热裂解气相色谱/质谱联用鉴定药用胶塞胶种

采用高温热裂解结合低温解吸附处理药用胶塞,用气相色谱/质谱联用进行胶种定性分析。结果表明,普通IIR、溴化丁基橡胶(BIIR)、氯化丁基橡胶(CIIR)、IR、BR和EPDM的热裂解产物的总离子流或选择离子流色谱中均有特征色谱峰,可进行定性鉴定。该鉴定方法无需预处理样品,结果准确、可靠。     

裂解气相色谱/质谱联用研究防焦剂CTP的热裂解

采用裂解气相色谱/质谱联用法对防焦剂CTP的热裂解行为进行研究,并对部分热裂解产物的质谱碎裂机理进行探讨。结果表明:防焦剂CTP热裂解适宜条件为温度300℃,时间0.2 min,方式单纯瞬间裂解,固体样品直接进样;不同产地产品的裂解产物具有一致性,热稳定性好;裂解产物共10余个,主峰为原分子,次强峰为邻苯二甲酰亚胺。解析了NIST谱库中不包含的主要裂解产物可能的质谱裂解途径;可根据其中环己硫醇、邻苯二甲酰亚胺、二环己基二硫化物3个裂解产物共同判断防焦剂CTP的存在。     

热裂解/气相色谱-质谱法测定聚氯乙烯农膜中的DEHP

建立了热裂解/气相色谱-质谱联用技术测定聚氯乙烯农膜中邻苯二甲酸二(2-乙基)己酯(DEHP)的定性定量分析方法。通过热裂解方式,使样品快速裂解汽化,设定并优化参数,用碎片离子149进行定量,NIST谱库检索。结果表明:热裂解/气相色谱-质谱法测定样品加标回收率为93.2%,相对标准偏差为1.6%,相关系数在0.995以上,最低检出限为0.1 mg/kg,定量限为0.3 mg/kg。该方法操作简捷、快速、灵敏度高、重复性好,适合测定聚氯乙烯农膜中的DEHP。     

CR的热裂解色谱/质谱分析

采用气相色谱／质谱对ＣＲ热裂解产物进行分析,获得了表征ＣＲ的单体和二聚体及其有关结构的信息。研究了裂解温度对单体和二聚体相对质量分数的影响,并从理论方面讨论了ＣＲ热裂解的机理和二聚体的主要结构。     

高抗冲击聚苯乙烯的热裂解气相色谱／质谱分析

利用热裂解气相色谱/质谱法对高抗冲击聚苯乙烯(HIPS)树脂样品进行了分析。通过总离子图分析，给出了其热裂解产物，并结合化学萃取分离方法确定了HIPS的组成为聚苯乙烯和聚丁二烯的共混物，其质量分数分别为0．943和0．057。     

热裂解-冷阱聚焦-气相色谱/质谱联用法研究烟草中芸香苷的热裂解行为

采用热裂解-冷阱聚焦-气相色谱/质谱法(Py-CIS-GC/MS)研究了烟草中芸香苷的热裂解行为。在氮氧混合气体积比为9∶91氛围中,以程序升温的方式模拟卷烟真实燃烧状态的热裂解试验过程并通过GC/MS对其热裂解产物进行定性和半定量分析。结果表明,芸香苷可裂解出糠醛、山梨酸、2-吡喃酮、2-乙酰-丁内酯等62种裂解产物。随着裂解温度的升高,裂解产物越来越复杂,并出现苯酚、儿茶酚、对苯二酚等有害物质。根据密度泛函理论(DFT)方法,结合主要裂解产物及其相对含量,推导出芸香苷可能发生的裂解机理。     

气相色谱/质谱联用法测定炭黑中的多环芳烃含量

利用气相色谱/质谱联用法测定炭黑中8种多环芳烃(PAHs)含量。确定最佳试验条件如下:萃取剂甲苯,水浴超声萃取温度60℃,样品质量/萃取剂体积比0.25 g/10 m L,萃取时间90 min。内标法测定标准曲线的线性相关因数不小于0.998,相对标准偏差小于8.7%。该方法操作简单、灵敏、准确,可用于炭黑中PAHs含量的测定。     

裂解气相色谱/质谱联用分析防老剂DTPD

采用裂解气相色谱/质谱（PGC/MS）联用法,对不同工艺的防老剂DTPD进行分析检测。结果表明,在裂解温度为300℃和700℃下,该方法可以检测不同工艺生产的防老剂DTPD中有效成分含量。     

裂解气相色谱/质谱联用仪分析RT培司的杂质

采用裂解气相色谱/质谱联用(Py-GC/MS)仪分析RT培司(对氨基二苯胺)所含的杂质。结果表明:将RT培司和疑似杂质的导热油样品直接进样,通过GC谱峰的保留时间和MS谱的特征离子推断RT培司样品中的杂质为导热油。RT培司生产过程应避免此类物质的污染,以提高产品纯度。     

气相色谱-质谱联用测定白酒中的甜蜜素

本文采用气相色谱-质谱联用方法测定白酒中甜蜜素的含量。研究了前处理条件的影响,如硫酸浓度、次氯酸钠浓度、反应温度、正己烷体积等,通过单因素实验和正交实验设计确定了最佳条件。此法能有效消除测定结果出现假阳性的可能,且快速高效,可用于白酒中甜蜜素的测定,具有实际应用价值。     

乙烯-乙酸乙烯酯共聚物中乙酸乙烯酯的红外光谱法测定

利用ATR技术测量样品的红外光谱,采用偏最小二乘法对所测光谱进行分析,建立了一种快速分析方法;对乙烯-乙酸乙烯酯共聚物中乙酸乙烯酯进行测定。结果表明：标准曲线线性关系良好,相关系数为0．99985,方法简单快速,结果可靠。     

Acid properties of mazzite zeolites studied by IR spectroscopy

The adsorption of ammonia, pyridine and benzene on non-dealuminated (Si/Al = 4.4) and dealuminated (Si/Al = 10 and 30) mazzite samples was followed by FT-IR spectroscopy. The dealumination of mazzites (by steaming and acid treatment) made all their narrow channels accessible to pyridine. Pyridine and ammonia adsorption and desorption showed that the broad OH band at approximately 3600 cm⁻¹ was composed of several submaxima corresponding to hydroxyl groups of various localizations and various acid strengths. With all the mazzite samples, the concentrations of Brönsted acid sites determined by ammonia adsorption were comparable with the values calculated from the chemical composition of zeolites (amounts of Al minus amount of Na) whereas those determined from pyridine adsorption were lower than these values. The greatest difference was found for the non-dealuminated MAZ-4.4, in which pyridine could not reach the sites of the narrow channels. The values of the extinction coefficients corresponding to the OH groups located in the large channels were higher than those corresponding to the OH groups of the narrow channels, thus showing the stronger acidity of the former OH groups. The acid strength of OH groups increased with the dealumination, as seen from the increase in the corresponding extinction coefficient and frequency shift Δν due to the hydrogen bonding of hydroxyl groups with benzene. Furthermore, the protonic acidity of the dealuminated mazzite of Si/Al = 30 was found to be stronger than that of mordenite and beta zeolite with comparable Si/Al.     

Kinetic study of phenolic resin cure by IR spectroscopy

The cure reaction of a commercial phenolic resin (FRD‐5002, Borden Chimie S.A.) has been studied by IR spectroscopy (Fourier transform IR). A phenomenological approach was used to characterize the kinetic of reaction. Various kinetic models, including homogeneous reactions, diffusion‐controlled reactions, phase boundary movement, and nucleation and growth‐type kinetic, have been tested. Kinetic analyses using integral procedures on isothermal data indicate that the cure reaction data can be described above 140°C using the homogeneous first‐order reaction model. The activation energy has been found to be about 49.6 kJ mol⁻¹. At lower temperature, a diffusive mechanism was active, and the kinetic of reaction was well described by the Jander kinetic model. Because of the simple kinetic control active above 140°C, a mechanistic model for the resol cure at these temperatures has been also proposed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2703–2715, 1999     

红外光谱法测定烷基硫酸盐中游离的脂肪醇

建立了用红外光谱法测定十二烷基硫酸钠中游离十二醇的方法,选用标准曲线法,选择 3660cm~(-1)吸收峰为分析谱带,并以四氯化碳为溶剂,在红外液体吸收池内记录其在3680～3050cm~(-1)的A值。方法准确、快速、简便,标准偏差为0.008％,变异系数0.51％,回收率99.8％。     

The interaction of butenes with Cu ions in CuMCM-41 studied by IR spectroscopy

As CuMCM-41 was found to be active in skeletal isomerisation of n-butenes, we followed by IR spectroscopy the interaction of but-1-ene, cis-but-2-ene, and trans-but-2-ene with Cu⁺ sites in CuMCM-41. It has been revealed that Cu⁺ activated strongly CC bond, what resulted in a frequency shift of CC stretching band by about 100 cm⁻¹. Moreover, the vibration of CH bonds in CH₂ and CH groups neighbouring to the double bonds was also perturbed. We suppose that the activation of CC bond is a result of π-back donation of d electrons of Cu⁺ to π^* antibonding orbitals of butenes. IR results evidenced also the heterogeneity of Cu⁺ sites in CuMCM-41 and the presence of Cu⁺ sites of various electron donor properties. But-1-ene molecules bonded to Cu⁺ ions are less prone to accept protons from Brønsted acid sites than molecules bonded by hydrogen bonding to non-acidic SiOH groups, even though they are more negative than free or physisorbed molecules. The IR studies of coadsorption of CO and but-1-ene suggest that the interaction of CO with Cu⁺ is much weaker if but-1-ene is present, than without butene.     

Classification of feeding fats by FT‐IR spectroscopy

In this paper, a technique useful for the classification of different food oil co‐ and by‐products of potential use for feed preparation is shown. The proposal is based upon a Fourier transform infrared evaluation of different classes of compounds, and its elaboration was carried out starting from the knowledge of the chemical composition of each feedstock category. Using this technique, a sure classification of fatty acid calcium soaps, fully hydrogenated fatty acids, lecithins, acid oils from chemical refining, acid oils from physical refining and fish oils can be easily done. The remaining categories of animal fats, fried oils and oils recovered from exhausted bleaching earth can be differentiated by using one or two additional chemical tests. The scope of this paper is to provide a quick, easy and non‐expensive tool for a correct classification of feedstock, in order to allow the choice of correct and applicable analytical tests for the evaluation of the quality and of the composition of each sample.     

Quick identification of polyterephthalate in laundry detergents by simultaneous pyrolysis methylation-gas chromatography/mass spectrometry

This report summarizes method development for the identification of polyterephthalates using simultaneous pyrolysis methylation-gas chromatography with mass spectrometry. Ground detergent products are directly pyrolyzed together with the methylation reagent tetramethylammonium hydroxide. Key fragments separated via gas chromatography are detected by a mass selective detector. Trace levels of polyterephthalates in laundry detergent products were identified within 20 min without interference from surfactants or other organics. Detection limit was 0.05% by weight in product.     

Crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) studied by 2D IR correlation spectroscopy

Crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)) (HHx=12 mol%) was studied by means of two-dimensional infrared (2D IR) correlation spectroscopy. Three types of crystallization; the gradual cooling from the melt, the isothermal crystallization of the supercooled melt, and the isothermal crystallization of the solution-cast film were investigated. The order of crystal growth steps taking place during the three different types of crystallization processes was analyzed in detail. It was revealed by the asynchronous 2D correlation spectra generated from the dynamic IR spectra in the CO stretching band region that the development of the highly ordered crystals occurs prior to that of the less ordered crystals for the gradual cooling crystallization. On the other hand, for the supercooled melt and solution-cast film crystallization, the formation of the less ordered crystals takes place before that of the highly ordered crystals. The transition from the amorphous phase to the less ordered crystals is a simultaneous process for all three types of crystallization.     

Determination of end groups in poly(methylmethacrylate peroxide) by fast atom bombardment mass spectrometry and IR spectroscopy

Summary A detailed comprehensive investigation has been made to unequivocally analyse the end groups of a vinyl polyperoxide polymer namely, poly(methylmethacrylate peroxide), PMMAP, using Fast Atom Bombardment Mass Spectrometric (FABMS) technique. Further evidence to FABMS analysis has been sought from IR spectroscopic analysis on the same polymer. It has been found that PMMAP contains both hydroxyl and hydroperoxide end groups which has been explained by the chain transfer reaction of growing chain with the degradation product of PMMAP.