A spectrophotometric procedure for sialic acid determination in milk employing a flow-batch analysis system with direct heating

Autor: Nattany T.G. de Paula, André F. Lavorante, Joicy B. De Souza Costa, Gustavo Souza, Paulo Antonio da Silva, Ana Paula S. Paim
Rok vydání: 2019
Předmět:
Zdroj: Microchemical Journal. 147:782-788
ISSN: 0026-265X
DOI: 10.1016/j.microc.2019.03.086
Popis: The quantitative determination of sialic acid can indicate the addition of cheese whey to milk. This work describes an automated procedure to determine sialic acid in milk samples using a flow-batch system analysis with direct heating. The sialic acid quantification was based on a reaction between the sialic acid and acid ninhydrin producing a stable compound with maximum absorption at 470 nm. The flow-batch system was designed using heating and spectrophotometric detection in the reaction chamber. Under the optimum experimental conditions, a linear response ranging from 1.0 to 10.0 mg L−1 sialic acid (R = 0.99 and n = 7), a detection (3σ criterion) and quantification (10σ criterion) limit estimated at 0.239 and 0.726 mg L−1, respectively, a relative standard deviation of 1.90% (n = 10) for a reference solution of 4.0 mg L−1 sialic acid and a sampling rate of 7 determinations per hour were achieved. Analysis of eleven milk samples, application of the t-test to the results found, and comparison with the official method provided no significant differences at a 95% confidence level. Compared to the official method, the proposed system reduced reaction time by 50%, temperature of the reaction by 30%, and diminished the consumption of reagents and samples by 90%. Thus, the use of the proposed system is an economically viable and environmentally friendly option for the determination of sialic acid in milk.
Databáze: OpenAIRE
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