A modified Winkler's method for determination of dissolved oxygen concentration in water: Dependence of method accuracy on sample volume. (August 2017)

• Record Type: Journal Article
• Authors: Shriwastav, Amritanshu; Sudarsan, Guttapati; Bose, Purnendu; Tare, Vinod
• Is Part Of: Measurement. Volume 106(2017)
• Page Start: 190
• Page End: 195
• Publication Date: 2017-08
• Subjects: Winkler's method -- Dissolved oxygen -- Functional relationship estimation by maximum likelihood -- Statistical analysis; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2017.05.004
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: A micro Winkler method is developed for dissolved oxygen determination. DO measurements in 7 mL samples are similar to 200 mL in Winkler's method. Proposed method is a suitable alternative for standard Winkler's method. This is particularly useful when sample volume is limited. Abstract: A modification to the standard Winkler's method (WM) for measurement of dissolved oxygen (DO) concentration in aqueous samples enabled DO measurements in 1 mL sample volume. However, advanced statistical analysis indicated that the proposed method (PM) showed a small positive bias, giving results that were on average about 6% higher than corresponding values measured using the WM. In this study, DO measurements were carried out in sample volumes ranging from 2 mL to 10 mL using the PM. Statistical analysis of these results indicate that the bias reported in the PM could be eliminated (i.e., limited to a ± 2% range) using sample volumes of 7 mL or higher. Use of a larger sample volume also enables lowering the least count of the PM to 0.1 mg/L O2 as compared to 0.25 mg/L O2 reported previously.