اندازه گيري مقادير كم سورفكتانت هاي كاتيوني ﴿ستيل تري متيل آمونيوم برميد ﴾بر اساس تشكيل كمپلكس زوج يون با اريو كروم بلاك Tبه روش اسپكتروفتومتري و تزريق در جريان پيوسته

چكيده انگليسي :

AbstractCationic surfactants are one important type of surfactants are frequently used in cleaningagents and cosmetics and also as auxiliary agents in industrial products and in medicaltreatment Cationic surfactants are used commercially as fabric softeners and as hairrinsers The field of their application is widespread Moreover cationic surfactants have amarked antimicrobial effect Synthetic surfactants are toxic pollutants in natural water It isnecessary to determine these surfactants in water for the evaluation of water pollution fromindustrial and domestic waste waters Almost all the methods for spectrophotometricdetermination of surfactants are based on the formation of ion associates with dyes or metalcomplex and then organic solvents were used for the extraction These solvents have aharmful effect on analysts and the environment Therefore a simple method for thespectrophotometric determination of trace surfactants without solvent extraction isdesirable Various spectrophotometric methods have been reported for the determination ofcationic surfactants in aqueous solution based on the spectral change of bromothymol blue phenylazophenol dye bromocresol purple congo red and thymolphthalein rose bengal andphloxine B and erythrosine B However many of those methods have used organic solventfor the extraction of the formed ion pair in nonaqueous solvent A non extraction FIAspectrophotometric determination of cationic surfactants has been proposed based onfollowing the change in absorption spectra of anionic dyes in presence of cationic anionicand nonionic surfactants and or the dye absorption decrease The simple methods of choicefor the determination of cationic and nonionic surfactants could be methods based on theformation of ion association complex between the cationic surfactant with an anionic dye In this project The measurement of cationic surfactant especially cetyl trimethyl ammonium bromide CTAB by two different methods based on spectrophotometry andFlow injection analysis were the main aim of this project In the first method a simplespectrophotometric method was developed for the determination of CTAB The methodwas based on the formation of Eriochrom Bllock T EBT and CTAB complexes in a basicmedia The reaction was monitored photometrically by measurement of the absorbance at708 nm The influences of different variables such as pH concentration of Eriochromeblack T and ionic strength on the absorbance signal of the batch spectrophotometricmethod were studied to find the optimum conditions The results showed that pH of 9 0 and EBT concentration of 2 25 10 5 M was the best A detection limit of 3 0 M andlinear calibration curve from 30 300 M and 300 5000 M were obtained under theoptimum conditions The relative standard deviation for ten replicate measurements of20 0 60 0 and 200 0 M CTAB were 3 4 1 2 and 1 3 respectively The interferenceeffect of several inorganic and organic compounds were studied CTAB in real samplessuch as conditioner shampoo drinking water river water and pool water were determinedby this method with satisfactory results In the second part a Flow injection method wasdeveloped for the determination of cetyl trimethyl ammonium bromide based on itsinteractions with EBT as an anionic dye in basic media The reaction was monitoredphotometrically by measuring the absorbance of EBT CTA complex at 708 nm Inaddition all of the chemical and instrumental parameters affect on the sensitivity of theflow system including pH concentration of Eriochrome black T and ionic strength plus thereagents flow rates sample injection volume and length of the reaction 4 coil were studied The results showed that pH of 9 0 and EBT concentration of 1 35 10 M length of thereaction coil of 310 cm sample volume of 186 L and pump flow rate of 110 mL h werethe best Under the optimum conditions a calibration graph from 20 0 200 0 M of CTABand a detection limit of 1 0 M were obtained The relative standard deviations for fivereplicate measu

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