环境水中（类）金属及其化合物检测方案

ICP OPTICAL EMISSION SPECTROSCOPYAPPLICATION NOTE 40 Detection Limits in Water Using Assorted Sample IntroductionSystems Agnes Cosnier， Geoff Tyler， Lisa Goldstone* Jobin Yvon SAS， 16-18， rue du Canal， 91165 Longjumeau， Cedex， France *Jobin Yvon， Inc.， 3880 Park Avenue， Edison， NJ 08820 Keywords： detection limit， performance， nebulizer， sample introduction， hydride generation，ultrasonic 1 Introduction A variety of sample introduction systems exist toachieve improvements in detection limits. Thestandard system used for Jobin Yvon ICP spec-trometers is typically the concentric pneumaticnebulizer combined with a cyclonic spray cham-ber. This system is referred to as pneumatic neb-ulization and provides the results shown in Table4 (pneumatic nebulization). The Ultrasonic Neublization system， shown inFigure 1 to the right， offers improved sensitivitydue to the high efficiency of small droplet pro-duction using a transducer and desolvation sys-tem. An improvement of 5 to 20 times can beseen in detection limits， depending on the ele-ment and the matrix. In addition， the quantity ofaerosol injected into the plasma is very high withup to 30% compared to less than 2% with othernebulizers. For difficult organic solutions such asnaptha and gasoline where extra desolvation isnecessary， a membrane desolvator is available. To improve detection limits for elements such asHg， As， Sb， Se Bi， Ge， Te and Sn， one can usehydride generation. This is particularly useful forenvironmental analysis， where the concentrationranges are close to the ug/L level. One of the maindrawbacks of this technique， until recently， hasbeen the requirement of performing the analysistwice： once for the normal elements and the otherfor the hydride species. Additionally， it was nec-essary to replace the standard spray chamber sys-tem with a hydride generator device. With theunique Concomitant Metals Analyzer (CMA) fromJobin Yvon shown in Figure 2 to the right， it ispossible to run one analysis with detection limitsimproved for the hydrides by a factor of 5 to 50times with little difference in detection limits forthe other normal elements.. See Application Note13： Comparison of Classical Hydride Generator and Concomitant Metals Analyzer for a detailed Figure 1： Diagram of an ultrasonic nebulizer(Courtesy of Cetac Technologies，Omaha，Nebraska， USA) Figure 2： Concomitant Metals Analyzer (CMA) comparison of standard hydride generation withthe CMA system. The work presented in this note was done on a JYULTIMA 2 configured with the appropriate sampleintroduction system. The specifications of thisinstrument are listed in Table 1 and 2. Table 1： Specification of spectrometer Parameter Condition Mounting Czerny Turner Focal length 1 m Optic thermoregulation Yes Nitrogen purge Yes Grating number of grooves 2400 gr/mm 1st order resolution 0.010 nm 2nd order resolution 0.005 nm Order andorder(120-330 nm) Table 2： Specification of RF Generator Parameter Condition Type of generator Solid state Observation Radial view Frequency 40.68 MHz Control of gas flowrate By computer Control of pump flow By computer Cooling Air 3 Operating conditions The operating conditions are listed in Table 3 below. Table 3： Operating conditions Parameter Condition RF Generator power 1000 W Plasma gas flowrate 12 L/min Auxiliary gas flowrate 0 L/min Sheath gas flowrate 0.1 L/min Nebulizer gas flowrate 1 L/min Nebulizer flowrate 3.4 bars (51 psi) Sample uptake 1 mL/min Type of nebulizer Glass concentric Type of spray chamber Glass cyclonic Argon humidifier Yes Injector tube diameter 3.0 mm 4 Detection Limits The limits of detection at 3 sigma are calculatedusing the following formula： With： LOD = limit of detection， BEC = background equivalent concentration， RSDB = relative standard deviation of the blank on10 replicates. 5 Results Detection limit results obtained are shown in Table4. Elements shown were analyzed at the sametime in one run under identical conditions asshown in Tables 1，2 and 3. Element Pneumatic Ultrasonic Hydride US EPA US EPA EN ISO Nebulization Nebulization(CMA) Method Method 11885：1996 200.7 200.8 (LOD-wavelength in nm) Sb 1.5 0.15 0.2 32 0.4 100-206/217 Sc 0.09 Se 1.5 0.2 0.2 75 7.9 100-196/203 Si 1.5 26 (SiO2) 20-251/212 30-288 Sn 1.3 0.2 25 100-235/189 Sr 0.03 0.77 0.5-407 10-421 100-460 Ti 0.15 0.03 3.8 5-334 10-336/337/368 TI 1.0 0.2 40 0.3 V 0.20 0.05 7.5 2.5 10-290/292 10-310/311 W 2.0 30-207 60-209/239 60-222/202 Y 0.20 Zn 0.15 0.025 1.8 1.8 10-206 5-213 Zr 0.30 10-343 50-354 The race for lower detection limits is continuous.The ICP spectrometer system offered by JY config-ures a rugged， flexible sample introduction systemwith a high-resolution spectrometer to provide traceand ultra-trace detection limits on a routine basis. This capability of providing trace detection limitswith a radial view plasma and the standard sampleintroduction system is enhanced to the ultra-trace level with the addition of either the ultrasonic nebu-lization system or a hydride generation system.This performance is made possible by the combina-tion of several factors including a robust plasma，radial plasma viewing， large injector bore， and theunique sheath gas system. For more details on thefeatures of JY ICP spectrometers， read TechnicalNote 7： Unique Features of Jobin Yvon ICP spec-trometers. In December 2001， the Official Journal of FrenchRepublique issued decree number 2001-1220(December 2Oth， 2001)， for waters for human con-sumption (natural mineral water not included)Water should respect values less or equal to limitsof quality defined as：ISb 5ppb， As10ppb， Ba0.7ppm， Cd 5ppb， Cr 50ppb， Cu 2ppm， Hg 1ppb， Ni20ppb， Pb 10ppb， and Se 10ppb. The sensitivity provided by the JY ULTIMA 2 con-figured with a variety of sample introduction sys-tems is sufficient to perform environmental analysisin compliance with the detection limits of US EPAMethod 200.7 for water and wastewater effortless-ly. Even detection limit requirements for US EPAMethod 200.8(ICP-MS) are well within reach withthe USN and/or CMA accessories. For more detailson environmental analysis please read ApplicationNote 36： Environmental Analysis using a HighThroughput ICP OES. In the USA： Jobin Yvon Inc.3880 Park AvenueEdison， NJ 08820Tel： 1-732-494-8660Fax： 1-732-494-8796E-mail： info@jobinyvon.com Jobin Yvon S.A.S. Horiba Ltd. 16-18， rue du Canal 91165 Longjumeau Cedex Tel： (33) 1/64 541300 Fax： (33) 1/69 0990 88 Germany： (49) 89/46 23 17-0 2 Miyanohigashi， KisshoinMinami-ku， Kyoto 601-8510TEL： (81) 75 313 8121FAX： (81)75 321 5725www.horiba.comChina： (86)10/6849 22 16 Italy： (39) 2/57 6056 90 Spain： (34) 91/724 16 57 U.K.：(44) 20/82 048142