Comparison of Separation and Selectivity of Nexera™ Organic Acid Analysis System and Reversed Phase-UV Method

Introduction

Organic acids are organic substances that indicate acidity, and many are ionic compounds containing a carboxyl group. Organic acids are used in a wide range of fields, such as food, chemical, energy, and the environment. In any field, multi-component simultaneous analysis is required. The simplest method for analysis of organic acids by HPLC is reversed phase separation-ultraviolet absorbance detection (reversed phase-UV method). Although analysis can be done using a combination of commonly used ODS column and UV detector, it is not always possible to obtain accurate quantitation results because organic acids generally have high polarity and thus are difficult to retain in ODS column. Furthermore, due to detection in a short wavelength range, the results are also strongly influenced by contaminants depending on the sample. The Shimadzu Nexera organic acid analysis system employs the “post-column pH buffering electric conductivity detection method (post-column method)" in which organic acids are separated using ion exclusion chromatography and then mixed with a pH buffering reagent to enhance detection sensitivity. Moreover, results with excellent repeatability can be obtained easily by using a Shimadzu mobile phase and reagent kit for organic acid analysis, which includes the mobile phase and the pH buffering reagent. In this article, comparative analyses of two different types of samples were conducted using the respective separationdetection methods. As introduced in the following, this experiment demonstrated that highly reliable results were able to be obtained in a short time with reversed phase-UV method depending on the sample, but the high selectivity of the postcolumn method was effective for analysis of diverse samples.

December 10, 2020 GMT