中文摘要：

首先建立了液相色谱法与液相色谱-电感耦合等离子质谱法测定牛乳中不同价态铬的方法。液相色谱法采用Ion Pac CG5A分析柱分离,PDC柱后衍生,紫外检测器测定不同价态铬质量浓度,当进样量为100μL时,对溶液中最低检出质量浓度[Cr（Ⅲ）]与Cr（Ⅵ）[Cr（Ⅵ）]分别为10.0μg/L与1.0μg/L;液相色谱-电感耦合等离子质谱法使用Ion Pac AG11阴离子交换色谱柱、NH4NO3淋洗液,可以很好地分离溶液中的Cr（Ⅲ）[Cr（Ⅲ）]和Cr（Ⅵ）[Cr（Ⅵ）],当进样量为100μL时,对溶液中最低检出质量浓度[Cr（Ⅲ）]与Cr（Ⅵ）[Cr（Ⅵ）]分别为0.25μg/L与0.03μg/L。通过在牛乳中添加不同浓度的Cr（Ⅵ）后测定Cr（Ⅲ）和Cr（Ⅵ）,证明部分Cr（Ⅵ）可转化为Cr（Ⅲ）。通过分析认为因牛乳中存在一定量的还原物质而将Cr（Ⅵ）还原为Cr（Ⅲ）所致。当Cr（Ⅵ）添加量在0.8 mg/L以下时检测不出Cr（Ⅵ）,说明当牛乳中铬的含量在国家规定的限量值（0.3 mg/L）以下时全部以Cr（Ⅲ）存在;即使铬质量浓度达到0.8 mg/L时,其对人体的危害风险仍较小（一定量的Cr（Ⅲ）对人体是有益的）,都属于安全质量浓度范围。

英文摘要：

the method was established for determination of different valence chromium in milk with liquid chromatography and liquid chromatography- Inductively coupled plasma mass spectrometry. HPLC method using Ion Pac CG5 A analytical column for separation and post column derivatization, PDC, determination of different valence chromium content of UV detector, when the amount of sample is 100μL,the minimum detectable concentration of solution of [Cr（Ⅲ）] and [Cr（Ⅵ）] were 10μg/L and 1μg/L; HPLC-ICP-MS method using IonPac AG11 anion exchange column, NH4NO3 leaching solution, can be well separated in solution of trivalent chromium（Ⅲ） [Cr] and six chromium（Ⅵ） [Cr], when the amount of sample is 100 L, the minimum detectable concentration of solution [Cr（Ⅲ）] and [Cr（Ⅵ）] were0.25μg/L and 0.03μg/L. Determination of [Cr（Ⅲ）] and [Cr（Ⅵ）] by adding different concentration [Cr（Ⅵ）] in milk, prove part [Cr（Ⅵ）]into [Cr（Ⅲ）]. Through the analysis that should be there is a certain amount of reducing substances in milk and [Cr（Ⅵ）] reduction to [Cr（Ⅲ）] induced. When the [Cr（Ⅵ）] addition amount below 0.8 mg/L detected [Cr（Ⅵ）], that when the content of chromium in milk in the limited value of the provisions of the state（0.3 mg/L） below all exists in [Cr（Ⅲ）]; even if the chromium content reached 0.8 mg/L, its harm to human body of risk is still small（t [Cr（Ⅲ）] amount is beneficial to human body）, all belong to the safety range of content.