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A Simplified Method for Measurement of Lactic Acid and Sulfur Dioxide in Corn Wet Milling Steep Water
Author(s) -
Shandera Donald L.,
Jackson David S.
Publication year - 1993
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19930451005
Subject(s) - lactic acid , sulfur dioxide , sulfur , chemistry , chromatography , high performance liquid chromatography , carbon dioxide , organic chemistry , geology , bacteria , paleontology
A rapid HPLC method for measurement of lactic acid in corn wet milling steep water was developed. This technique is also suitable for simultaneous analysis of sulfur dioxide (sulfurous acid). Lactic acid and sulfur dioxide were analyzed using a Shodex Ionpak KC‐811 HPLC column with a Waters 410 refractive index detector within 11 min. In preparing steep water for laboratory batch steeps, lactic acid from 85% syrup must be diluted to 10% (w/w) and heated at 95°C for 24 h to obtain free lactic acid. Steep water solubles, developed as steep time increases, did not interfere with the analysis. Duplicated injections (64) of steep water gave an average coefficient of variation of less than 4% between duplicates for both lactic acid and sulfur dioxide. Coefficients of variation for pure sulfur dioxide and lactic acid solutions were less (2.2% and 0.2%, respectively). This HPLC method is rapid, precise, and suitable for automation.