The reference values of linear alkylbenzene sulfonic acid (LAS) and linear alkylbenzene sulfonate have been set in 2013 in Japan. Since LAS has different branched structures even for alkyl chains of the same length, isomer separation occurs in general ODS column, making it difficult to quantify. RSpak DE-213, a polymer-based column for reversed-phase chromatography, is suitable for separation and quantification for each alkyl chain because isomers are eluted without separating isomers. Furthermore, when using DE-213, the analysis is completed within 5 minutes with isocratic conditions, so it is also useful for high-throughput analysis of many samples.


Sample : 5 μL
Sodium p-n-octylbenzenesulfonate (C=8) 50 ng/mL
Sodium decylbenzenesulfonate (C=10) 5 ng/mL
Sodium undecylbenzenesulfonate (C=11) 5 ng/mL
Sodium dodecylbenzenesulfonat (C=12) 5 ng/mL
Sodium tridecylbenzenesulfonate (C=13) 5 ng/mL
Sodium tetradecylbenzenesulfonate (C=14) 5 ng/mL
(in H₂O/CH₃CN=1/1)

Column       : Shodex RSpak DE-213 (2.0 mm I.D. x 150 mm)
Eluent       : (A) 50 mM HCOONH4 + 0.1 % HCOOH aq./(B) CH3CN 
               Isocratic; (B %) 55 %
Flow rate    : 0.2 mL/min 
Detector     : ESI-MS (MRM Negative) 
Column temp. : 40 °C