称取卷烟烟丝0.200 0 g，用100 mmol·L^-1 EDTA溶液（pH 7.5）20 mL，于50℃水浴中提取3 h；取此提取液5 mL经过炭黑小柱净化，得到烟丝的样品溶液。为制得烟气中粒相物样品溶液，取20支卷烟，经转盘吸烟机用静电捕集法捕集烟气中的粒相物；用上述EDTA溶液将捕集管上的粒相物全部冲洗于20 mL容量瓶中，定容后在相同条件下提取并净化。将在标准抽吸条件下所得一整支卷烟的烟灰和烟蒂，按上述相同条件用EDTA溶液提取后，取提取液5 mL，经0.45 μm滤膜过滤，滤液为烟灰和烟蒂的样品溶液。以上所得3份样品溶液分别收集于离子色谱进样瓶中，用IonPac AG11-HG色谱柱分离，用50 mmol·L^-1硝酸铵溶液（pH 6.8）作为流动相进行洗脱；按所选条件用电感耦合等离子体质谱法测定洗脱液中Cr（Ⅲ）和Cr（Ⅵ）。结果表明：Cr（Ⅲ）与Cr（Ⅵ）的质量浓度分别在0.15~1 500，0.06~600 μg·L^-1内与对应的峰面积之间呈线性关系，检出限（3S/N）分别为0.15，0.06 μg·L^-1。用标准加入法测得方法的回收率依次在95.2%~98.6%，90.6%~96.8%；对同一样品重复进样7次，峰面积的相对标准偏差依次为3.3%，4.8%。结果显示：卷烟中铬的主要来源于烟丝，以Cr（Ⅲ）为主；在抽吸过程中，熔点较低的Cr（Ⅲ）化合物容易转移至烟气的粒相物中，从而被滤嘴截留或进入主流烟气中，而Cr（Ⅵ）则大部分残留在烟灰中。

A portion (0.200 0 g) of cut tobacco packed in the cigarette was taken and extracted with 20 mL of 100 mmol·L^-1 EDTA solution (pH 7.5) in a water bath at 50℃ for 3 h; an aliquot (5 mL) of the extract was purified by passing through a microcolumn packed with carbon black. The eluate was taken as the sample solution of cut tobacco. To prepare the sample solution of particulate matter in smoke of cigarette, 20 cigarettes were smoked by a rotary smoking machine, and the particulates in the smoke were collected by static trapping. 20 mL of 100 mmol·L^-1 EDTA solution (pH 7.5) were used to wash down the particulates from the collection tube and transferred to a 20 mL volumetric flask, which was then extracted and purified under the same way as described above. Smoking of a whole cigarette was done under the standard smoking condition, and the cigarette ash and butt obtained were extracted with 20 mL of EDTA solution (pH 7.5) in the same way, and 5 mL of the extract were filtered through 0.45 μm filter membrane and the filtrate was taken as the sample solution of cigarette ash and butt. The 3 sample solutions were then separated respectively by IC using IonPac AG11-HG column as stationary phase and 50 mmol·L^-1 NH₄NO₃ solution (pH 6.8) as mobile phase for elution. Cr(Ⅲ) and Cr(Ⅵ) in the eluate were finally determined by ICP-MS under the prescribed instrumental condition. Linear relationships between values of peak areas and mass concentrations of Cr(Ⅲ) and Cr(Ⅵ) were found in the ranges of 0.15 to 1 500 μg·L^-1 and 0.06 to 600 μg·L^-1, with detection limits (3S/N) of 0.15 μg·L^-1 and 0.06 μg·L^-1, respectively. Test for recovery was carried out by standard addition method, and values of recovery were 95.2%-98.6% for Cr(Ⅲ) and 90.6%-96.8% for Cr(Ⅵ). Precision of the method was tested by replicate determinations on a same sample, values of RSDs (n=7) of the peak areas obtained were 3.3% for Cr(Ⅲ) and 4.8% for Cr(Ⅵ). It was shown that the main source of Cr in cigarettes was the cut tobacco and that the Cr was mainly in its trivalent state. And during smoking, Cr(Ⅲ) compounds were easily transferred into the partioulates of the smoke, due to their relatively low melting point, and either were trapped by the stub-filter or entered into the mainstream smoke; while most of the Cr(Ⅵ) was remained in the ash.