沉淀浮选铜光度法测定头孢曲松钠

建立了沉淀浮选铜测定头孢曲松钠的新方法。研究表明:pH4.0,头孢曲松钠的降解产物中的巯基能将Cu(Ⅱ)还原成Cu(I),所生成的Cu(I)与降解产物中的巯基生成白色乳状硫化物沉淀。通过测定溶液中剩余Cu(II)的吸光度,可以间接测定头孢曲松钠的含量。线性方程:A=4.803+0.0886ρ(μg/mL),线性范围为0.60～35μg/mL,相关系数r=0.9996,表观摩尔吸光系数ε=5.1×104L·mol-1.cm-1。方法已用于测定头孢曲松钠注射剂中头孢曲松钠的含量。     

丙醇-水体系萃取浮选铜光度法间接测定硫离子

研究表明,Cu(Ⅱ)与 S2-形成CuS沉淀,在丙醇与水分相过程中,能被浮选于丙醇/水两相界面之间.Cu(Ⅱ)浮选率与S2-的量之间存在着良好的线性关系,据此建立了间接测定痕量S2-的新方法,线性范围2.2×10-8～3.2×10-6 g/mL,检出限为1.6×10-8 g/mL.常见多数阴、阳离子均不干扰测定,可用于污水与温泉水中痕量S2-的测定.     

丙醇-水体系萃取浮选铜间接测定硫氰酸根

试验表明, 在SCN-存在下, Cu(Ⅱ)能被抗坏血酸还原为Cu(Ⅰ), Cu(Ⅰ)与SCN-形成CuSCN沉淀, 该沉淀在丙醇与水分相过程中, 能很好的浮选于丙醇/水界面之间, 通过测定Cu(Ⅱ)浮选率, 能间接测定SCN-的量, 据此建立了测痕量SCN-的新方法, 多数常见阴、阳离子不干扰测定. 测定的线性范围为3.0×10-6～7.8×10-5 mol/L, 检出限为1.5×10-6 mol/L, 回收率为95.7%～103%. 用于尿样与唾液中SCN-的测定.     

溶剂浮选光度法测定痕量铜

提出了利用溶剂浮选富集ＤＤＴＣ－Ｃｕ（Ⅱ）体系测定水样中痕量铜的方法（ＤＤＴＣ为二乙胺二硫代甲酸钠）。质量浓度的检出限为０．０５ｎｇ·ｍＬ＾－１,线性范围为０．０￣６．０ｎｇ·ｍＬ＾－１,测定含Ｃｕ（Ⅱ）４．０ｎｇ·ｍＬ＾－１的样品,相对标准偏差为０．８５％,已用于天然水中Ｃｕ（Ⅱ）的测定。     

异丙醇-硫酸铵-水体系浮选硫氰酸亚铜法间接测定硫普罗宁

研究表明:控制溶液pH4.0,在SCN-存在下,Cu(Ⅱ)被硫普罗宁分子中的巯基(SH)还原生成的Cu(Ⅰ)与SCN-形成CuSCN白色乳状沉淀。该沉淀能被浮选在异丙醇/水两相界面之间。通过测定溶液中剩余Cu(Ⅱ)的量,从而间接测定硫普罗宁的量。硫普罗宁测量的线性范围0.30～12.0mg/L;检出限为0.20mg/L。本方法可直接用于片剂、血清、尿样中硫普罗宁含量的测定,结果满意。     

电荷转移褪色光度法测定头孢哌酮钠的含量

利用荷移反应测定药物的含量，近年来已有广泛的应用。本文研究了头孢哌酮钠和苯基荧光酮在甲醇介质中的电荷转移反应，该反应为褪色反应，确定了最佳反应条件，与文献方法相比，具有方便、快捷、重复性好等优点。     

溶剂浮选分光光度法测定痕量铜

在酸性条件下，Cu(Ⅱ)-SCN－结晶紫形成很深颜色的三元离子缔合物，通过浮选富集，在587nm处测其在有机溶剂中的浓度，建立了测定痕量铜的新方法。该法用于测定环境水样和经处理的茶多酚中的铅含量．摩尔吸光系数达1．68×106L.mol-1．cm－1，线性范围0．50～60μg／L。回收率为99．4％～101．2％，结果令人满意。     

单一试剂光度法测定血清铜

建立了一种非离子型表面活性剂吐温 80 (Tween 80 )及聚乙二醇辛基苯基醚 (OP)存在下 ,用 2 ( 3 ,5 二溴 2 吡啶偶氮 ) 5 二甲氨基酚 ( 3 ,5 diBr DMPAP)作显色剂直接光度法测定血清铜含量的新方法。用该法测定血清铜 ,显色络合物最大吸收波长为 5 74nm ,线性范围达 63 0μmol·L- 1,表观摩尔吸光系数为 6 91× 1 0 4 L·mol- 1·cm- 1。回收率为 97 2 %～ 1 0 1 5 % ,批内和批间变异系数 (CV)分别为 2 7%与 3 8% ,与原子吸收分光光度法比较相关性良好 ,y =0 98x +0 43 ,r=0 9993 ,P >0 0 5 ,42例健康人血清铜含量为 8 3～ 2 4 9μmol·L- 1( x± 2s)。用该法进行血清铜含量测定 ,准确性和重现性均较好 ,且血清用量少 ,不必去蛋白 ,操作步骤简化 ,具有试剂单一稳定 ,操作简便快速 ,结果灵敏可靠等优点 ,适合临床应用。     

溶剂浮选-间接光度法测定抗坏血酸

于pH 7.0的磷酸盐缓冲介质中,CTMAB＋及I3-离子间借静电引力形成离子缔合物,可将其浮选入5.0 mL苯中,此缔合物在溶剂中,于365 nm处有吸收峰,较简单的I3^-离子在相同条件下的吸收峰（350 nm）红移了15 nm。在此溶液体系中存在抗坏血酸时使离子缔合物产生褪色反应,且在抗坏血酸浓度在25μg/50 mL以内时与吸光度的降低值（ΔA）间呈线性关系。在抗坏血酸浓度为6.0μg/50 mL时连续测定6次,所得结果的RSD为1.2%,回收率在96%-101%之间。     

Indirect determination of cefradine with n-propyl alcohol-ammonium sulfate-water system by extraction-flotation of cuprous thiocyanate

A new method was developed for the determination of cefradine by extraction-flotation of CuSCN.The experiment indicated that in the presence of 0.20 mol/L NaOH the degradation of cefradine took place in water bath at 100℃.The thiol group(-SH)of the degradation product could reduce Cu(Ⅱ)to Cu(Ⅰ)for the formation of the emulsion CuSCN in the presence of NH_4SCN at pH 4.0.By determining the residual amount of Cu(Ⅱ)in the solution and calculating the flotation yield of Cu(Ⅱ),the indirect determination of cefradine can be obtained.This method has been applied to determine cefradine in capsules,human serum and urine samples,respectively.     

Coefficients of caffeine distribution in aliphatic alcohol-ammonium sulfate-water systems

The extraction of caffeine with aliphatic alcohols C₃?CC₉ from aqueous solutions in the presence of a salting-out agent (ammonium sulfate) is studied. Quantitative characteristics of extraction are calculated: the distribution coefficients (D) and the degree of recovery (R, %). Relations are found between logD of caffeine and the length of the hydrocarbon radical in the alcohol molecule, along with certain physicochemical properties of the extragents.     

Spectrophotometric determination of trace copper with a Cu-diethyldithiocarbamate-beta-cyclodextrin colour system

A simple, selective and accurate spectrophotometric method for determination of trace copper with diethyldithiocarbamate(DDTC) in the presence of beta-cyclodextrin(beta-CD) in ammonia media has been developed. The apparent molar absorptivity of Cu(II)-DDTC-beta-CD inclusion complex is 1.3 x 10(4) 1 . mole(-1) . cm(-1) at 436 nm, and Beer's law is obeyed for copper in the range 0-150 mug/25 ml. The detection limit is 4.38 x 10(-7)M(S/N = 3). The proposed method has been successfully applied to the determination of copper in aluminium alloys, soils, millet, wheat flour, herbs, vegetables and some traditional Chinese herbal medicines with satisfactory results.     

Spectrophotometric determination of copper with cuproine

A study is devoted to the spectrophotometric determination of traces of copper with cuproine as reagent. After having determined the absorption spectrum of the complex, the authors have studied successively the partition coefficient water/ isoamyl alcohol ; the stability of the complex (colour); the influence of some factors: pH, foreign ions, temperature, the quality of isoamyl alcohol, excess reagent; and the validity of Beer's law. Two different calibration curves were determined, one based on complete extraction of the complex and the other based on an empirical method, which is very rapid. In both cases the mean square error is less than 1%.Finally, analysis methods were worked out for the determination of traces of copper in plants, animal tissues and blood, in water, in lamp-black and in steel.     

Spectrophotometric determination of copper with tiron

The reagent Tiron forms a soluble greenish-yellow complex with cupper. The sensitivity of the colour reaction is 0.24 mμ of copper/cm₂. The colour system at a pH of 6.1 to 6.9 is stable for over 24 h and shows a maximum absorption at 375 mμ. It obeys Beer's law at the latter wave length within a copper concentration of 10 to 160 p.p.m. The optimum range, however, is from 50 to 160 p.p.m. of copper, where the percent relative analysis error per 1% absolute photometric error is 2.94. JOB's method of continuous variation and the molar ratio method of YOE et al.² indicate that in solution the complex contains the metal and the reagent in a ratio of l : 2, with a dissociation constant on the order of 5.3 ? 10^-6.     

Spectrophotometric determination of copper with uramyldiacetic acid

A new method for the spectrophotometric determination of copper using uramyldiacetic acid as chromogenic reagent is proposed. The complex is formed in a wide pH range (2.5–9); but in order to avoid the potential conversion of UDA in murexide it is convenient to work at pH < 3: and has a maximum of absorption at 775 nm. Beer's law is obeyed in the interval 20–420 μg of copper(II)/ml. The Ringbom optimal range falls between 70 and 400 μg of copper(II)/ml, with a minimum photometric error of 2.8. The reaction between the metal and the ligand takes place in the ratio 1:1. The method has been applied to the determination of copper in ores with low content of the metal.     

Spectrophotometric determination of copper with hydrochloric acid

A procedure is proposed whereby copper may be determined spectrophotometrically by means of the very near infrared absorption of its complex ion with hydrochloric acid. Only stannous and ferrous ions are serious interferences and they may be oxidized with nitric acid or with ammonium persulfate to avoid such interference. The method is simple and rapid and is capable of reasonably good precision and accuracy.