气相防锈纸(膜)中亚硝酸根含量的测定

为了建立科学的检测气相防锈材料中亚硝酸根含量的方法,系统地研究了试样的不同浸泡提取条件对亚硝酸根浸提量的影响,考察了浸提液的酸度、温度和浸提时间等因素.结果表明,对于气相防锈纸中亚硝酸根的测定,用pH值为8.5的无亚硝酸盐水,在60℃下浸提30min,提取量最大;而气相防锈膜需利用pH值为8.5的无亚硝酸盐水,在沸腾的条件下浸提35min,获得最大提取量.     

滴定法测定食品中亚硝酸盐含量的研究

亚硝酸盐含量的测定是食品检测中重要的检测指标之一,现行的检测方法很多。文中采用了滴定法测定食品中亚硝酸盐含量,利用亚硝酸根在酸性条件下跟碘离子反应,生成碘单质,再用硫代硫酸钠滴定法碘单质,间接测定食品中亚硝酸盐的含量。实验中还研究了淀粉用量、不同酸性物质和不同pH等反应条件对回收率的影响。最后研究了此方法测定亚硝酸盐含量的时,食品中其他物质对结果的影响。该方法测亚硝酸盐含量相对偏差为2.4%,限检量为0.30mg/kg。     

结晶紫褪色分光光度法测定亚硝酸根

基于稀盐酸介质中,亚硝酸根与结晶紫的褪色反虚,建立了测定痕量亚硝酸根的新方法。在结晶紫的最大吸收波长595nm处,方法的线性范围为0．08—2μg／mL。该方法选择性好、灵敏度高,用于火腿肠和自来水中亚硝酸根的测定,结果令人满意。     

一例气相缓蚀剂在防锈包装上的应用研究

介绍了亚硝酸二环己胺与海泡石压片的制备工艺,并以该压片为例对气相缓蚀剂在铁制品包装中的缓蚀性能进行了研究.结果表明:当压片中亚硝酸二环己胺质量分数为80%时,缓蚀效果最好,且压片只有在充分预挥发条件下,才能对金属制品达到最大的缓蚀效果.     

温度对亚硝酸型硝化/反硝化的影响

以间歇式活性污泥法（SBR）法处理啤酒废水，系统考察了温度变化对亚硝酸型硝化／反硝化的影响。结果表明：温度维持在30℃得到的亚硝酸型硝化的污泥，运行在常温（19．5－23．5℃）50周期，硝化类型转变为硝酸型硝化。而后，逐渐升温，硝化类型逐渐转变为亚硝酸型硝化。当温度达到28－29℃时，硝化类型为稳定的亚硝酸型硝化，硝化反应结束时NO2^--N/NOx^--N平均维持在82．2％－83．5％。28－29℃是本试验条件下亚硝酸型硝化的临界温度。而且不论是亚硝酸型硝化／反硝化还是完全硝化／反硝化，DO、ORP、pH在脱氮过程中的变化规律基本相同，可以作为SBR法脱氮过程的控制参数。     

丁二酮的合成与提纯

生产高收率、高纯度丁二酮是当前丁二酮研究的难点。本论文选用丁酮亚硝酸酯反应合成路线，考察了不同工艺条件下丁二酮单肟合成、水解及不同分离方法对丁二酮收率和纯度的影响并在实验条件下生产出了收率约为40％、纯度98％的高收率、高纯度丁二酮产品。实验结果表明，提高丁二酮收率的关键是提高丁二酮单肟的收率，而提高其纯度的关键是除去水分。     

含硅聚氨酯的制备及其动力学研究

以3-氨基丙基三乙氧基硅烷(KH550)、丙烯酸羟乙酯(HEA)、2,4-甲苯二异氰酸酯、对甲酚为原料,制备含硅聚氨酯.用红外光谱对反应合成过程进行跟踪测定,发现端-NCO的聚氨酯预聚物和对甲基苯酚的封端反应在无催化剂条件下为二级反应,当加入催化剂三乙胺后该反应在发生初期为一级反应.无催化剂条件下该反应的活化能为46....     

磷钼蓝分光光度法测定水质中磷酸盐的方法探讨

本文探讨了磷钼蓝分光光度法测定生活饮用水及其水源水中磷酸盐准确度的主要影响因素.研究表明:磷酸盐的测定条件在反应温度为20℃、显色反应时间为10min最佳,在该条件下,标准曲线具有良好的线性关系,相关系数在0.9994～0.9999之间,加标回收率为91.5％～105.5％,相对标准偏差2.0％～3.1％.为饮用水及其...     

二甲基烯丙基木质素季铵盐的制备及絮凝性能

以造纸黑液中的木质素为原料,通过交联反应,合成了二甲基烯丙基木质素季铵盐(DL)絮凝剂。采用FT-IR、SEM等对其进行表征,并以对酸性黑ATT的絮凝性能作为指标,通过单因素实验得出最佳合成条件。在模拟染料的条件下,测定了木质素二甲基烯丙基季铵盐对酸性黑ATT的絮凝性能,最佳温度为30℃;在pH值=1.5的条件下,酸性黑ATT的最佳脱色率对应的浓度为3.75g/L,最佳条件下测得最大脱色率为80.06%。该改性天然高分子是一种性能良好的染料废水的絮凝剂。     

低分子量肝素的制备及纯化

本文以猪肠粘膜肝素钠粗品为原料,采用亚硝酸控制解聚法制备分子量在５０００￣６０００的低分子量肝素。探索了反应温度,时间,搅拌速度,亚硝酸浓度、溶液的ｐＨ值等对解聚反应的影响。     

偶氮化合物的极谱行为及痕量亚硝酸盐测定的研究

本文研究了在氨性介质中,对氨基苯甲酸重氮盐与8-羟基喹啉形成偶氮化合物的最佳实验条件,并对电极反应机理作丁初步探讨,建立了一个灵敏、快速测定NO_2~-的新方法。大量NO_3~-存在不干扰。用于多种水样中痕量NO_2~-测定,获得满意结果,回收率为92％～100％。     

高效液相色谱串联等离子体发射质谱分析食用色素赤藓红中痕量碘化钠

建立了高效液相色谱串联等离子体发射质谱测定食用色素赤藓红中痕量碘化钠的方法,选用0.1mol/L乙酸铵溶液（pH=6.4）和甲醇为流动相,采用反相液相色谱柱ODS-C18分离了碘化钠和赤藓红,该方法的定量限与检测限分别达到10.0ng/g和 3.0ng/g,线性范围为 10~1000ng/g,精密度的范围为0.37%~0.43%,加标回收率变化范围为97.5%~99.7%。并将此方法应用到食用色素赤藓红中碘化钠的测定分析,评价了方法的不确定度。最终合成标准不确定度u_c=1.94％,扩展不确定度U=3.9%（k=2）。     

Determination of trace iodine in food and biological samples by cathodic stripping voltammetry.

This paper describes a sensitive and selective method for the determination of iodine in food and biological samples. The method involves treatment of samples by combustion in an oxygen flask and determination of iodide by cathodic stripping voltammetry of the solid phase formed with the quaternary ammonium salt Zephiramine as the ionic associating agent; Br- is used as the complexing agent in the preconcentration process. We have studied the effect of concentration of Zephiramine, Br-, I-, and some other elements presented, deposition potential, preelectrolysis time, and scan rate, on the stripping curve shape and maximum stripping current. Determinations of trace iodine in table salt, laver, and eggs were demonstrated as practical examples.     

Flame atomic absorption spectrometric determination of trace quantities of cadmium in water samples after cloud point extraction in Triton X-114 without added chelating agents

A new micell-mediated phase separation method for preconcentration of ultra-trace quantities of cadmium as a prior step to its determination by flame atomic absorption spectrometry has been developed. The method is based on the cloud point extraction (CPE) of cadmium in iodide media with Triton X-114 in the absence of any chelating agent. The optimal extraction and reaction conditions (e.g., acid concentration, iodide concentration, effect of time) were studied, and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration, and improvement factors) were obtained. Linearity was obeyed in the range of 3-300 ng mL(-1) of cadmium. The detection limit of the method is 1.0 ng mL(-1) of cadmium. The interference effect of some anions and cations was also tested. The method was applied to the determination of cadmium in tap water, waste water, and sea water samples.     

磷化液中NaNO2浓度的快速测定

提出一种快速测定磷化液中NaNO2浓度的新方法--注射器法,并成功地应用于实际样品中NaNO2的测定.该方法简单、快速,测定范围宽,相对偏差小于2%,适用于溶液中NO2-浓度的测定,特别适用于生产现场磷化液中NaNO2的监控.     

氢化物发生-电加热原子吸收光谱法测定铁精矿中砷

本文研究了采用过氧化钠溶解铁精矿,经水浸取,硫酸酸化后用氢化物技术将痕量的砷从铁精矿中分离、富集,用碘化钾、抗坏血酸和酒石酸作还原剂和掩蔽剂测定铁精矿中的砷。用标准加入电加热原子吸收光谱法消除基体效应,该方法具有灵敏度高,干扰少、快速、准确度高等优点。     

Ag/PANI/GCE电极的制备及对NO2-的电化学检测

亚硝酸盐是水中最常见的污染物之一,其检测长期以来一直是国内外研究的热点问题。制备了聚苯胺载银修饰玻碳电极(Ag/PANI/GCE)并将其应用于水中亚硝酸根的电化学检测。初步研究了亚硝酸根在电极表面的电化学行为的影响因素,并分析了所制备电极材料检测亚硝酸根的灵敏度、稳定性以及抗干扰性能。结果显示,所制备的Ag/PANI/GCE电极材料的电化学稳定性好,可以对水中的亚硝酸根浓度进行有效的检测,同时具有稳定性好、灵敏度较高、抗干扰性能强等优势,具有较高的研究价值和较好的应用前景。     

Determination of trace aluminum in biological and water samples by cloud point extraction preconcentration and graphite furnace atomic absorption spectrometry detection

A cloud point extraction (CPE) method for the preconcentration of trace aluminum prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) has been developed. The CPE method is based on the complex of Al(III) with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP), and then entrapped in non-ionic surfactant Triton X-114. PMBP was used not only as chelating reagent in CPE preconcentration, but also as chemical modifier in GFAAS determination. The main factors affecting CPE efficiency, such as pH of sample solution, concentration of PMBP and Triton X-114, equilibration temperature and time, were investigated in detail. An enrichment factor of 37 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of this method for Al(III) is 0.09 ng mL(-1), and the relative standard deviation is 4.7% at 10 ng mL(-1) Al(III) level (n=7). The proposed method has been applied for determination of trace amount of aluminum in biological and water samples with satisfactory results.