اندازه گيري هم زمان نيترات و نيتريت در آب آشاميدني و سيب زميني به كمك دستگاه طيف سنج تحرك يوني با منبع يونيزاسيون الكترواسپري

چكيده انگليسي :

Simultaneous Determination of Nitrate and Nitrite in Drinking Water and Potato Using Electrospray Ionization Ion Mobility Spectrometry ESI IMS Firoozeh torki March 13 2011 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Lanquage FarsiSupervisers Assis Prof Mohammad Taghi Jafari jafari@cc iut ac irAssoc Prof Mohammad Saraji saraji@cc iut ac irAbstract Nitrate and nitrite play an important role in the nitrogen cycle involving the complexinteraction of different ecosystems of the biosphere Both nitrate and nitrite are present in water andfood and that humans are exposed to these ions by these sources The nitrate in drinking watercomes from a variety of sources many of which are dependent to some extent on human activityand so vary between regions and with time Nitrate and nitrite are usually added to processed meatproducts to provide protection against microorganisms that cause food poisoning Nitrite may reactwith secondary amines to form nitrosoamines a class of carcinogens Nitrate although it is morestable than nitrite can act as a reservoir for nitrite Thus both nitrate and nitrite need to bemonitored to ensure the quality and safety of meat products In this research the negative electrospray ionization ion mobility spectrometry ESI IMS has been evaluated for simultaneous determination of nitrate and nitrite The methodology reportedhere is very simple and rapid in addition to inexpensiveness for analysis of NO3 and NO2 withoutany complicated preparation methods The ESI IMS instrument is inexpensive fast accurate andsensitive When compared to methods currently used for nitrate and nitrite analysis ESI IMSmethod has an analysis time shorter them traditional methods In this methods the analyte isintroduced as a liquid and it is then ionized by Electrospray Ionization sources Standard solutionsof nitrate nitrite chloride formate and acetate were analyzed using ESI IMS and distinct peakpatterns and reduced mobility constants K0 were observed for respective anions The IMSresponse of trinitrotoluene TNT using as standard peak that appears at right site of peaks solvent The identities of the nitrate and nitrite mobility peaks were verified by comparison of reducedmobility constants with that of identified nitrate and nitrite ions reported in literature In the analysis of binary mixture no overlapping has been observed between nitrate andnitrite ion peaks A working range of 3 orders of magnitude were observed A working range ofnitrate and nitrite 5 1000 and 10 1000 g L 1 were obtained A linear dynamic range of 2 orders ofmagnitude of nitrate and nitrite 10 1000 g L 1 and quantitative detection limits of 10 g L 1 fornitrate and nitrite were obtained The limits of detection of 4 7 and 3 8 g L 1 for nitrate and nitritewere obtained The calibration plots were linear in the range of 10 to 700 g L 1 for nitrate andnitrite The calibration curves showed R2 value of 0 9910 and slope of 2 70 for nitrate and R2 valueof 0 9925 and slope of 2 89 for nitrite The relative standard deviations were under 5 Recoverieswere obtained for nitrate and nitrite as higher than 70 However the nitrite amount lower than thelimit of detection was found for two different real samples The validity of the ESI IMS methodwas demonstrated by the analysis nitrate and nitrite in drinking water and potato as real samples Keywords Simultaneous Analysis Nitrate Nitrite Electrospray Ionization Ion MobilitySpectrometry

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اندازه گيري هم زمان نيترات و نيتريت در آب آشاميدني و سيب زميني به كمك دستگاه طيف سنج تحرك يوني با منبع يونيزاسيون الكترواسپري