氢氧化锶溶液中金属元素检测方案(ICP-AES)

ICP ATOMIC EMISSION SPECTROSCOPY Analysis of metals in 200 g/l Strontium Hydroxide Nathalie Le CorreHORIBA Scientific Longjumeau， France Keywords： chemicals， inorganic A sample with 200 g/L strontium hydroxide waspresented to this laboratory for trace determina-tion. There was only one sample to be analyzedand， as it had a complex matrix， the standardaddition method was used for analysis. 2 Principle 2.1 Technique used The elemental analysis of a 200 g/L strontiumhydroxide solutionwas undertakenbyInductively Coupled Plasma Optical AtomicSpectrometry (ICP-AES).The sample is nebu-lized then transferred to an argon plasma. It isdecomposed， atomized and ionized wherebythe atoms and ions are excited.We measure theintensity of the light emitted when the atoms orions return to lower levels of energy. Each ele-ment emits light at characteristic wavelengthsand these lines can be used for quantitativeanalysis after a calibration. 2.2 Wavelength choice The choice of the wavelength in a given matrixcan be made using the "profile" function， or byusing Win-IMAGE， which is rapid semi-quantita-tive analysis mode using multiple wavelengths.The principle is the same in either case： recordthe scans of analytes at low concentration， andof the matrix. By superimposing the spectra，wesee possible interferences. 2.3 Limits of detection estimation The limits of detection are calculated using thefollowing formula： LOD = k x BEC x RSDo With： LOD= limits of detection， k= 3 for the normal 3-sigma values， BEC= Background equivalent concentration， RSDo= relative standard deviation of the blank. To calculate the LOD， a calibration curve is con-structed using two points， 0 ppm and 5 ppm， orsome concentration where the calibration is lin-ear； this gives the BEC. The RSDo is evaluatedby running the blank ten times. 3 Sample preparation 20.006 g of sample was weighed and dissolvedwith 15 ml 69 % HNO3 and diluted up to 100 mlwith deionized water. The high volume of nitricacid was to avoid precipitation. Two spiked samples were prepared for the stan-dard addition. Addition 1： 0.1 mL of standard"A"0.2 mL ofsolution"B" with 25 mL of Sr(OH)2.8H2O.Addition 2： 0.2 mL of standard"A"with 25 mL ofSr(OH)2.8H20. With standard "A" containing ： 1 g/L of Na， Ca， Ba， 0.25 g/L of S. and standard "B" containing 25 mg/L of Cd， Cr，Cu， Fe， Mn， Ni， Pb， Zn. The concentrations of the spiked samples arelisted in Table 1. Table 1： Standard Addition concentration Element Concentration of Wavelength Unknown Addition1 Addition2 sample Ba 233.527 X X+ 4 X+8 Ca 223.061 X+4 X+8 Cd 317.933 X+ 0.2 Cr 228.802 X+0.2 Cu 324.754 X X +0.2 Fe 259.940 X X+0.2 Mg 279.553 X X+ 0.2 Mn 257.610 X X+0.2 Na 289.592 X X+4 X+8 Ni 231.604 X+0.2 Pb 220.353 X+0.2 S 181.978 X X+1 X+2 Zn 213.856 X+0.2 4. Instrument specification The work was done on a ULTIMA.The specifica-tions of this instrument are listed Table 2 and 3. Table 2： Specification of spectrometer Parameters Specifications Mounting_ Czerny Turner Focal length 1m Nitrogen purge Yes Variable resolution Yes Grating number of grooves 2400 gr/mm Order 2nd order Table 3： Specification of RF Generator Parameters Specifications Type of generator Solid state Observation Radial Frequency 40.68 MHz Control of gas flowrate by computer Control of pump flow by computer Cooling air 5 0perating conditions The operating conditions are listed in Table 4below. Table 4： Operating conditions Parameter Condition RF Generator power 1200 W Plasma gas flowrate 12 L/min Auxiliary gas flowrate 0 L/min Sheath gas flowrate 0.2 L/min Nebulizer gas flowrate 0.8 L/min Nebulizer flowrate 3 bars (45 psi) Sample uptake 1 mL/min Type of nebulizer Parallel Type of spray chamber Cyclonic Argon humidifier No Injector tube diameter 3.0 mm 6 Wavelength selection and analyti-cal conditions For each element， the line with the highest sensi-tivity was used for analysis， because there were noproblems with interferences. The analysis condi-tions were the same for all elements except thealkali elements. Table 5： Analytical conditions Element Slits Analysis Integration (um) mode time (sec) All elements 20x15 Direct peaking 8 Na 20x80 Gaussian 0.5 The use of the parallel nebulizer and the largeinternal diameter (ID) of the injector tube enabledtrouble free analysis， even with the high dissolvedsalts. The larger the ID injector tube also ensures aminimization of the interferences. Due to the highdissolved salts， an initial conditioning of the spraychamber is advised for maximum stability. It isalso imperative to use matched standards or stan-dard addition because of the viscosity of solutionswith high dissolved solids. 7 Discussion 7.1 Limits of Detection The limits of detection were calculated using theformula in paragraph 2.3. They were calculated inug/kg in the solid sample. Table 6： Limits of Detection Elements Wavelength LOD (ug/kg) (nm) Ba 233.527 9.3 Ca 223.061 19 Cd 317.933 82 Cr 228.802 23 Cu 324.754 100 Fe 259.940 38 Mg 279.553 3 Mn 257.610 5 Na 289.592 78 Ni 231.604 59 Pb 220.353 88 S 181.978 201 Zn 213.856 11 7.2 Determination of the unknown sample Using the two spiked samples and the unknown， acalibration curve was constructed. The concentra-tions of the traces in the unknown are given by theintercept of their calibration curves. The resultsfor unknown are given in Table 7. Table 7： Results Element Concentration Concentration in mg/kg Expected in mg/l in mg/kg Ba 233.527 2.5 12.5 <30 Ca 223.061 5.4 27 <400 Cd 317.933 0.005 0.025 Cr 228.802 0.013 0.065 Cu 324.754 0.1 0.5 Fe 259.940 0.14 0.7 <10 Mg_ 279.553 1.52 7.6 Mn 257.610 0.009 0.045 Na 289.592 2.53 12.65 <100 Ni 231.604 0.015 0.075 Pb 220.353 0.032 0.16 S 181.978 1.9 9.55 Zn 213.856 0.036 0.18 To achieve the lowest detection limits， dilution isundesirable..Theeresults showthe HORIBAScientific spectrometers are able to perform anexcellent analysis， even with high dissolved solids.This enables the analysis to be performed to thebest detection limits possible. Scientific France： HORIBA Jobin Yvon S.A.S.， 16-18 rue du Canal，91165 Longjumeau Cedex - Tel：+33 (0)16454 13 00- Fax： +33 (0)1 69 09 07 21-Email： info-sci.fr@horiba.com USA： HORIBA Jobin Yvon Inc.， 3880 Park Avenue， Edison， NJ 08820-3012. Toll-free：+1-866-jobinyvon- Tel： +1-732-494-8660-Fax：+1-732-549-5125 Email： info-sci.us@horiba.com Japan： HORIBA Ltd.， Scientific Instruments Sales Dept.， Alte-Building Higashi-Kanda， 1-7-8 Higashi-Kanda， Chiyoda-ku， 101-0031 Tokyo - Tel： +81 (0)3 3861 8231 Fax： +81 (0)3 3861 8259-Email： info-sci.jp@horiba.com Germany： HORIBA Jobin Yvon GmbH， Hauptstrasse 1， 82008 Unterhaching - Tel：+49 (0)89 46 23 17-0- Fax： +49 (0)89 46 23 17-99-Email： info-sci.de@horiba.com Italy： HORIBA Jobin Yvon Srl， Via Cesare Pavese 35/AB， 20090 Opera (Milano) - Tel： +39 0 2 57 60 30 50-Fax：+39 0257 60 08 76-Email： info-sci.it@horiba.com UK： HORIBA Jobin Yvon Ltd， 2 Dalston Gardens， Stanmore， Middlesex HA7 1BQ - Tel： +44 (0)208204 8142-Fax： +44 (0)20 8204 6142-Email： info-sci.uk@horiba.com China： HORIBA Jobin Yvon SAS， Room 1801， Capital Tower No.6， Jianguomenwai Av.， Chaoyang District， Beijing 100022- Tel： +86 (0)10 8567 9966-Fax： +86 (0)10 8567 9066 Email： info-sci.cn@horiba.com Other Countries： Tel： +33 (0)1 64 54 13 00-Email： info.sci@horiba.com ORIBAScientific HORIBAExplore the futureAutomotive Test SystemsslProcess & Environmental MedicalSemiconductor I Scientific To achieve the lowest detection limits, dilution is undesirable. The results show the HORIBA Scientific spectrometers are able to perform an excellent analysis, even with high dissolved solids. This enables the analysis to be performed to the best detection limits possible.