An internal standard correction–high-performance liquid chromatography–quantitative nuclear magnetic resonance (ISC–HPLC–qNMR) procedure was established as a reliable quantitative method for complex organic compounds with low purity in order to solve the risk of qNMR inaccuracy because of insufficient resolution of impurity peaks from the selected quantitative peak. This method collects a small quantity of target analyte from low-purity organics by LC. After drying and re-dissolving in deuterated solvent containing internal standard, the solution was analyzed by ¹H NMR and HPLC. Another solution prepared by accurately weighing unpurified low-purity substance and internal standard was analyzed by HPLC. Based on the theoretical derivation derived from the Beer-Lambert law, using the ratio of the HPLC peak areas of two solutions as correction, the purity was then calculated without the same reference as target analyte. Compared to previous methods with similar selectivity and accuracy, it has advantages such as a less purified sample is required, time for lyophilization is reduced by half, and sample preparation is more controllable. The proposed method was verified by analysis of a suite of six commercially available, high-purity compounds, and the difference of results between it and direct qNMR was within 0.1%. The result of pyributicarb using ISC-HPLC-qNMR was 97.6% (U = 0.5%; k = 2), and the reference value was 97.61% (U = 0.22%; k = 2). The results demonstrate that the proposed method provides a new way for reference material producers to calibrate lower-purity organics and has the potential advantage of accurate quantification of lower-purity organics.

建立内标校正-高效液相色谱-定量核磁共振（ISC-HPLC-qNMR）程序作为一种可靠的低纯度复杂有机化合物定量方法，以解决因分辨率不足而导致qNMR不准确的风险来自所选定量峰的杂质峰。该方法通过 LC 从低纯度有机物中收集少量目标分析物。干燥并重新溶解在含有内标的氘代溶剂中后，通过¹H NMR 和 HPLC。另一种通过准确称量未纯化的低纯度物质和内标制备的溶液通过 HPLC 进行分析。根据 Beer-Lambert 定律的理论推导，使用两种溶液的 HPLC 峰面积比作为校正，然后在没有与目标分析物相同的参考的情况下计算纯度。与以往的方法相比，具有相似的选择性和准确度，具有样品纯化量少、冻干时间减半、样品制备更可控等优点。通过分析一套六种市售的高纯度化合物对所提出的方法进行了验证，其结果与直接 qNMR 的结果差异在 0.1% 以内。使用 ISC-HPLC-qNMR 的嘧啶威的结果为 97.6% ( U = 0.5%; k  = 2），参考值为97.61%（U  = 0.22%；k  = 2）。结果表明，所提出的方法为标准物质生产商校准低纯度有机物提供了一种新方法，并具有准确定量低纯度有机物的潜在优势。