顶空-气相色谱法测定食用植物油中溶剂残留的方法研究

建立顶空-气相色谱法测定食用植物油中六号溶剂残留量的分析方法.通过优化顶空进样器的平衡温度和平衡时间,使六号溶剂的主要组分完全分离,采用外标法进行定量.在2.0~100.0 mg/kg质量分数范围内,线性关系良好.在低、中、高3个加标水平下,平均回收率是98.2%~99.2%,相对标准偏差是小于2%.方法简便、准确,适合于食用植物油中六号溶剂残留量的测定.     

基于Bayes统计的蔬菜产品质量安全监控系统研究

利用中山市蔬菜产品抽样检测数据,运用Bayes统计方法,建立了蔬菜产品污染指数:并根据休哈特控制图原理,确定μ、μ+2σ、μ+3σ三条监控限,将蔬菜产品质量安全状况水平分成"优秀"、"良好"、"轻度污染"、"污染"四个监控区域,建立蔬菜产品质量安全监控图。为广大市民、政府部门、农产品市场和生产部门提供及时的蔬菜产品污染水平和质量状况信息。     

Development of wood protective polyurethane coatings from mahua oil-based polyetheramide polyol: a renewable approach

The present work reports the preparation of wood protective polyurethane (PU) from mahua oil-based polyetheramide polyol and its performance evaluation. The synthesis of polyetheramide polyol was carried out in two steps: the first step deals with the synthesis of mahua oil fatty amide (MFA) from mahua oil by base catalyzed aminolysis reaction and the second step deals with the synthesis of polyetheramide polyol from diglycidyl ether of bisphenol-A (DGEBA) and MFA. The structure of the synthesized polyetheramide polyol was confirmed by the Attenuated total reflection fourier transform infrared (ATR-FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy. The synthesized polyetheramide polyol was used as a precursor for the wood protective PU coatings. The performance of the prepared wood protective PU coatings was evaluated by the measurements of the various performance properties. The results reveal that mechanical, thermal, and microbial properties of the prepared PUs are satisfactory compared to other literature reported vegetable oil-based PUs; whereas, water, solvent, and chemical resistance of the prepared PUs are quite good. The study concludes that mahua oil-based polyetheramide polyol is a suitable precursor for the preparation of wood protective PU.     

Biobased polyurethane adhesive over petroleum based adhesive: Use of renewable resource

This review article is based on the recent trends and development of biobased polyurethane (PU) adhesives from vegetable oil. A detail discussion has been reported about the PU adhesive starting from petroleum based to biobased source. Special attention has been given towards the utilization of castor oil based PU in adhesive technology, due to the wide range of castor oil among all vegetable oil. The appreciable adhesion, mechanical, thermal properties of vegetable oil based PU adhesives were compared with petroleum based PU adhesive, which were utilized to meet the specific application in adhesion industry.     

Synthesis,characterization, and surface properties of amide amine oxides based on natural vegetable oil

Two types of novel amine oxide surfactants, castor oil amide amine oxide and cottonseed oil amide amine oxide, have been successfully synthesized via a two-step synthetic route with mild reaction conditions, the chemical structures of which were confirmed by mass spectra (MS) and FTIR spectra. Their surface activities have been measured. The results show that these synthesized amide amine oxide surfactants reduced the surface tension of water to a minimum value of approximately 32.48 mN/m at a concentration of 5.06?×?10^?5?mol/L. It was also found that these novel amide amine oxide surfactants exhibited strong emulsifying power.     

Analytical Method Validation and Determination of Iron and Phosphorus in Vegetable Oil by Inductively Coupled Plasma–Mass Spectrometry with Microwave Assisted Digestion

Inductively coupled plasma–mass spectrometric determination of iron and phosphorus in three vegetable oils (soybean, coconut, and sunflower) was validated for the intermediate precision, trueness, linearity, and quantitation limit. The overall precision (n?=?5) for the analytes, which were above the method’s practical limit of quantification, were less than 2% relative standard deviation and the same as the laboratory control, NIST-SRM-1849a. Trueness was demonstrated with spike recoveries of the analytes in all vegetable oils at limit of quantification-level spiking. Although good linearity (regression coefficient greater than 0.9990) obtained, the recovery of phosphorus (156–189%) was high, possibly due to oil matrix enhancement, compared to the recovery of iron (91–106%). For soybean oil, sunflower oil, coconut oil, and medium chain triglycerides, the concentrations (mg/kg) of iron were in the range of 0.10–1.47, 0.09–1.51, 0.20–0.35, and 0.09–0.13, respectively. Similarly, phosphorus concentrations (mg/kg) were in the range of 0.77–124.56, 0.49–125.57, 0.52–9.72, and 0.85–11.90, respectively. The study achieved considerably low instrument-based practical limits of quantification for iron (0.005?mg/kg) and phosphorus (0.05?mg/kg), which are fivefold lower than the AOAC Official Method 2015.06. The high instrument sensitivity and selectivity of the method allow the determination of trace levels of iron and phosphorus in vegetable oils with good precision and trueness.     

松香改性酚醛树脂的合成反应

研究了胶印油墨连接料用松香酚醛的合成反应，得出采用滴加酚醛浆的二步法合成工艺，可以有效地控制羟甲基酚经分子内脱水形成的次甲基酯。生成的苯并二氢吡喃型产物能显著地提高改性树脂的分子量和油溶性。     

冷原子荧光法测定蔬菜中痕量汞的不确定度评定

对冷原子荧光法测定蔬菜中痕量汞的不确定度进行了评定。不确定度来源主要为配制标准工作溶液引入的不确定度,称取样品质量引入的不确定度,样品消化引入的不确定度,定容体积引入的不确定度,重复测定引入的不确定度。当蔬菜中汞含量为5.2μg/kg时,测量结果的扩展不确定度为0.50μg/kg。     

气相色谱–质谱法测定食用植物油中短链脂肪酸的测量不确定度评定

采用气相色谱–质谱法(GC–MS)测定食用植物油中短链脂肪酸含量,对测量结果的不确定度进行评定,探讨提高测量准确度的方法。依据方法建立数学模型,分析得出不确定度主要来源于样品制备过程、计量器具的使用、标准溶液配制、测量设备、人员读数误差、方法回收率,计算各不确定度分量,得到相对标准不确定度和扩展不确定度。结果表明,当食用植物油中短链脂肪酸测定结果为13.1 mg/kg时,其扩展不确定度为1.8 mg/kg(k=2)。测量设备、标准溶液配制过程引入的不确定度较大,应在实验过程中予以控制和关注。     

液相色谱–串联质谱法测定蔬菜中6种极性农药残留量

建立了百草枯、敌草快、矮壮素、缩节胺、单甲脒、灭蝇胺6种极性农药的液相色谱–串联质谱测定方法。采用SCX和C_(18)复合填料(质量比为1∶20)的Shiseido CAPCELL PAK CR色谱柱分离,用超高压液相色谱–串联质谱仪测定。利用响应面法优化得到样品的前处理条件,蔬菜样品用甲酸–乙腈溶液均质提取,三氯甲烷液–液萃取净化,在定量限的1,2,10倍浓度水平,回收率在61.7%~116.8%之间,测定结果的相对标准偏差不大于13.6%(n=6)。该法适用于蔬菜中百草枯、敌草快、矮壮素、缩节胺、单甲脒、灭蝇胺残留量的测定。