食品接触用塑料产品中19种邻苯二甲酸酯类增塑剂GC-MS检测研究

研究建立了食品接触用塑料产品中19种邻苯二甲酸酯类增塑剂的气相色谱-质谱联用仪(GC-MS)法快速检测方法。塑料产品以正己烷为萃取溶剂,采用超声萃取法对产品中邻苯二甲酸酯类增塑剂进行萃取,萃取液浓缩过滤后进行测定。19种邻苯二甲酸酯类增塑剂在0.05~1mg/L、0.5~10mg/L范围内线性良好,方法检出限(MDL)为0.1238mg/kg~0.9714mg/kg,加标回收率为89.6%~112.9%,相对标准偏差(RSDs)为2.61%~6.36%。该方法重现性好,检出限低,检测结果准确,可用于食品接触用塑料产品中19种邻苯二甲酸酯类增塑剂含量的检测,为食品接触材料中邻苯二甲酸酯质量控制提供相应的技术支撑。     

气相色谱-串联质谱法测定玩具产品中23种增塑剂

采用超声萃取样品,建立了气相色谱-串联质谱法(GC/MS/MS)测定玩具产品萃取液中23种邻苯二甲酸酯类增塑剂含量的方法。样品以二氯甲烷为萃取溶剂,超声波辅助萃取后,采用多反应监测(MRM)模式进行测定。结果表明,在0.01~1.0 mg·L~(-1)浓度范围内,23种邻苯二甲酸酯类增塑剂线性关系良好(r0.998),回收率均在80.5%~105.9%之间,RSD在2.48%~9.26%之间,该方法检测限在0.4~5.0μg·kg~(-1)之间。该方法选择性强、灵敏度高、重复性好,能满足玩具产品中多种材料的增塑剂含量的测定。     

气相色谱-质谱/离子选择法对PE保鲜膜中邻苯二甲酸酯类的测定

增塑剂中的邻苯二甲酸酯类严重影响人类的生命健康。该文以正己烷为萃取剂,采用超声萃取法提取PE保鲜膜中的邻苯二甲酸酯;利用气相色谱-质谱法/选择离子监测模式(GC-MS/SIM),测定PE保鲜膜中的4种邻苯二甲酸酯(DBP、BBP、DEHP、DNOP)的含量;建立气相色谱-质谱/离子选择法测定PE保鲜膜中邻苯二甲酸酯含量的分析方法。实验结果表明该方法在0.1~0.8 mg/L范围内具有良好的线性关系,检测限在0.20~0.60 mg/kg之间,加标水平为0.3 mg/L时的平均回收率为80.2%~104.8%,测定结果的相对标准偏差为1.76%~5.52%。该方法操作简便、准确性好、快速、灵敏,适于PE保鲜膜中4种邻苯二甲酸酯类含量的测定。     

GC-MS法同时测定橡皮擦中22种邻苯二甲酸酯增塑剂

建立了气相色谱-质谱(GC-MS)分段选择离子监测(SIM)模式分析同时测定橡皮擦中22种邻苯二甲酸酯(PAEs)增塑剂含量的方法。该方法具有良好线性,相关系数R均大于0.999,检测限在1.3 mg/kg～128.9 mg/kg之间,平均回收率在70.2%～105.6%,相对标准偏差在2.57%～9.88%之间。通过该方法对国内橡皮擦中PAEs增塑剂进行检测,实际样品均检出邻苯二甲酸二(2-乙基)己酯(DEHP),含量最高达32.5%。     

ATR-FTIR法测定PVC食品包装材料中邻苯二甲酸酯

目的为建立有效的邻苯二甲酸酯类增塑剂使用规范和监管制度,建立衰减全反射(ATR)-红外光谱法(FTIR)测定聚氯乙烯(PVC)食品包装材料中邻苯二甲酸酯类增塑剂含量的检测方法。方法以聚氯乙烯食品包装材料为研究对象,利用ATR-FTIR法直接测定。结果邻苯二甲酸酯质量分数为0.5%~35%的PVC,具有1610~1570 cm~(-1)和750~720 cm~(-1)共计2处红外特征峰,且相关系数达到0.9994,线性关系良好;该法测定的精密度相对标准偏差均小于5.0%,准确度相对偏差绝对值均在10%以内。结论该方法简便、快速、环保,能够满足聚氯乙烯食品包装材料中快速检测邻苯二甲酸酯类增塑剂的要求。     

文具产品中6种邻苯二甲酸酯的测试

提出气相色谱-质谱联用仪同时测定文具中6种邻苯二甲酸酯类增塑剂的方法,以正己烷为溶剂,采用索氏提取法提取文具中6种邻苯二甲酸酯类增塑剂,采用外标法进行定量。该方法平均回收率为87.6%¹03.1%,相对标准偏差为0.45%103.1%,相对标准偏差为0.45%⁴.17%,检出限分别为0.5mg/kg(邻苯二甲酸二丁酯DBP),0.75mg/kg(邻苯二甲酸丁苄酯BBP),0.75 mg/kg[邻苯二甲酸二(2-乙基)己酯DEHP],1.0 mg/kg(邻苯二甲酸二正辛酯DNOP),5.0 mg/kg(邻苯二甲酸二异壬酯DINP),5.0mg/kg(邻苯二甲酸二异癸酯DIDP)。     

分散固相萃取法测定食品中酞酸酯类物质

建立分散固相萃取-反相液相色谱法同时测定食品及模拟物中6 种痕量邻苯二甲酸酯类增塑剂(PAEs)的方法。采用正交试验分析了以HLB 为吸附材料富集净化的萃取条件,确定解析溶剂乙腈的用量为6 mL,硫酸镁为120 mg,氯化钠为120 mg。该法检测6 种样液中6 种物质峰面积对浓度进行线性回归的相关系数大于0. 999,相对标准偏差为0.3% ~4. 7% (n =5),平均回收率为62. 9% ~105. 0%,检测限为0. 019 ~0. 046 mg/ kg。该法简易、高效、成本低,具有较高回收率。     

微波辅助萃取-气质联用/选择离子监测法同时测定涂布纸中多种邻苯二甲酸酯类增塑剂

以丙酮为萃取溶剂,采用微波辅助萃取技术萃取涂布纸中的邻苯二甲酸酯类增塑剂,萃取产物进行气相色谱/质谱-选择离子监测法测定,从而建立了一种同时测定涂布纸中多种邻苯二甲酸酯类增塑剂的方法。该方法简便快捷、灵敏度高、定性定量准确。方法的精密度试验RSD为3.12-5.97%,加标平均回收率为82.35-103.68%。在S/N=3的条件下,DINP和DIDP的检出限分别为1.0、2.0mg/kg,其余各组分检出限均小于0.4mg/kg。本方法可用于涂布纸中多种邻苯二甲酸酯类增塑剂的同时测定。     

纸包装中邻苯二甲酸酯类塑化剂检测方法

建立食品用纸包装中邻苯二甲酸酯塑化剂分析测定方法。本实验使用正己烷超声波震荡30min与涡旋振荡3min结合的方法提取食品用纸包装中邻苯二甲酸酯类增塑剂,采用气相-质谱(GC-MS)进行定性及定量分析,样品经DB-5MS毛细管色谱柱分离,以选择离子监测模式(SIM)检测。DEHP、DBP和DIBP在0.04-2.00μg/m L浓度范围内,峰面积与进样浓度的线性关系良好,相关系数均大于0.995,3种塑化剂加样回收率80.61%-93.51%,样品的精密度试验的RSD均小于2%,最低检出限1.0mg/kg。该分析方法简便、快捷、定性定量可靠。24种食品纸包装中的DEHP、DBP和DIBP的含量有所差异,印刷样品中增塑剂的含量较未印刷样品中的含量要高,淋膜样品中增塑剂的含量较未淋膜样品中的含量要高,应给予高度重视。     

汽车用胶黏剂产品中16种邻苯二甲酸酯类增塑剂的快速检测

目的:本研究采用气相色谱-三重四极杆质谱联用技术,同时结合改进的QuEChERS技术,建立了汽车用胶黏剂产品中16种邻苯二甲酸酯类增塑剂(PAEs)的同时检测技术。方法:样品经乙腈溶液提取,无水硫酸钠和氯化钠盐析后,经N-丙基乙二胺(PSA)填料净化,多反应监测模式,外标法定量。结果:16种增塑剂在0.05-20μg/mL范围内存在良好的线性关系,相关系数r在0.9902-0.9981之间;在0.02、0.2、2.0 mg/kg的加标水平下,回收率为80.7%-106.2%,相对标准偏差为0.41%-11.4%;检出限(S/N=3)与定量限(S/N=10)分别为0.05-0.33mg/kg和0.18-1.09 mg/kg。结论:该方法准确性和重复性好、灵敏度高,完全满足汽车用胶黏剂产品的检测需要。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.