Zhou Zhe, Kümmerle Rainer, Qiu Xiaohua, Redwine David, Cong Rongjuan, Taha Angela, Baugh Dan, Winniford Bill
The Dow Chemical Company, 2301 N. Brazosport Blvd., Freeport, TX 77541, USA.
J Magn Reson. 2007 Aug;187(2):225-33. doi: 10.1016/j.jmr.2007.05.005. Epub 2007 May 23.
(13)C NMR is a powerful analytical tool for characterizing polyethylene copolymer composition and sequence distribution. Accurate characterization of the composition and sequence distribution is critical for researchers in industry and academia. Some common composite pulse decoupling (CPD) sequences used in polyethylene copolymer (13)C NMR can lead to artifacts such as modulations of the decoupled (13)C NMR signals (decoupling sidebands) resulting in systematic errors in quantitative analysis. A new CPD method was developed, which suppresses decoupling sidebands below the limit of detection (less than 1:40,000 compared to the intensity of the decoupled signal). This new CPD sequence consists of an improved Waltz-16 CPD, implemented as a bilevel method. Compared with other conventional CPD programs this new decoupling method produced the cleanest (13)C NMR spectra for polyethylene copolymer composition and triad sequence distribution analyses.
碳-13核磁共振（(13)C NMR）是表征聚乙烯共聚物组成和序列分布的强大分析工具。准确表征组成和序列分布对于工业界和学术界的研究人员而言至关重要。聚乙烯共聚物碳-13核磁共振中使用的一些常见复合脉冲去耦（CPD）序列会导致伪影，例如去耦碳-13核磁共振信号的调制（去耦边带），从而在定量分析中产生系统误差。开发了一种新的CPD方法，该方法将去耦边带抑制到检测限以下（与去耦信号强度相比小于1:40,000）。这种新的CPD序列由改进的Waltz-16 CPD组成，采用双电平方法实现。与其他传统CPD程序相比，这种新的去耦方法为聚乙烯共聚物组成和三元组序列分布分析产生了最清晰的碳-13核磁共振谱。
