Researchers from Soochow University (Taipei, Taiwan, Republic of China) applied an in-syringe liquid-liquid microextraction technique to prepare a clenbuterol sample for analysis by high performance liquid chromatography (HPLC). The researchers first drew a 10-L volume of formic acid into a 100-L syringe and then a 20-L volume of a sedimented sample containing the drug. Repeated cycling of the plunger in and out enabled extraction of the drug into the aqueous formic acid phase. They then used reversed-phase HPLC with a C18 column and an aqueous acetonitrile mobile phase to analyze the extract.