巧克力中化学成分检测方案(光谱配件)

Analysing chocolate using thePearlM accessory COCOA BEANS are a versatile foodstuff that producetasty treats and sweet scents. Confectionaries likechocolate bars can be made with different fat， sugar andwater ratios. Food industries want a fast， reliable and non-destructivemethod to analyse chocolate chemical composition. This note demonstrates that the PearlTM IR transmissionaccessory can be used to determine the quality andcontent of chocolate in post-production， for qualityassessment purposes. Methods and results A small sample of a well known milk chocolate (~10 mg)was warmed gently and pasted onto the bottom ZnSewindow of the PearlTM Oyster Cell. The pathlength of thecell was 25 pm but longer pathlengths are available forweaker absorbing samples. Figure 1 shows the FTIR spectrum of the chocolate， asrecorded using the PearlTM in a spectrometer and with aresolution of 2 cm-1over an average of 10 scans. The fingerprint region in Figure 1 displays the hallmarks of cocoaproducts， mostnotably the C=Ostretch at 1758cm-1， typical of anester and the CH2at absorption from fat The PearlTM Iliquid IR transmissionaccessory is perfect for chocolatequality-check analysis. AN4 1462 cm-1. Other significant peaks include theabsorption bands at 2924 & 2854 cm-1. Figure 1： chocolate recorded using the PearlIM The intensities of these bands can be used to assess thequality of the chocolate. A published FTIR spectrum of cocoa butter is shown inFigure 2， recorded using the Specac Golden GateTM ATRaccessory. This spectrum was taken from a study featured inAnalytica Chimera Acta， which is available on the WorldCocoa Foundation's website. Figure 2 is complementary to the spectrum recordedusing the PearlTM. Moreover， the ability to distinguish thefat content for different cocoa butter samples isdemonstrated. Figure 2： reference spectrum1 of cocoa butter recorded with Golden GateTM Conclusions Recording FTIR spectra using the PearlTM is a quickmethod to determine the chemical composition of cocoaproducts. Moreover， the PearlTM offers a user-friendlyway of recording reproducible and reliable spectra. The PearlTM IR transmission accessory comes in different colours The recorded spectrum matches quite well with theliterature and therefore the PearlTM would be suitable forthe cocoa industry. References 1 A.Vesela， A.S. Barros， A.Synytsya， l.Delgadillo， J.Copikova，M.A.Coimbra，“Infrared spectroscopy and outer productanalysis for quantification of fat， nitrogen， and moisture ofcocoa powder，" Analytica Chimica Acta， 601，(1)，77-86，2007. 特点：比传统的液体池配件测定更加快速，便捷，重复性更好楔形窗片选项可有效消除衍射波纹更换不同材质的窗片或者更换不同光程的液体池，仅需几秒钟非常适合粘稠液体的测定，清晰快速，不漏液，随意添加Pearl 液体测定附件Pearl附件包括SPCAC最新型的Oyster®合页打开式液体池附件，可将样品水平放置，顶部Oyster液体池可轻易打开翻过来，以便快速放入样品，并易清洁，针对易挥发等液体，在Osyter顶部设计了一个注射口，因此样品池不用完全打开。客户可以清晰的从窗片观察样品，并轻微的调整窗片以去除样品中的气泡。Osyter 样品池清洗非常的方便和快捷，只需清洁布快速的擦拭即可。Pearl珍珠系列附件与传统的液体池相比，同时也提供多款不同光程的附件，测定的重复性小于1um， Oyster也可以选择楔形窗片earl 的快速测定法非常适合测定粘稠以及粘度较高的样品，如油类，油中水，以及脂类，食品溶液，牛奶等酸碱液体。 Benchmark™底座系统 轻易安装。