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Influence of Mixed Micelle on the Sensitized Coordination Compound of Gallium (Ⅲ) with o-Chlorophenylfluo-rone and Its Analytical Application

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After comparing the sensitizing effect of various mixed surfactants on the chromophoric reaction of gallium (Ⅱ) with orthochlorophenylf luorone, it has been found that the mixed micelle of cetyltrimethylammonium bromide and Tween-80 is most suitable. In the presence of this mixed micelle, not only both the sensitivity and stability improve markedly, but also a wider pH range is tolerable for the colour-development. From the study on the optimum conditions for the formation of the coloured coordination compoundin the system of 《Ga (Ⅱ)——o-Chlorophenyl fluorone-catyltrimethylammo-nium bromide——Tween-80》 and its main characters, a spectrophotometricmethod, by which sensitivity and reproducibility are higher than those of ternary systems of gallium(Ⅱ) has been developed. When it is combined with the dual-wavelength method, the molar absorptivity can be improved to 2.33×105 l·mol-1·cm-1,which is higher than that of most of other systems ever sh
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D0I:10.13374/i.issn1001-053x.1991.04.03M 北京科技大学学报 第13宿第4(【)期 Vol.13 No.4(I) 1991年7月 Journal of University of Science and Technology Beijing July 1991 Influence of Mixed Micelle on the Sensitized Coordination Compound of Gallium(IⅢ)with o-Chlorophenylfluo- rone and Its Analytical Application Chen Huaxu Shao Guangdi Xia Xinlong' (陈华序) (邵光约) (夏心龙) ABSTRACT:After comparing the sensitizing effect of various mixed surfactants on the chromophoric reaction of gallium (with orthochlorophenylfluorone, it has been found that the mixed micelle of cetyltrimethylammonium bromide and Tween-80 is most suitable.In the presence of this mixed micelle,not only both the sensitivity and stability improve markedly,but also a wider pH range is tolerable for the colour-development.From the study on the optimum conditions for the formation of the coloured coordination compound in the system of (Ga (I)-o-Chlorophenyl fluorone-catyltrimethylammo- nium bromide-Tween-80>and its main characters,a spectrophotometric method,by which.sensitivity and reproducibility are higher than those of ternary systems of gallium(I)has been developed.When it is combined with the dual-wavelength method,the molar absorptivity can be improved to 2.33x 1051.mol-1.cm-1,which is higher than that of most of other systems ever shown in the literatures;moreover the linear range is extended.From the determination of microamount of gallium in the copper minerals,the result is proved to be acceptable. KEY WORDS:gallium,orthochlorophenylfluorone,cetyltrimethylammonium bro- mide,mixed micelle,sensitization Although many reports concerning the chromophoric system of gallium(H) have been published in recent years,most of them are ternary systems of (Ga 1991一03一04收稿 ,化学系(Department of Chemistry) 385

第 卷第 期 年 月 北 京 科 技 大 学 学 报 了 一 “ , 夕 , , 夕 , 陈华序 邵光均 夏心龙 , 一 , 了 , 一 — 一 一 — 一 》 , , · 住 一 , 一 一 一 , “ , · , , , , , 《 一 一 收稿 , 化学 系 DOI :10.13374/j .issn1001—053x.1991.04.034

(M)-Chromophoric reagent-Sensitizer),and only few ones are quarternary systems of.《Ga(I)—Chromophoric reagent-一Sensitizer--Organic sol- vent),2.Since they always exhibit some shortcomings such as strict colour- ed conditions,less selectivity or narrow linear range ctc;so that their application are limited.In consideration of using the mixed micelle of a cationic surfactant and a nonionic surfactant has been proved to improve many chromophoric conditions of some metalss,but they have not yet been reported anywhere about the respect of gallium.In view of the fact that the sensitive chromophoric characters of phenylfluorone and its derivatives as well as their sensitive colouration with gallium()in the presence of cetyltrimethylammo- nium bromide alone had already reported+-),a study to develop a more satisfactory spectrophotometric method for the determination of microamount of gallium in the presence of mixed micelle seems to be necessary and possible to proceed. 1 Experimental 1.1 Reagents and Apparatus Stock solution of Ga(),300ug/ml,was prepared by dissolving 0.2016g of Ga2O3 (spectroscopically pure)in few ml of 1:1 hydrochloric acid by care- fully heating,then cooled the solution to room temperature and diluted it with 1:1 hydrochloric acid to 500.00ml.A working solution of Ga(),3.0ug/ml, was prepared from stock solution by diluting with 1:1 hydrochloric acid. Orthochlorophenylfluorone (o-CIPF)solution,1.0x 10-3mol/l,was pre- pared by dissolving 0.174g of solid o-CIPF in a mixture of 1:1 hydrochloric acid and 20ml of ethyl alcohol,and then diluting with ethyl alcohol to 500.00 ml in a brown volumetric flask. Cetyltrimethylammonium bromide (CTMAB)aq.solution,1.0x 10-3mol/l, was prepared by dissolving 1.82g of CTMAB with water to 500ml;if some insolubles appear,it could be dissolved by warming. Tween-80,10%(v/v)aq.solution. Phosphate buffer solution,0.2mol/l,was prepared by dissolving 27.3g potassium primary phosphate with 900ml of water,and adjusted its pH to 7.2 with an acidimeter by dropping sodium hydroxide solution,then diluted to 1000ml. 752-C UV spectrophotometer,calibrated with a Shimadzu UV-3000 spectro- photometer. Electrophoresis apparatus. 386

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1.2 Procedure 1 drop of p-nitrophenol solution is added to an aliquot of 1.00ml of Ga (working solution and then few drops of dilute sodium hydroxide solution are added until the solution to be just yellow.Subsequently 2.5ml of CTMAB solution,4.0ml of Tween-80 sofution,0.6ml of o-CIPF solution and 6.0ml of buffer solution are added according to proper order,then dilute it to 25.00ml. Measure the absorbance at 578nm against its reagent blank as reference after the mixture was placed aside for 10min. 2 Results and Discussions 2.1 Absorption Spectra After comparing the coloured sensitivities of Ga()with phenylfluorone, o-nitrophenylfluorone and o-chlorophenylfluorone,it has bcen found that the laiter is most sensitive,so that o-CIPF is chosen as the chromophoric reagent. Since o-CIPF may crystalize out in the absence of micelle under the experi- mental conditions,so that the formation of binary coordination compound in the system of (Ga()-0-CIPF)has difficulty.In the presence of micelle, especially the mixed micelle,the coloured coordination compound forms easily and stably.From the laboratory data,it has been found that the absorption 0.4 0.6 0.3 0.4 0.2 0.2 0 0.2 0.4 0.6 0.8 1.0 0-CiPF/ml 2 4 5 500 540580 620 Wave length/nm C1MA6 Or Tween 60/mL Fig.1 Absorption spectra Fig.2 Effects of the amounts of o-CIPF, curve 1.coordination compound against CTMAB and Twcen-80 reagents blank, curves:1.o-CIPF(10-3 mol/1), curze 2.reagents blank against water 2.CTMAB(10-2 mol/1), concentrations:Ga()=J.72x 10-6 mol/1, 3.Twcen-80(10%). CTMAB=10-3mol/1, all these conditions are same as Fig.1, 0-C1PF=2.4×10-5mol/1, except the variables Twcen-80=1.6% l=1c1,pH=7,2: 387

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peaks of o-CIPF and its coordination compound with Ga(I)is only 48nm apart in the presence of CTMAB micelle alone.Although the absorption peaks of both o-CIPF and its coordination compound with Ga(I)all shift batho- chromically in the presence of mixed micelle of CTMAB and Tween-80,but they situate at 530nm and 578nm respectively and their separation still remains at 48nm.The laboratory data are shown in Fig.1. 2.2 Optimum Chromophoric Conditions (1)Acidity:In the presence of CTMAB alone,a maximum and constant absorbance is obtained within the pH range of 7.2~7.6;but in the presence of mixed micelle of CTMAB and Tween-80,it is extended to pH 6.8~7.6; furthermore,its sensitivity is improved. (2)Amount of o-CIPF:To cause a maximum and constant absorbance, 0.3~0.5ml of o-CIPF solution is suitable for the ternary system of (Ga(I) -o-CIPF-CTMAB)but it is extended to 0.4~0.8m1 for the quarternary system of《Ga(I)—o-C1PF—Tween--80》. (3)Choice of surfactants:The sensitizing effect of 16 kinds of cationic and 8 kinds of nonionic surfactants have been tested.It has been found that the cationic surfactants shows obvious sensitization for the colouration of Ga (I)with o-CIPF,especially the CTMAB is most effective.After comparing various nonionic surfactants which belong to Triton X series,Tween series and emulsifier,it is found that the addition of Tween-80 to CTMAB can intro- duce a most sensitive colouration;moreover,it shows wider chromophoric conditions and better stability than with CTMAB alone. From the laboratory data shown in Fig.2,it has been found that the suitable amount of CTMAB solution and Tween-80 solution for 25.00ml of coloured solution should be 1.0~7.0ml and 3.0~6.0ml respectively.In the following experiments,2.5ml of CTMAB solution and 4.0ml of Tween-80 solu- tion are chosen;thus,a concentration of CTMAB is larger than the C.M.C. value of CTMAB alone. (4)Order of reagents adding:If the working solution of Ga(I)is mixed with o-CIPF before the presence of micelle,the absorbance is reduced.Besides, if the working solution of Ga()is mixed with buffer solution at first,the absorbance decreases markedly with the hydrolysis of Ga(),and reproduci- bility is also poor.Only after the micelle of one or two surfactants has already existed,will the colouration develop with a maximum and constant absorbance,.The order of“Ga(I)—CTMAB-Tween-80一o-ClPF buffer"has been proved to be most suitable for a rapid and complcte coloura- tion. 388

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2.3 Main Characters of Coordination Compound in the System of (Ga()- o-CIPF-CTMAB-Tween-80) (1)The colouration of this system develops at room temperature and a maximum and constant absorb:.nce can be reached after 10min.At higher temperature the absorbance will be reduced. (2)The absorbance of this system remains stably at room temperature at least within 12h,so that it is'proved to be more stable than various ternary systems. (3)By the method of molar ratio,method of equilibrium shift and method of straight linc,it has been shown that the composition ratio of Ga:o-CIPF is1:2. (4)By the test of electrophoretic property,it has been observed that the coloured coordination compoundm igrates toward the anode.Besides,the colour- ed coordination compound can be adsorbed by the anionice xchanger.Hence the coordination compound should be charged negatively. 3 Analytical Application 3.1 Influence of Foreign lons From Table 1,it is shown tuat the high valent ions and Al(),Cu(I), In(I)interfere seriously.By the solvent extraction with butyl acetate, most of the interfering metal ions can be removed and the residual small amo- unts will not interfere again.From the laboratory data,conclusion can be drawn that the co-existence of 700 fold Bi,Zn,Cu,Al or Fe;170 fold Mo, W or Zr;and equal amount of In do not interfere the spectrophotometric determ ination of microamount of gallium after their prior separation by the solvent extraction with butyl acetate. 3.2 Spectrophotometric Determination of Microamount of Gallium When the gallium is determined by mono-wavelength method,Beer's law is obeyed over a concentration range of 0~5.0ug/25ml of gallium,and the molar absorptivity is 1,66x1051.mol-1.cm-.Since the absorption peak of the coloured coordination compound is not situated away from that of its rea- gents blank (AA=48nm),so that a deep background is caused at them.of the coordination compound,which is not desirable.To overcome it,a dual- wavelength mcthod is applieds,.If an instrumenl of dual-wavelength is used,the absorbance of the coloured coordination compound,4:and 42,are measured at 578nm and 530nm respectively against its reagents blank as refer- 389

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ence and A4=A,-4:.If an instrument of mono-wavelength is used;at first, the absorbance of the coordination compound with excess reagents (41)is Table 1 Determination value of 3.Oug of galliur in 25,00ml of coloured solution in the presence of foreign ions mono-wavclength method dual-wavelength method Amount added Forcign ion Hg detd,value ug error.ug detd.valuc ug error ug Ba(I) 200 3.0 0 3.0 0 Mg(I) 200 3.1 +0,1 3.2 +0.2 Ni (I) 100 3.0 0 3.2 +0,2 Si ( 50 3.0 0 3.0 0 Ma(I) 20 2.9 -0.1 3.0 0 Pb(I) 20 2.9 -0.1 2.9 -0.1 Sn(I) % 3.0 0. 3.0 0 Zn(I) 20 3.1 +0.1 3.1 +0.1 Co(I) 4 3.0 0 3.0 0 cd(I) 5 3.0 0 3.0 0 A1(I) 5.5 +2.5 5.8 +2.8 Bi(I) 1 3.0 0 3.0 0 Cu(I) 1 3.7 +0.7 3.3 +0.8 Fe(I) √ 3.1 +0,1 3.2 +0.2 Ge(N) 3.9 +0.9 3.9 +0.9 In (I) 1 3.9 +0.9 3,8 +0.8 Mo(VI) 1 3.5 +0.5 3.8 +0.8 Ti (N) 1 3.1 +0.1 3.1 +0.1 W() 1 3.4 +0.4 3.6 +0.6 Zr (N) 3.2 +0,2 3.1 +0.1 note the max tolerable amount has not tested, 1.0 N 0.8 Fig.3 Calibration cutve curve 1.mono-wavelength 0.6 method curve 2.dual-wavelength method 0.4 .. 0.2 0.040.120.200.28 Concentration of Ga/ug.m1-1 390

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measured at 578nm against its reagents blank as reference;then the absorbance of reagents (A2)is measured at 530nm against the coordination compound (with excess reagents)as reference;and A4=4+42.The measured values of aA with these two types of instrument should be same.The calibration curve drawn by the dual-wavelength method shows a higher molar absorptivity (2.33x 1051.mol-i.cm-1)than that drawn by the mono-wavelength method. Besides,its linear range (0~7,0ug/25ml)is wider and its reproducibility is also better than that of mono-wavelength method (Fig.3). 3.3 Spectrophotometric Determination of Microamount of Gallium in the Copper Minerals Weigh accurately 0.5000~1.0000g sample,fuse it with 4~5g of sodium hydroxide in a silver crucible for 20min.Cool and then the fused mixture is leaching with almost 50ml of boiling water.Add 20ml of concentrate hydro- chloric acid and evaporate the mixture to dryness for the dehyhration of silicic acid;then dissolve the formed salts with few ml of 1:1 hydrochloric acid by carefully heating,subsequently dilute it to 50.00ml.An aliquot of 2~10ml (if it is less than 10ml,add 1:1 hydrochloric acid to 10ml)is treated with 15%titanium trichloride (dropped to the disappearence of purple colour),and place it aside for 30min;then it is extracted with 10ml of butyl acetate. Remove the raffinate and scrub the organic phase twice with 1:1 hydrochloric acid (at the first scrubbing,2 drops of titanium trichloride solution is added); then the gallium is stripped from the organic phase to the aqueous phase with 10ml of water for 1min.Remove the organic phase and dilute the aqueous phase to 25.00ml with water.An aliquot of this aqueous solution may be used to determine gallium according to the procedure described above. For the drawing of calibration curve,each aliquot of Ga(I)working solution should be diluted to 10ml with 1:1 hydrochloric acid,and then extra- ct,scrub and strip as the same treatment for the sample.The representative Table 2 Results for the determination of gallium in copper minerals(%) Determination by proposed method Sample Certified valuc mono-wavelength method dual-wavelength method detd,value variable coef. detd,value (#=6) (n=6) variable coef. Cu-1 0.00170 0,00174 3.1 0.00175 2.6 Cu-2 0.00135 0.00138 3.0 0.00138 2.4 .from north area of Hubei,China 391

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data for the determination of microamount of gallium in the copper minerals are shown in Table 2. References 1 Ci Yunxiang,Yang Ruoming.Scieatia Sinica (B edition),1985,(3):309 (in Chinese) 2 Yao Fenji,et al.Analytical Laboratory,1984,3(5):22 (in Chinese) 3 Chen Huaxu,Zhu Lin,Wang Yuxing.Rare Metals,1990,9(3):213 (in English) 4 Guo Caiwen,et al.Analytical Laboratory,1984,3(6):17 (in Chinese) 5 Wang Jixiang,et al.Fenxi Huaxue,1985,3(8):593 (in Chinese) 6 Pan Qinghong,et al.Huaxue Shiji,1985,7(6):321 (in Chinese) 7 Li Huaming,et al.Physical Testing and Chemical Analysis (Chem.Ed.), 1980,16(3):43(in Chinese) 8 Shibata S,et al.Bunseki Kagaku,1974,23:1545 (in Japanese) 9 Yang Quanshen,et al.Fenxi Huaxue,1982,10(3):167 (in Chinese) 节块式金刚石圆锯片 节块式金刚石圆锯片主要用于切割各种大理石、花岗石、耐火材料、陶瓷及其他非金属 硬脆材料。 近年来,我国石材加工业得到迅速的发展,大型石材切割锯机(中1600mm一中3000mm) 的引进、应用及国产大型锯机(φ1600mm一中2200mm)的投产,对金刚石圆锯片的需求量 大大增加,对锯片的切削质量和使用寿命要求越来越高。目前国内金刚石圆锯片生产厂家的 产品数量、质量、品种远远满足不了用户要求。为尽快达到国外同类产品的先进水平,河南 省新乡市第三轻工业机械厂与北京科技大学合作,于1988年起共同开发节块式金刚石圆锯片 产品。针对不同的石材、耐火材料等加工对象,使用不同的结合剂和配方,以及相应的工艺。 经过一年多时间的努力,已完成了设备配置及产品试制工作,并经过现场使用表明已具备了 批量生产不同规格的节块式金刚石圆锯片系列产品的能力。 现有产品规格,外径为中250一中700mm、900mm、φ1000mm、中1200mm、 中1600mm、1800mm。 新研制的产品具有加工效率高、使用寿命长、成材质量好、成本低、能耗少等特点。试 验表明,采用新型金刚石圆锯片切割石材与传统的砂锯相比,可提高出材率15%,效率提高8 倍,电耗降低50%,成本降低大约50%一70%。 392

。 , 。 , , , 了, , , , , , , · , , , 一 , , , · , , , · 少 · · , , , , , 续 , 一 , 节块式金刚石 圆锯片 节块式金 刚石圆 锯片主要用 于切割 各种大理石 、 花 岗石 、 耐火材料 、 陶瓷及其他非金属 硬脆材料 。 近年来 , 我 国石材加工业得到迅速 的发展 , 大型石材切 割锯机 中 。 。 一帕 的 引 进 、 应 用及 国产大型 锯机 拟 一中 的 投产 , 对金 刚石 圆锯片 的需 求量 大大增加 , 对 锯片的切 削质量和 使 用寿命要求越来越高 。 目前 国内金 刚石 圆锯片生 产厂家 的 产品数量 、 质 量 、 品 种远远 满足 不了 用户 要求 。 为尽快达 到 国外 同类产品 的先 进水 平 , 河南 省新 乡市第三轻工业机械厂 与北京科技大学合作 , 于 年 起共同开 发节块式金 刚石 圆锯片 产品 。 针对不 同的石材 、 耐火材料等加工对象 , 使 用不 同的结合剂和 配 方 , 以及相应的工艺 。 经过一年多时 间的努力 , 已完成了设备配置及产品试制工作 , 并经过现场使 用表明 已 具备了 批量生 产不同规格 的节块式金 刚石 圆 锯片 系列产品 的能力 。 现 有 产 品 规 格 , 外 径 为 中 一中 、 中 、 中 、 中 、 中 、 伞 。 新研制的 产品 具有加 工效率高 、 使用寿命长 、 成材质量 好 、 成本低 、 能耗少等特点 。 试 验表明 , 采用 新型金 刚石 圆 锯片切割石材与传统的砂 锯相 比 , 可提高 出材率 , 效率提高 倍 , 电耗降低 , 成本降低大约 一

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