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通过对样品进行加热浓缩和赶氨处理,改进了测定含氨样品中缩二脲的方法,其分析周期由原来的6h降至1h以内,此方法检出限较低,精密度好,准确度高,操作快速简便。 相似文献
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测定缩二脲含量时,在尿素工艺物料样品的除氨处理过程中不使用有毒的甲醇试剂,而是在样品中加入乙醇,在一定温度条件下通入氮气汽提氨。试验证明,改进后的尿素工艺物料中缩二脲含量的测定过程更加简便、快速、准确,样品测定时间由6h缩短至1h。 相似文献
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通过搭建装置,模拟《QB/T 2761-2006室内空气净化产品净化效果测定方法》,测定被动式空气净化产品的除氨效果。该装置由氨气发生装置、除氨装置和氨气收集装置组成。实验时在氨气发生装置中加入5.0 mL浓度为25%的浓氨水作为氨源,用滤纸作为样品载体,取3.0 g样品加于滤纸上,通过附有样品的滤纸吸收氨气后,采集剩余氨气并使用酸碱滴定法测定被吸收氨气量,通过计算空白样品和待测样品吸收氨气量的差异,从而得到样品除氨率。分析测试4个不同样品,结果稳定性良好且与行标方法接近。该方法具有设备简单,占地面积小,氨含量测定时不需要用到有毒有害物质,分析结果准确等特点。 相似文献
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尿素复合肥中,有含氨态氮和硝态氮的,也有含氨态氮和尿素氮的。目前,对于前一种氨态氮的测定,一般用蒸馏后滴定法,但对于后一种氨态氮的测定,国内尚未有十分明确的检验方法。用蒸馏后滴定法由于碱性太强,蒸馏温度高,导致尿素的分解,测定结果偏高;用甲醛法由于PO_4~(3-)的缓冲作用,使终点拖延,酚酞变色推迟,测定结果也偏高;通空气冷蒸馏法是国际标准方法和欧共体使用的方法,但耗时较长(2~3h),易使蒸馏不完全,结果偏低。因此,我们采用了减压蒸馏法测定含尿素的复合肥样品中的氨态氮。用 相似文献
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《日用化学工业》2019,(11)
建立了美白类化妆品中氨甲环酸的高效液相色谱测定方法。采用5%甲醇溶液对化妆品样品中的氨甲环酸进行提取。样品用Shiseido CAPCELL PAK C_(18) UG120色谱柱(4.6 mm×250 mm,5μm)分离,以甲醇与0.05 mol/L KH_2PO_4-0.2%H_3PO_4溶液(体积比为5∶95)为流动相,流速为1.0 mL/min,检测波长为210 nm。结果表明,氨甲环酸在5~100 mg/L范围内线性关系良好,相关系数(r)大于0.999。在各化妆品基质中方法检出限为10.7~22.2μg/g,方法定量限为28.9~48.0μg/g。回收率为95.23%~110.40%,RSD值为1.24%~3.59%(n=6)。日内稳定性良好,在24 h内峰面积RSD值为0.026%。该方法简便、可靠,可作为美白类化妆品中氨甲环酸的含量测定方法。 相似文献
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采用后合成法将3-氨丙基三甲氧基硅烷嫁接在纯硅介孔分子筛KIT-1的孔道内外表面,制备出含氨丙基基团的介孔分子筛样品NH2-KIT-1,并用于苯甲醛和丙二酸二乙酯Knoevenagel缩合反应。利用傅里叶变换-红外光谱(FT IR)、X射线粉末衍射(XRD)、N2吸附-脱附和酸碱滴定等方法对样品的结构和表面碱含量进行了表征与测定。结果表明:氨丙基已成功嫁接在分子筛KIT-1表面,样品NH2-KIT-1仍保持了基体KIT-1的介孔结构和较高的比表面积、较大的孔容与孔径。表面碱含量为1.105 mmol/g样品(即30%NH2-KIT-1)在苯甲醛和丙二酸二乙酯Knoevenagel缩合反应中表现的催化活性最好,140℃反应12h,苯甲醛的转化率为66.5%,重复使用4次后,苯甲醛转化率下降到46.9%,表面碱含量下降到0.870mmol/g。催化剂活性下降的原因可能是分子筛表面活性基团-(CH2)3-NH2脱落造成的。 相似文献
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通过对样品加热浓缩,达到除氨的效果,从而进一步提高了含氨样品中缩二脲含量测定的准确度、精密度,更适合现场快速分析需要。 相似文献
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V. I. Ekgauz K. V. Pokryshkin G. D. Tretiakova N. V. Dementieva L. A. Stepina A. V. Putilov N. K. Motovilova O. V. Ryazanov A. V. Kalinin M. I. Blokhin A. V. Grakhovskiy I. V. Sorokina 《Coke and Chemistry》2016,59(3):92-100
The industrial introduction of ammonia removal from coke-oven gas by the circulatory phosphate method at byproduct shop 2 in coke production at PAO Severstal’ is considered. The ammonia removed undergoes thermal decomposition. The system consists of three channels (including a backup) and is designed to process coke-oven gas at a rate of 170000 m3/h. The phosphate method is selected after comparing methods of ammonia removal. The startup and operation of the system are analyzed. Operating conditions corresponding to specified ammonia removal are selected. Data are presented regarding the ammonia absorption, the regeneration of the absorbing solution, the thermal decomposition of the steam–ammonia mixture, and the utilization of the smokestack gas from the combustion of the steam–ammonia mixture. With a design productivity of 85000 m3/h for a single channel, the system operates satisfactorily when the throughput of coke-oven gas is in the range 60000–130000 m3/h per channel. 相似文献
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研究了水样中所含甲醛对测定微量氨的影响情况,并采取了对水样酸性加热除甲醛的办法,消除了甲醛对测定微量氨的影响,提高了测定微量氨的准确度,测定结果的相对偏差从20%以上降至<1%以下。 相似文献
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在磷酸盐缓冲溶液中加热蒸馏三聚氰胺废水样品,逸出的氨被吸收后通过酸碱滴定测定其含量。该 方法抗干扰能力强,准确度高,完全能满足监测三聚氰胺装置废水中氨含量的需要。 相似文献
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Frank Lucus Steinkamp Braden Giordano Greg Collins Susan Rose‐Pehrsson 《Propellants, Explosives, Pyrotechnics》2015,40(5):682-687
Ammonium nitrate (AN) is an ionic solid commonly used as a fertilizer and in commercial blasting applications. Frequently, AN is mixed with a fuel and used in improvised explosives devices (IEDs). To characterize the low‐volatility components emanating from AN, a sample of AN was sealed inside a stainless steel chamber while a laminar flow of air swept the headspace vapor components into a water impinger or cold‐trap for pre‐concentration and subsequent analysis by ion chromatography (IC). Both collection methods were found to be 100 % efficient for collecting nitric acid vapor, whereas the collection efficiency for ammonia was dependent upon the collection method and, for the water impinging method, additionally upon the vapor concentration, humidity and flow rate. Cold‐trapping efficiency for ammonia was 4 %±2 % across all parameters studied. Water impinging was more efficient (20–70 %), but the efficiency varied according to each of the aforementioned variables. The characteristics of an AN vapor generated from a solid sample were found to vary as the sample approached equilibrium inside the chamber. Initially, large quantities of ammonia were observed, but as a steady state was achieved within the laminar flow and a dynamic equilibrium established, the ratio of ammonia to nitric acid in the effluent vapor dropped, although never becoming equimolar. The ratio was strongly dependent upon humidity. 相似文献
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锌基复合镀层中含氮聚合物的定量分析 总被引:1,自引:0,他引:1
采用微量基耶达法将有机氮以无机氮的形式从锌基复合镀层中分离出来,然后用滴定法对氨进行定量分析,进而计算出样品中含氮聚全物的含量,实验操作简便,测量精度高,相对标准偏差小于6%。 相似文献
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电解铜样品经硝酸溶解,所得样品溶液中的铜离子在过量氨水中生成可溶性铜氨络离子,而电解铜中的铋则以氢氧化铁作载体共沉淀,实现了富集铋,经过滤分离铜后,用稀盐酸溶解沉淀于容量瓶中,选择223.1nm谱线作为分析线,通过火焰原子吸收光谱法测定电解铜中的铋,与碘化钾分光光度法进行了对照,结果一致。 相似文献