Startin James R, Hird Simon J, Sykes Mark D
Central Science Laboratory, Sand Hutton, York, UK.
Food Addit Contam. 2005 Mar;22(3):245-50. doi: 10.1080/02652030500110618.
A robust and sensitive method for the determination of ethylenethiourea (ETU) and iso-propylenethiourea (i-PTU) in foods is reported. ETU and i-PTU were extracted by blending with dichloromethane (DCM) in the presence of sodium sulphate, sodium carbonate, thiourea and ascorbic acid. 2H4-ETU and n-PTU were used as internal standards. After filtration the DCM was removed by rotary evaporation and the extract re-dissolved in water before analysis by reversed-phase liquid chromatography with detection by atmospheric pressure chemical ionization-mass spectrometry using a double focusing mass spectrometer at a resolution of 5000. Mean recoveries of ETU and i-PTU from fruit-based, cereal-based and meat-based infant foods, potato chips and tinned potatos at 0.01 mg kg(-1) and from pizza and yoghurt at 0.02-0.1 mg kg(-1) were 95% and 97% respectively. Precision, including both repeatability and internal reproducibility, was in the range of 3.1-13.1%.
报道了一种测定食品中乙撑硫脲（ETU）和异亚丙基硫脲（i-PTU）的稳健且灵敏的方法。在硫酸钠、碳酸钠、硫脲和抗坏血酸存在的情况下，通过与二氯甲烷（DCM）混合来提取ETU和i-PTU。使用2H4-ETU和正丙基硫脲（n-PTU）作为内标。过滤后，通过旋转蒸发除去DCM，提取物在反相液相色谱分析前重新溶解于水中，并使用分辨率为5000的双聚焦质谱仪通过大气压化学电离-质谱进行检测。ETU和i-PTU在0.01 mg kg⁻¹时从水果基、谷物基和肉类基婴儿食品、薯片和罐装马铃薯中的平均回收率，以及在0.02 - 0.1 mg kg⁻¹时从披萨和酸奶中的平均回收率分别为95%和97%。包括重复性和内部再现性在内的精密度在3.1 - 13.1%范围内。
