Objective To establish a HPLC-MS/MS method was to for detecting TNT in surface soil. Method The liquid-liquid extraction method was used to extract the analytes. The extraction solvents and mobile phase were optimized, together with both the atmospheric-pressure chemical ionization (APCI) interface and electrospray ionization (ESI) interface for quantitative analysis. The determination was performed by triple quadrupole mass spectrometry operated with a negative APCI interface in the multiple reaction monitoring (MRM) mode. The mass-to-charge ratio (m/z) of 226.9/209.9 was found as the quantiifcation ion pair and m/z 226.9/197.0 as the conifrmation ion pair. Acetonitrile was selected as the extraction solvent. The separation was performed on a Waters Xbrige C18 column (5μm,100 mm×2.1 mm) run with the mixture of methanol and water (65:35) as the mobile phase. Results The ionization efifciency in ESI mode was lower than that in APCI mode. The limit of detection was 0.05ng/g in ESI mode for TNT in surface soil, and the limit of quantitation was 0.05 ng/g . High recovery (88.5%~96.1%) was achieved. Good linearity (R=0.9991) was obtained at the concentration among 0.05~100 ng/g. Matrix effect was 93.7%of liquid-liquid extraction with acetonitrile. Conclusion This method is simple, accurate and sensitive, able to be used for trace TNT detection in explosive residues.%目的：建立液相色谱串联质谱联用仪检验浮土中TNT的方法。方法本文以乙腈作为溶剂提取浮土中的TNT；用Waters Xbrige C18液相色谱柱（5μm，100 mm×2.1 mm），流动相为甲醇꞉水=65꞉35进行样品分离；在APCI源负离子模式下，以m/z226.9/209.9作为定量离子对、m/z226.9/197.0作为定性离子对，用三重四级杆串联质谱进行多反应监测（MRM）分析。结果在ESI源下，TNT的电离效率相对APCI源较低，浮土中TNT的定量限为1ng/g。该方法检测TNT的线性范围为0.05～100 ng/g，相关系数为0.9991，定量下限为0.05 ng/g，加标回收率为88.5%～96.1%，浮土样品采用乙腈提取的基质效应为93.7%。结论本方法操作简单、提取方便，有效避免了尘土复杂基质的干扰，结果准确可靠，灵敏度高，满足对爆炸残留物中TNT的检测要求。
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