High Speed Analysis of Anionic Surfactants

Introduction

In the quantification of anionic surfactants in tap water, standard solution containing various branched types of C10 to C14 are analyzed and about twenty peaks obtained are classified by carbon number. Each sum of peak areas from identical carbon chain number is then used for quantification. Separation columns for anionic surfactants can be categorized into (1) columns that afford multiple peaks by the recognition of the branched chains for each carbon number and (2) columns that do not recognize branched chains by carbon number and thus afford only a single peak for ezch carbon number. According to the Ministerial Ordinance on Water Quality Standards, solid phase extraction-high performance liquid chromatography has been adopted as the test method for anionic surfactants and the reference value is 0.2 mg/L as the total for 5 classified carbon chain groups. For this test method, a Ministerial Ordinance specifies “a stainless steel column having an internal diameter of 4.6 mm and a length of 15 to 25 cm, packed with silica gel having a particle size of 3 to 5μm chemically bonding an octadecyl silyl base, or a column having separation performance equal or superior thereto”. The column specified in this Ordinance is classified as the above- mentioned (1) type of column. In Application News No. L477B, a Shim-pack^TM VP-ODS (internal diameter: 4.6 mm, length: 25 cm, particle size: 5 μm) was used. The present article introduces an application using a Shim-pack FC-ODS (internal diameter: 4.6 mm, length: 15 cm, particle size: 3 μm). High speed analysis using a Shim-pack XR-ODS (internal diameter: 3.0 mm, length: 10 cm, particle size: 2.2 μm) is also introduced.

June 14, 2019 GMT