氨鲁米特

[em01] [img]http://ng1.17img.cn/bbsfiles/images/2005/06/200506241402_5945_1296401_3.jpg[/img]LumiMax-C : Attomoles LuminometerDetecting Proteins and Nucleic Acids with Ultra-SensitivityBy Maxwell Sensors Inc. (562) 801-2088 USA, http://www.maxwellsensors.com LumiMax-C is a compact model designed for ultra-sensitive chemiluminescence and bioluminescence detection. The system measures luminescence intensity in a 96-well microplate (black, white, or opaque). These microplates have microwells with clear bottoms, allowing the luminescence to be detected from the bottom of the well. Many companies, such as Nunc, Costar, Corning, BD Biosciences, Perkin Elmer, etc., have microplates for luminescence applications. Because LumiMax-C uses a state-of-the-art photoncounting multiplier tube as the detector, the system is extremely light sensitive. LumiMax-C has the ability to accurately count the number of photons generated from a chemiluminescent or bioluminescent experiment, allowing the system to detect very small amounts of analyte, in the range of attomoles, in the samples. The detector is sensitive in all visible ranges. LumiMax-C combines the latest, low-noise detector and electronic circuitry to provide very low background noise and very high signal levels. Its broad dynamic range covers over 6 orders of magnitude. The superior mechanical design eliminates most of the cross-talk down to ~ 10-5 between the adjacent wells. The system is flexible and easy to use. The user can select to scan any one or any set of the 96 wells, at a measuring time of 0.1-10 seconds per well. The system can also be used for kinetic and luminescence time profile studies. After clicking on the “Go” button, the system will automatically and quickly scan all of the reactions in the microwells and display the results.LumiMax-C utilizes a Windows-based PC or notebook as its microprocessor. The system is interfaced to a computer by a simple plug-in (serial port or USB) connection. A CD, with user-friendly software, is provided for easy installation. The resulting data is displayed as a spreadsheet in Microsoft-Excel or other format. The data, reported as number of optical counts, is displayed as it is collected. The system also offers software with easy click on data processing for routine calibration or operation. The system dimensions are approximately 16” x 11 “ x 4” and at 20 lb, it is easily portable for sharing between laboratories or researchers.

使用聚醚多元醇合成的聚氨酯一般被称作聚醚型聚氨酯，在聚醚型聚氨酯的分析过程中，最常用的仪器有NMR、Py-GCMS、MS、MALDI-TOF等，单体的种类一般通过Py-GCMS与MS进行定性，通过NMR进行定量。 聚醚多元醇的性能与起始剂密切相关，也与分子中氧化烯烃链段长度及排列结构有关。聚醚多元醇的官能度取决于合成时所选择起始剂的活泼氢数目。不同聚醚型聚氨酯产品中使用的聚醚多元醇的结构有所不同，在设计产品的时候往往选用多种聚醚复配使用。对复杂混合聚醚进行结构解析难度不小，而对于聚氨酯预聚体与树脂中的聚醚多元醇的解析则难度更大。 我们选取了几十款市面上常用的聚醚多元醇，对各种聚醚多元醇进行了原样的表征；然后将其与不同的异氰酸酯反应合成了不同的预聚体，对不同的预聚体进行了表征；最后针对预聚体进行了扩链合成了树脂，再针对树脂进行了表征，提高了微谱分析整体对该类产品定性定量的准确度。一、HNMR 不同单体（环氧丙烷、环氧乙烷、四氢呋喃）合成的聚醚多元醇在NMR上的主体出峰明显不同，如下图，为三种常用的聚醚多元醇（204、210、220）的NMR出峰，其中三种聚醚的起始剂均为1,2-丙二醇，单体均为环氧丙烷，分子量分别为400、1000、2000。可以看出在NMR图谱上面3.7ppm附近的出峰面积比例有明显的变化，该位置体现了聚醚多元醇的端位的出峰，根据该位置的出峰可以区别聚醚的结构。[align=center][img=,690,352]http://ng1.17img.cn/bbsfiles/images/2018/07/201807120944210335_7386_2879355_3.jpg!w690x352.jpg[/img][/align] 当我们将以上聚醚多元醇与MDI进行预聚反应生成端-NCO聚氨酯时，聚醚多元醇的端位羟基与NCO发生了反应，端位化学位移到了5.0ppm左右。而当我们将MDI换成HDI，情况则又有变化，该数据可以用于预聚体的结构解析。我们也用小分子二元醇对预聚体进行扩链，对扩链之后的树脂的NMR图谱也进行了深入的研究。一、MALDI-TOF 由于含量低，且单体出峰容易遮挡，聚醚的起始剂解析难度大，MALDI-TOF是解析的主要手段。 在MALDI-TOF图谱上，聚醚的特征出峰一般是间隔58（环氧丙烷）、44（环氧乙烷）的多组特征峰，通过计算解析可以得到聚醚的起始剂的分子量。图2.1、2.2分别为聚醚210与聚醚220的MALDI-TOF图谱，解析可知起始剂的分子量均为76（或134），判断可能为丙二醇或三羟甲基丙烷等，结合羟值等参数可知为丙二醇，图2.3为聚醚210与聚醚220与MDI反应生成预聚体的MALDI-TOF图谱，可明显找到MDI-210-MDI与MDI-220-MDI的出峰，进一步通过NMR等图谱可以解析出两种聚醚的比例。我们对市面上大部分常用聚醚均进行了如上表征，可以将聚醚起始剂、单体种类比例、分子量、封端等信息解析清楚。[align=center][img=,690,223]http://ng1.17img.cn/bbsfiles/images/2018/07/201807120944522185_2255_2879355_3.jpg!w690x223.jpg[/img][/align][align=center]图2.1[/align][align=center][img=,690,304]http://ng1.17img.cn/bbsfiles/images/2018/07/201807120945309075_7358_2879355_3.jpg!w690x304.jpg[/img][/align][align=center]图2.2[/align][align=center][img=,690,242]http://ng1.17img.cn/bbsfiles/images/2018/07/201807120946094565_5977_2879355_3.jpg!w690x242.jpg[/img][/align][align=center]图2.3[/align] 针对于更复杂的情况，如多种聚醚预聚体，或聚醚型聚氨酯树脂等，我们一般采取水解的方法，在经过多种后续处理后将聚氨酯中的聚醚还原，然后进行多种测试、解析。 除此之外，我们还对以上结构的物质进行了CNMR、Py-GCMS等多种测试并研究，这对我们在聚醚型聚氨酯产品分析中起到了很大的帮助。[list][*]声明：本文资料为“上海微谱化工技术服务有限公司”原创，未经允许不得私自转载。否则我司将保留追究其法律责任的权利。[/list]