Volatile organic compounds(VOCs) in soil were extracted by thermal desorption-cold trap,and the extraction conditions were researched with 17 VOCs as objective.The extraction conditions determined through the experiments were as the following: thermal desorption temperature was 300℃,thermal desorption time was 3 min,and the cold trap temperature was –10℃.In these conditions,1 mg/kg standard was added in samples,and the determination results were between 0.75 and 0.94 mg/kg,and the relative standard deviations were 2.89% –7.16%.

White sugar and crystal sugar were dissolved directly by distilled water, and then were titrated the content of sulfur dioxide by iodine standard liquid. Take six samples to compare with the distillation method of GB/T5009.34—2003, the results were in good agreement. Repetition experiment was tested for three samples. Their relative standard deviations were 2.5%, 2.6% and 3.0%. The method is accuracy, reliability, simple, fast and easy to operate, the detection line is low. Especially, it is suitable for rapid determination of residual sulfur dioxide in mass white sugar and crystal sugar and provides the method to the market supervision monitoring for rapid detection.

目的:了解广西市售龙眼(荔枝)干、桂圆肉、保鲜龙眼中SO2的残留情况,为市场监管部门加强食品安全监督提供参考.方法:2010年-2012年随机抽取广西市场上的保鲜龙眼、龙眼(荔枝)干、桂圆肉64个样品,按GB/T5009.34-2003《食品中亚硫酸盐的测定》第二法测定SO2残留量.结果:符合国家卫生标准的43份,合格率67％,其合格率从高到低依次为保鲜龙眼(100％)＞龙眼干(75％)＞荔枝干(69％)＞桂圆肉(50％).结论:广西市售龙眼(荔枝)干、桂圆肉中,超国家卫生标准的达33％,不同程度地存在SO2残留量超标的情况,桂圆肉中最高SO2残留量超国家卫生标准8.6倍.

The seventeen volatile organic compounds(VOCs) in soil were detected by thermal desorption-cold trap-GC-MS,and the standard curves were drawn by the seventeen VOCs(halogenated hydrocarbon and benzene series) as standards.The correlation coefficients of every compounds were 0.9973~0.9998;the detection limit were 0.02~0.13μg/kg;the recovery rate were 85.2%~98.5%;the RSD were 3.17%~5.56%.The advantages of the method were short analysis time,simple operation,high sensitivity,and the results were satisfactory.

The method for the determination of inorganic arsenic(AsV,As Ⅲ),organic arsenic(DMA,MMA,AsB)in seafood by HPLC–AFS was established.The samples were surged and distilled with a mixed solution of 10%(volum ratio) HCl,separated in a centrifuge,then As(Ⅲ),DMA,MMA,As(V)were determined by second road speciation analysis of pretreatment device and HPLC–AFS;AsB was determined by four road(hydrogen peroxide oxidation and UV light was turned)speciation analysis of pretreatment device and HPLC–AFS.The linear range was 0–100.00 μg/L for As(Ⅲ),DMA,MMA,A(s V);0–200.00 μg/L for AsB,and correlation coefficients r2were 0.999 7,0.999 3,0.999 0,0.9991,0.999 4 respectively.The three samples recoveries were 86.7%-89.4% for As(Ⅲ),111.2%–117.0% for DMA,109.7%–111.6% for MMA,83.8%–90.7% for AsV,88.3%–90.4% for AsB.The relative standard deviation of determination results of shrimp(dry) samples of 5 valence states was 3.07%–9.93%(n=6),and detection limit(S/N=2) of the method were 0.29,0.36,0.27,0.56,1.46 μg/L for As(Ⅲ),DMA,MMA,As(V),AsB,respectively.The method is suitable for determination of As(Ⅲ),DMA,MMA,As(V),AsB in seafood.

An assessment was carried out to determine the sulfur in soil by high frequency infrared absorption spectrometer,and the sources of uncertainty in this analytic method was analyzed such as standard materials,weighing,duplicate test,instrument showed value,fluxing agent and porcelain crucible etc.The mathematical model was established and the standard uncertainty components were calculated.The results showed that combined standard uncertainty was 0.00073% and extend standard uncertainty was 0.0015%.The sources of uncertainty came mainly from duplicate test and selected standard materials,whereas the uncertainty from instrument showed value could be ignored.It was necessary to control weighing,fluxing agent and porcelain crucible during the measurement.

Formaldehyde,benzene,total volatile organic compounds(TVOC),ammonia,radon in indoor air were determined in 30 residential buildings and 5 office buildings after decorating in Guangxi Nanning city.The results showed that TVOC exceed the national standard more than any other item,samples overstep percentage in residential buildings such as sample point was 67.2% and sample unit was 80.0%,in office building was 15.2%;TVOC overstep percentage in residential building dissimilarity function such as living room was 58.6%,in bedroom was 60.7%,in reading?room was 80.8%,in kitchen was 55.6%.The research indicated decorating related indoor environmental severe contamination,mostly resulted in indoor air quality declining.Finally some countermeasures of prevention and suggestions were promoted to solve the problem.

In soil sample,volatile organic compounds(VOCs) is easily volatilized and the residual concentration of it is low. Thus,it is essential to use suitable way to extract.The paper discusses previous way to extract VOCs and summarizes the current extraction methods and its development tendency.

The fresh fruit samples were dissolved with a mixed solution of HNO3-H2O2(4+2) by microwave digestion,and the amount of sulfur in the samples solution was determined by ICP-AES.Wavelength of 182.0nm was selected as analytical spectral line.Detection limit(3Sd) of the method was 0.065mg·L-1,and the relative standard deviation(n=8) was 1.90%.The proposed method was used in determination of sulfur in 2 national standard samples(standard reference materials tea GBW 10016 and apple GBW 10019),and the obtained results were in conformity with standard values.The results of measurement were in good agreement with those obtained from the proposed method and barium sulfate gravimetric method.The samples recovery(n=8) was between 100% and 102%.

128 samples of granites of decorative building materials from 5 cities in Guangxi were gathered,and the parameters such as specific activity,internal exposure index and external exposure index of 226Ra,232Th,40K were measured by gamma spectrometer.According to measured results,level A was 115 samples accounting for 89.8%,level B was 11 samples accounting for 8.6%,level C were 2 samples accounting for 1.6%.The analysis result showed that mostly granites were safe which can be directly used for interior decoration,but about 10% granites were unsafe.

Industrial waste is more and more comprehensively utilized in the production of building materials.This can easily result in the change or increase of the radioactivity of building materials,if the natural radionuclide of industrial waste mixed is high.In this paper,a mathematical model of the radioactivity of building material products mixed with slag was established by applying the simplex grid-point design and program solution of Excel.Based on the experimental data and regression equation,a proportioning optimization and the internal law between main index and mixing materials factors were founded.This work provides an important reference for the determination of the formula of the building material products mixed with slag and the control of radioactivity.

The radioactive strength of building materials effected by factors,such as amount of industrial waste slag, and sin- tering temperature, was studied. The objective is to find the effective way to reduce the harmful radiation of building materials, and to discuss the rational utilization of industrial waste to produce the products of building materials in the range of safety radi- ation. The results indicate that the radioactivity of fly ash through high-temperature treatment increases with temperature rises;but the radioactivity and internal and external exposure index of sintered products of mixture of industrial waste reduced evidently. Proper ingredients can make sintering products to meet Class A building materials of the state standard. At high-temperature,some molten oxides in the waste slag and clay minerals formed the sinter,radioactive materials introduced industrial waste can be par- tially absorbed by the sinter,radionuclide particles can be wrapped up by sinter,so that the shielding effect of sinter reduce the intensity of its radiation.

目的 通过对广西建筑主体材料放射性进行检测与评价,为广西建筑主体材料的合理生产与应用提供参考依据.方法 依据国家标准<建筑材料放射性核素限量>(GB6566-2001)进行检测.结果 广西建筑主体材料除了部分煤渣砖超标外,页岩砖、粘土砖、水泥、砌块和混凝土等材料的内、外照射指数水平均符合国家标准.但在对不同类型的建筑主体材料检测中发现,部分页岩砖、粘土砖及复合水泥的放射性水平含量相对偏高.结论 广西大部分建筑主体材料可不受限制地应用于各种建筑工程中.

使用热重分析仪对煤进行工业分析,在一定条件下,以百分失重率一次性获得煤的水分、挥发分、固定碳和灰分的含量.

对采用超高压烧结工艺,在不同烧结温度(保温时间均为240s)下制作的Si3N4陶瓷,用X射线衍射仪对其相结构变化进行了分析研究,发现超高压烧结的Si3N4陶瓷可以在较低温度下瞬间完成从α相向β相的转变过程.

通过改装马弗炉为试验用炉,用热电偶同时测定复合防火玻璃的受火面和背火面温度.测试结果表明,该方法简单易行,且能较好地满足复合防火玻璃耐火性和科研试验等测试要求.

陶瓷的烧结温度与陶瓷的强度、韧性以及断口形貌密切相关.我们对超高压烧结Si3N4陶瓷断口形貌与烧结温度的关系进行了研究.