Abstract: Objective To establish a method of analysing of basic dyes in blue ballpoint pen ink by liquid chromatography tan-dem mass spectrometry for the discrimination of blue ballpoint pen ink on a questioned document. Methods Specific precursor and product ion pairs of crystal violet,methyl violet, victoria blue B, basic violet 14, basic blue 7 and rhodamine B were deter-mined by a triple quadrupole tandem mass spectrometer.Ink lines of fifty blue ballpoint pens were drawn on one piece of print paper. Four hole punches of each ink sample were collected with a Harris MICRO-PUNCH (0.5 mm i.d.). Acetonitrile was added to perform extraction in an ultrasonic water bath. Waters XBridge C18 column was used for separation.Target compounds were eluted by a gradient procedure in which O.1% formic acid solution and acetonitrile were used as mobile phase. Results Four hole punches of ink samples provided good signals for the analysis. Intra-batch precision was quite good as the relative standard deviation was no more than 2.3%.Discrimination power of established method was 94.4%. Conclusion The present study provided a precise method for the discrimination of blue ballpoint pen ink on a questioned document. 

Key words: blue ballpoint pen ink, basic dye, LC-MS/MS, discrimination

摘要： 目的 建立蓝色圆珠笔油墨中碱性染料的LC-MS/MS方法.为蓝色圆珠笔油墨的种类鉴别提供方法。方法 用二级质谱寻找并确定结晶紫、甲基紫、维多利亚蓝 B、碱性紫 14、碱性蓝7和罗丹明 B等碱性染料的特征性母离子/子离子对。收集 50种蓝色圆珠笔，划线后对其笔道用 0.5mm 直径打孔器取样，乙腈超声提取。液相分离采用Waters XBridge C8 柱，流动相为0.1%甲酸缓冲液（A）-乙腈（B），梯度程序洗脱。结果 4个点的取样量足以满足检测需要，采用相对峰面积的定量方法，结果重现性好，RSD%≤2.3%。应用该方法对50种蓝色圆珠笔油墨中的碱性染料进行检测，区分率为94.4%。结论 所建 LC-MS/MS方法定性准确，定量可靠，为蓝色圆珠笔油墨的种类鉴别提供了方法。

关键词: 蓝色圆珠笔油墨, 碱性染料, LC-MS/MS, 种类鉴别