油品中全谱检测方案(光谱配件)

Stability in pathlength repeatabilityallows the PearlTM to be used in theaccurate study of liquids. AN5 Figure 2： (a) Absorption band at 1460cm-1 for all 28spectra (b) Spread of intensities relative to the baseline This note demonstrates the repeatability of a 25 pmpathlength cell， called an Oyster Cell， comprising ZnSewindows. More information on the Oyster Cell can befound at www.specac.com Figure 3. Variation in baseline of spectra shown in Fig.1 Results & discussion Figure 1 shows 28 absorption spectra of 5 pl of RenolinCL37 oil recorded using a 25 pm pathlength ZnSewedged window cell. The spectra are shown again in Figure 2(a)， focusing onthe absorption band at 1460 cm-. The relative absorbance intensity was used rather thanthe absolute absorbance to remove the variation in thebaseline， shown in Figure 3， which was determined to beon the order of 0.01. Therefore， the variation in the relative absorbanceintensity is used to determine the standard deviation，Figure 2(b). This allows us to determine thereproducibility of the 25 pm cell pathlength. The variation in the spectrometer itself was measured byrecording 10 spectra of an empty cell. It was determined to be on the order of 0.001 and hencerelatively negligible. The relationship between theabsorbance of a cell and the pathlength is linear. Based on Figure 2， there is standard deviation of 0.77 ofthe average absorbance. This correlates to a 0.2 pmerror in the pathlength of the cell. Conclusions The stability in pathlength repeatability， demonstrated inthis note， enables the Pearl to be used in quantitativestudies of liquid samples with a high degree of accuracy. Based on the internal manufacturing process andcontrols used in the construction of the Pearl and theOyster Liquid Cell，we can assume that a standarddeviation of 0.2 um would be constant across the widerange of pathlengths available. Further examples of pathlength reproducibilityy aaireplanned to further validate this capability. And similar studies are being performed for even moreviscous samples such as greases and honey. The variation in the pathlength should be the same forboth ZnSe and CaF2 windows. Email sales@specac.com or visit www.specac.com formore information or aafree demonstration. Otherapplication notes are available on the Specac website. pearl 珍珠池解决了针对粘性，油类等这样的样品，测试清洁快速，没有残留影响，以及多次测试重复性更好，采用楔形窗片后，针对小量样品消除干涉条纹，使得测试谱图更加清晰。具体请参看文件。