Sample Collection] --> B[Preparation of Sample Solution]
    B --> C[Dilution as per Table 1 & 2]
    C --> D[Instrument Setup & Calibration]
    D --> E[Measurement & Analysis]
    E --> F

IS 12813 Key References: Sample Preparation & Calculation

1. Sample Preparation (Clause 10.1.2 & 11.1)

• Use Table 1 for standard sample dilutions.
• Use Table 2 for unknown sample analysis dilutions.

2. Percent Oxide Calculation (Clause 13.1)

[ \text{Percent Oxide} = \frac{X \times Y \times DF \times Z \times 10^{-4}}{M} ]

Where:

Conversion Factors (Z):

IS 12813: Sampling - Key Formulas & Tables

1. Sample Solution Preparation (Clause 10.1.2)

Typical dilutions for calibration standards:

2. Sample Solution for Unknowns (Clause 11.1)

IS 12813 – Outline of the Method: Key Formulas, Tables & Specifications

1. Scope (Clause 1.2)

• Determines SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O, K2O, Mn2O3, TiO2, Cr2O3.
• Results expressed as % oxides, but analysis done on elemental basis.

2. Sample Preparation (Clauses 10.1.2 & 11.1)

Refer to Tables 1 & 2 for detailed dilution volumes for calibration and unknown samples.

3. Calculation of Percent Oxide (Clause 13.1)

[ \text{Percent Oxide} = \frac{X \times Y \times DF \times Z \times 10^{-4}}{M} ]

Where:

IS 12813: Safety Precautions for Atomic Absorption Analysis

Key Safety Points (Clause 5.1)

• Follow manufacturer instructions strictly for igniting/extinguishing the burner to prevent explosions and injuries.
• Use proper PPE (gloves, goggles) when handling Lithium metaborate and nitric acid.
• Work in a well-ventilated area or fume hood due to toxic fumes during fusion and dissolution.

Sample Preparation & Dilution (Clauses 10.1.2 & 11.1)

Refer to Table 1 & 2 for detailed dilution steps.

Calibration Curve Preparation (Clause 4.2)

• Fuse sample with Lithium metaborate.
• Dissolve bead in dilute nitric acid.
• Prepare standard solutions from reference materials.
• Measure absorbance and plot Absorbance vs Concentration.
• Use calibration curve to find unknown concentrations.

Summary Diagram: Sample Preparation Workflow

flowchart TD
    A[Fusion with Lithium Metaborate] --> B[Dissolution in Dilute Nitric Acid]
    B --> C[Prepare Standard Solutions]
    C --> D[Measure Absorbance]
    D --> E[Plot Calibration Curve]
    E --> F[Determine Unknown Concentration]

**Always prioritize safety by following manufacturer instructions

Reproducibility of Results in IS 12813 relates to precise preparation and dilution of sample and standard solutions for atomic absorption spectrophotometry calibration.

Key Tables for Dilution & Calibration

Important Specifications & Notes:

• Precision improves by selecting standard samples close to the unknown sample concentration.
• Linearity range can be extended by adjusting burner path length.
• Use internal standard elements (not present in sample) for absorbance ratio to eliminate dilution errors.
• For Ca and Mg standards, add 0.1% lanthanum or strontium to avoid interference.

Formula for Dilution Factor (DF):

[ DF = \frac{\text{Final volume}}{\text{Volume of sample or standard solution}} ]

Summary Flow of Sample Preparation for Reproducibility:

IS 12813: Apparatus and Equipment - Key Formulas, Tables, and Specifications

1. Sample Preparation Equipment (Clause 7.3)

• Equipment must ensure consistent, representative samples for analysis.
• Follow manufacturer instructions for operation and calibration.

2. Instrument Settings (Clause 12.1)

• Adjust spectrophotometer settings per manufacturer guidelines.
• Use Table 3 (not provided here) for standard working ranges and parameters for elements.

3. Sample Solution Preparation (Clause 10.1.2 & 11.1)

Table 1: Typical Dilutions for Standard Samples (Excerpt)

Table 2: Dilutions for Unknown Samples (Clause 11.1)

| Oxide | Approx % Constituent | Sample Solution C (ml) | Make up to (ml) | Blank Solution B (ml) | Make up to (ml)

IS 12813: Key Formulas, Tables & Specifications for Reagents and Standard Solutions

1. Standard Solutions for Major Constituents (Clause 10.1)

• Preparation involves dilution of stock solutions (Solution 'A', 'B', 'C') to achieve desired concentration.
• Typical constituents: SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO, Na₂O, K₂O, MnO, TiO₂, Cr₂O₃.

2. Table 1: Typical Dilutions for Standard Samples (Clause 10.1.2)

3. Table 2: Dilutions for Sample Solutions (Clause 11.1)

| Oxide | Approx % Constituent | ml Solution 'C' | Make up to (ml) | ml Solution 'B' | Make up to (ml) | |-------|---------------------|-----------------|-----------------|

IS 12813 Calibration Key Points

Calibration Procedure (Clauses 12.1.1 & 12.1.2)

• Aspirate blank solution, then standard solutions sequentially.
• Record average absorbance for each known concentration.
• Use 5 standard solutions for precise calibration; 3 for routine.
• After standards, aspirate blank and sample; check blank drift.

Sample Preparation & Linearity (Table 1, Clause 10.1.2)

General Calibration Formula

[ \text{Concentration} = \frac{(A_s - A_b)}{(A_{std} - A_b)} \times C_{std} ]

• (A_s): Absorbance of sample
• (A_b): Absorbance of blank
• (A_{std}): Absorbance of standard
• (C_{std}): Concentration of standard

flowchart TD
    Blank --> Std1 --> Blank --> Std2 --> Blank --> ... --> StdN --> Blank --> Sample
    Std1[Standard Solution 1]
    StdN[Standard Solution N (3 or 5)]

Summary:

IS 12813 — Preparation of Sample Solutions: Key Tables & Specifications

1. Sample Solution Dilutions (Clause 11.1, Table 2)

2. Standard Sample Dilutions for Calibration (Clause 10.1.2, Table 1)

IS 12813: Preparation of Standard and Blank Solutions

Key Tables for Dilutions

Table 1: Standard Sample Dilutions (Clause 10.1.2)

Table 2: Sample and Blank Solution Dilutions (Clause 11.1)

IS 12813 - Atomic Absorption Spectrophotometric Analysis: Key Points

1. Principle (Clause 4.1)

• Sample solution aspirated into flame.
• Radiation from element-specific hollow cathode lamp passes through flame.
• Absorption ∝ concentration of neutral atoms.
• Concentration determined by comparing absorbance to calibration curve.

2. Instrumentation (Clause 7.4.1)

• Atomizer/Burner: Maintains constant oxidant & fuel pressure.
• Light Source: Hollow cathode lamp or electrode-less discharge lamp.
• Detector: Photomultiplier tube.
• System: Amplifier and read-out for absorbed radiation measurement.

3. Sample Preparation (Clause 4.2)

• Fuse sample with Lithium metaborate.
• Dissolve fused bead in dilute nitric acid.
• Dilute to optimum concentration for analysis.
• Prepare calibration standards from reference materials.
• Plot absorbance vs. concentration → calibration curve.

4. Calibration Curve Equation

[ A = \varepsilon \cdot b \cdot c ]

• (A): Absorbance
• (\varepsilon): Molar absorptivity (constant)
• (b): Path length (cm)
• (c): Concentration of analyte

5. Safety (Clause 5)

• Handle acids and flame carefully.
• Maintain gas pressure controls.
• Use protective equipment.

flowchart LR
    Sample --> Fusion[Sample fusion with Li-metaborate]
    Fusion --> Dissolution[Dissolve in dilute HNO3]
    Dissolution --> Dilution[Dilute to optimum concentration]
    Dilution --> AAS[Atomic Absorption Spectrophotometer]
    AAS --> Calibration[Calibration curve from standards]
    Calibration --> Concentration[Determine unknown concentration]

This summarizes the essentials for atomic absorption spectrophotometric analysis per IS 12813.

IS 12813 Key Formulas & Tables for Calculations

1. Percent Oxide Calculation (Clause 13.1)

[ \text{Percent Oxide} = \frac{X \times Y \times DF \times Z \times 10^{-4}}{M} ]

Where:

• X = pg/ml of element in aspirated sample
• Y = volume of first sample dilution (ml)
• DF = dilution factor (based on aliquot taken)
• Z = conversion factor from element to oxide (see table below)
• M = mass of sample taken (g)

2. Sample Preparation Dilution Tables

• Table 1 (Clause 10.1.2): Typical dilutions for standard samples with approximate % constituent, volumes for dilution, and linearity ppm ranges.
• Table 2 (Clause 11.1): Dilutions for unknown samples, specifying volumes of solutions 'B' and 'C' for analysis and blanks.

3. Procedure Highlights (Clause 12.1.2)

• Follow manufacturer instructions for aspirating solutions.
• Calibrate with standard solutions.
• Aspirate blank solution to check zero drift.
• Record absorbance/concentration for blank and sample.

This formula and tables ensure accurate oxide % determination from elemental analysis via dilution and calibration steps.

Composition of the Technical Committee (IS 12813 - Annex A)

The Technical Committee for Cement and Concrete (CED 2) includes experts from:

• Chairman: Dr. H. C. Visvesvaraya

• Members: Representatives from key organizations such as:

  • National Council for Cement and Building Materials, New Delhi
  • Larsen and Toubro Limited, Bombay
  • National Test House, Calcutta
  • Bhakra Beas Management Board, Nangal Township
  • Central Public Works Department, New Delhi
  • Irrigation Department, Government of Punjab
  • Central Soil and Materials Research Station, New Delhi
  • Structural Engineering Research Centre (CSIR), Ghaziabad and Madras
  • The India Cements Limited, Madras
  • Research, Designs and Standards Organization (Ministry of Railways), Lucknow
  • Indian Hume Pipes Co Limited, Bombay
  • Indian Roads Congress, New Delhi
  • Central Road Research Institute (CSIR), New Delhi
  • Central Building Research Institute (CSIR), Roorkee
  • Various cement companies, government departments, and research institutions

• Secretary: Shri K. R. Saxena (Central Board of Irrigation and Power, New Delhi)

• Ex-officio Member: Director General, BIS

Key Notes:

• The committee includes chairman, members, alternates, and representatives from government, research, and industry.
• This diverse composition ensures comprehensive expertise in cement and concrete standards development.

Table Extract (Example):

This composition ensures balanced technical inputs from academia, industry, and government bodies for cement and concrete standards under IS 12813.