checks.

2. Scope

This SOP applies to all UV-Visible spectrophotometers used in the Analytical Method Development department of pharmaceutical API and formulation units.

3. Responsibilities

• Analytical Instrumentation Chemist: Performs calibration as per schedule and documents all results.
• QA Officer: Reviews calibration data and ensures compliance to specification.
• Head – AMD: Authorizes final calibration status and usage clearance.

4. Accountability

The Head of Analytical Method Development is accountable for implementation, documentation, review, and verification of spectrophotometer calibration programs.

5. Procedure

5.1 General Calibration Requirements

1. Calibrate monthly or after instrument maintenance, relocation, or repairs.
2. Use certified reference materials (CRM) or traceable calibration standards.
3. Environmental conditions (temperature, humidity) must comply with equipment specifications.

5.2 Wavelength Accuracy Check

1. Use Holmium Perchlorate solution or Didymium filters.
2. Scan the solution or filter in the 200–700 nm range.
3. Confirm that peak positions match certified values within ±1 nm.

5.3 Photometric Accuracy

1. Prepare potassium dichromate solution at concentrations of 60, 40, and 20 ppm.
2. Measure absorbance at 235, 257, 313, and 350 nm.
3. Compare observed absorbance with theoretical values (±0.01 AU acceptable deviation).

5.4 Stray Light Test

1. Use 1.2% potassium chloride solution in a quartz cell.
2. Scan the solution and ensure absorbance at 200 nm is ≥ 2.0 AU.
3. This confirms negligible stray light interference at low wavelengths.

5.5 Resolution Power Check

1. Scan 0.02% toluene in hexane between 260–280 nm.
2. Ensure ratio of absorbance at 269 nm to 266 nm is ≥ 1.5 (US FDA and USP requirement).

5.6 Baseline Flatness and Noise

1. Run baseline scan using air or blank quartz cells from 200 to 800 nm.
2. Ensure deviation is within ±0.01 AU and noise is below acceptable limit (usually ±0.002 AU).

5.7 Documentation and Labeling

1. Record calibration results in the Calibration Logbook (Annexure-1).
2. Label instrument with status tag (CALIBRATED/OUT OF CALIBRATION).
3. Retain calibration reports for minimum 3 years or as per regulatory requirement.

6. Abbreviations

• AU: Absorbance Unit
• nm: Nanometers
• CRM: Certified Reference Material
• QA: Quality Assurance

7. Documents

1. Annexure-1: UV-Visible Spectrophotometer Calibration Log
2. Annexure-2: Monthly Calibration Schedule

8. References

• USP <857> – Ultraviolet-Visible Spectroscopy
• ICH Q2(R1) – Validation of Analytical Procedures
• FDA Guidance for Analytical Procedures and Methods Validation

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Saurabh Mehta	Meena Nair	Dr. Anil Dubey
Designation	Instrument Chemist	QA Reviewer	Head – AMD
Department	Analytical Method Development	Quality Assurance	Analytical Method Development

11. Annexures

Annexure-1: UV-Visible Spectrophotometer Calibration Log

Date	Parameter	Observed Value	Specification	Status
01/06/2025	Wavelength Accuracy	±0.7 nm	±1.0 nm	Pass
01/06/2025	Photometric Accuracy	0.001 AU deviation	±0.01 AU	Pass
01/06/2025	Stray Light	2.3 AU	≥2.0 AU	Pass

Annexure-2: Monthly Calibration Schedule

Lists all spectrophotometers by instrument ID with due dates and completion dates. Updated by instrumentation coordinator monthly.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
01/06/2025	2.0	Included baseline flatness and stray light tests	Annual Review	Dr. Anil Dubey
01/06/2022	1.0	Initial release	New SOP	QA Head