建立高效液相色谱-电喷雾串联质谱法检测牛奶中土霉素、四环素及金霉素残留的分析方法.采用酸化乙腈提取样品并沉淀蛋白,离心、浓缩、正己烷脱脂,经Agilent ZOBAX SB-C18柱分离,以0.1％甲酸-乙腈对待测成分进行梯度洗脱.采用高效液相色谱-串联质谱多反应监测正离子模式检测,外标法定量.结果表明,3种抗生素浓度在50～1 000μg/L范围内线性关系良好,方法定量限(LOQ,S/N=10)为15～25 μg/kg,检出限(LOD,S/N=3)为8～15μg/kg,加标回收率为79.6％～～88.7％,相对标准偏差为3.2 ％～6.0％.该方法前处理简单、可靠,灵敏度高,适用于牛奶中四环素类抗生素残留的快速测定.

This experiment was conducted to study the effect of dietary lipid level on the digestive enzyme activities of juvenile Onychostoma sima.The fish of with average initial body weight of(0.78±0.05)g were fed the feed that of lipid level was 2.83%,4.52%,6.68%,9.14%,11.35% and 14.07%,respectively.The experiment lasted for 60 days.The results showed that there were significantly effects of dietary lipid level on digestive enzyme activities of juvenile Onychostoma sima.The protease in intestine increased with the increase of dietary lipid levels,but there were no significant difference when the dietary lipid level more than or equal to 9.14%(P0.05).The activities of protease in hepatopancreas were no significant difference when the dietary lipid level less than 9.14%,but those were significantly decreased when the dietary lipid level more than 9.14%(P0.05);At the same time,the lipase in intestine increased with the increase of dietary lipid levels,the lipase in hepatopancreas first increased then decreased as the level of dietary lipid increased,and its where highest.when the dietary lipid level was 9.14%(P0.05)the activities of amylase in foregut were not change significantly(P0.05);The activities of amylase in midget first increased then decreased as the level of dietary lipid increased(P0.05),the activities of amylase in hindgut slightly decreased with the increase of dietary lipid levels,the activities of amylase in hepatopancreas first increased then decreased as the level of dietary lipid increased,but there were no significant differences(P0.05).Results of above show that the dietary lipid level could promote the digestive enzyme activities and improve the feed utilization of Onychostoma sima

The influence of the determination of the composition of liquor characteristic components by gas chromatography,such as the gas chromatography column,solvent,sampling methods,quantitative methods and other aspects,was analyzed and discussed.The results showed that the stationary phase of the gas chromatography column Significantly influenced the sequence of the characteristic components at the chromatogram,and improper selection of the gas chromatography column would cause the errors of the quantitative analysis results.The solvent would make peak order change,and then lead to qualitatively incorrect,or maybe introduce some interference component.Sample volume and the split ratio mainly affecting the chromatographic separation.Different quantitative methods may have great influence on the quantitative results.In the process of analysis,according to the liquor testing project and objective,60% ethanol(HPLC pure) aqueous as solvent,suitable chromatography column,optimized chromatographic conditions and quantitative method should be adopted to reduce errors and provide more accurate data.

Studies have been carried out on the simultaneous determination of four parabens,i.e.methylparaben(MP),ethylparaben(EP),propylparaben(PP) and butylparaben(BP)in betelnut.The results showed that the linear correlation coefficients were higher than 0.999.Overall recoveries were 80%～100%,with relative standard deviations(RSDs) less than 4%.The detection limits for the analysis was 0.005 g/kg.The method is sensitive,reproducible,accurate and satisfactory for determination parabens in betelnut.

Three-dimensional visualization technology is widely used in medicine and industry field.This paper first introduces the concept and the importance of the three-dimensional visualization technology,describing the algorithms of three-dimensional visualization technology in three categories: surface rendering,volume rendering,point rendering.Then the VTK which is a three-dimensional visualization SDK is introduced,and an volume rendering example of Ray Casting algorithm based on VTK is proposed.In the end,the prospective developing direction of the three-dimensional visualization technology is put forward.

A capillary gas chromatography method was developed to separate and determine four para-hydroxybenzoic acid esters(methyl phydroxybenzoate,ethyl p-hydroxybenzoate,propyl p-hydroxybenzoate,butyl p-hydroxybenzoate) in foods simultaneously,for example,betel nut,pickled vegetable,etc.Samples were directly extracted with ethyl acetate without concentration,the results showed that the linear correlation coefficients were higher than 0.999.The detection limit s for the analysis were all 0.01 mg /kg(S/N=3).The average recovery is in the rang of 88.5%～103.5%,with RSD less than 10%.The method is simple and reliable.It can be used to analyze 4 p-hydroxybenzoates in foods with satisfactory results.

The copper content in candy was determined by flame atomic absorption spectrometer according to the nation standard. The source of indetermination degree in the process was considered relatively, and made a system analysis to each factor, which influence the result indetermination degree. A mathematical model was made to assess the indetermination degree, and inquiried into its measurement result indetermination a degree.

通过对15块不同类型天协1号群体主要经济性状与产量的相关和通径分析,表明在各经济性状中穗总粒数对产量的决定作用最大,其次是有效穗,再次是结实率。高产田块主要经济性状及产量的变异分析得出,天协1号单产在600kg/667m2以上主要性状95%的置信区间为:株高113.68~118.80 cm,穗长21.86~22.52 cm,密度1.92~2.06万/667m2,有效穗19.24~20.36万/667m2,穗总粒数168.84~181.59粒,结实率80.00%~84.16%,千粒重26.49~27.02g,预估单产633.48~658.40kg/667m2。

Objective:Discussing detecting method of residual aluminium in food; Methods:Digest the samples by dry process and determine the aluminium residual in food by Chrome azurol S spectrophotometric method; Results:It had good linerity under 10 μg, the regression equation was Y=0.083 1X+0.000 6(r=0.999 3).The average recovery was 97.55%,and RSD was 1.79%;Conclusion: The above method is satifactory for real specimen test.

According to evaluation and expressing of uncertainty in measurement(JJF1059-1999)and the method of analysis of the content of the reduced sugar in foods(GB/T5009.7——2003),a mathematical model was established.The independent uncertainty,standard uncertainty and expanded uncertainty coming form analysis procedure were obtained.In the paper,the method established can be used to evaluate uncertainty in measurement of content of the reduced sugar.