Aim: This research article develops and validates two analytical methods for the quantitative estimation of ascorbic acid (Vitamin C) in various fruit samples, aiming for high accuracy and compliance with ICH Q2(R1) guidelines. The study employs a combination of direct titrimetric analysis and UV-visible spectrophotometry to measure and compare ascorbic acid content in bulk samples and freshly prepared fruit extracts.

Materials and Methods: The titrimetric method utilizes standardized iodine solution and starch indicator under controlled pH and temperature, enabling accurate endpoint detection and quantification. Additionally, the UV-visible spectrophotometric assay involves the preparation of fruit juices in oxalic acid as stabilizer, with absorbance recorded at 265 nm to prevent oxidation. Method validation was conducted according to ICH Q2(R1) criteria, covering linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). Fruits selected for analysis included lemon, orange, amla, and guava; freshly extracted juices were procured & used for all estimations.

Results: The linear calibration range for UV spectrophotometric analysis was established between 2–14 μg/mL, with a regression coefficient (R²) of 0.999. Accuracy studies using spiked standard addition yielded recovery rates between 95–102%. Precision was confirmed by replicate analysis (RSD < 2%). The titrimetric method demonstrated consistent results across fruit samples, supporting the robustness of endpoint detection. LOD and LOQ values for UV analysis were found to be 0.15 μg/mL and 0.45 μg/mL, respectively, confirming high sensitivity. Among tested fruits, amla and guava exhibited higher concentrations of ascorbic acid compared to citrus fruits. The proposed methods were proven to be rapid, reliable, and suitable for routine quality control and nutritional assessment of fruit-derived ascorbic acid.