Determination of Four Organotin Compounds in Poly(Lactic Acid) Materials by ASE-HPLC-ICP-MS

A method was developed for the determination of four organotin compounds including dibutyltin(DBT), triphenyltin(TPhT), tributyltin(TBT) and dioctyltin(DOT) in poly(lactic acid) materials by accelerated solvent extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometer(ASE-HPLC-ICP-MS). The crushed samples were extracted for 10 min under 120 ℃ by ASE， methanol-water-acetic acid mixture（65∶23∶12，V/V/V） as the extraction solvent. The filtered extract was eluted on Agilent TC-C18 column using the mobile phase of methanol and 35% acetic acid aqueous solution(3.0% triethylamine) gradient elution, which was determined by ICP-MS. The mass concentration of organotin compounds has a linear range of 1—100 μg/L for DBT, TPhT and TBT, 3—300 μg/L for DOT with good correlation coefficients (r²≥0.999). The limits of quantitation (LOQs) are 30.0, 33.3, 55.0, 101.7 μg/kg for DBT, TPhT, TBT and DOT, respectively. The average spiked recoveries are 82.7%—88.4%， 89.5%—91.5%， 91.6%—103.5% at the level of LOQ, five times the LOQ and the limit values of Oeko-tex Standard 100， respectively, with the relative standard deviations(RSDs) of 4.3%—7.8%. The method is simple, effective, reliable and highly sensitive, which can meet the requirements of the domestic and international legislations，and can be used to determine organotin residues in poly(lactic acid) materials.