Inductively Coupled Plasma Mass Spectrometry (ICP-MS) based immunoassay method has been proposed in multiple immunoassays but has not been used in competitive and sandwich formats immunoassay simultaneously. The two immunoassays were usually conducted separately in clinical field depending on the size and the amount of binding sites of targets. We proposed an immunoassay method based on magnetic beads and ICP-MS detection that could be suitable for both small and large molecules. The functionalized magnetic beads were added to capture the immune complex after immune reaction. In this way, thyrotropin and free thyroid hormone can be captured, separated and then detected according to the elemental tags by ICP-MS simultaneously. The new method was evaluated by comparing the results with time resolved fluorescence immunoassays (TRFIA). The dynamic ranges of TSH and FT₄ were 0.16–105 mU/L and 3.5–65 pmol/L, respectively. The limits of detections were 0.06 mU/L for TSH and 1.59 pmol/L for FT₄. And the relative standard deviations (RSD) of TSH and FT₄ were 4.64% at 2.5 mU/L and 1.87% at 5.85 pmol/L. This immunoassay method enables the determination of small and large biomolecules simultaneously via competitive and sandwich immunoassay formats.

基于电感耦合等离子体质谱法（ICP-MS）的免疫测定方法已在多种免疫测定中提出，但尚未同时用于竞争性和夹心形式的免疫测定中。两种免疫测定法通常根据靶标结合位点的大小和数量在临床领域中分别进行。我们提出了一种基于磁珠和ICP-MS检测的免疫分析方法，该方法可能适用于大分子和小分子。加入功能化的磁珠以在免疫反应后捕获免疫复合物。这样，可以同时通过ICP-MS根据元素标签捕获，分离和检测促甲状腺激素和游离甲状腺激素。通过将结果与时间分辨荧光免疫分析（TRFIA）进行比较，对新方法进行了评估。_4个分别为0.16-105 mU / L和3.5-65 pmol / L。检测限为0.06亩/ L为TSH和1.59皮摩尔/ L为FT ₄。TSH和FT ₄的相对标准偏差（RSD）在2.5 mU / L时为4.64％，在5.85 pmol / L时为1.87％。这种免疫测定方法能够通过竞争性和夹心免疫测定形式同时测定大小生物分子。