[Header] Format=SMU ver=3 appl=GUMWB32 MR=0 FUEB=0 [Title] Title='Determination of Cadmium Release from Ceramic Ware by Atomic Absorption Spectrometry' Description=12 Description[0]='This is the example A5 of the EURACHEM / CITAC Guide "Quantifying Uncertainty' Description[1]='in Analytical Measurement", Second Edition.' Description[2]='' Description[3]='The amount of released cadmium from ceramic ware is determined using atomic' Description[4]='absorption spectrometry. The procedure employed is the empirical method BS' Description[5]='6748.' Description[6]='' Description[7]='The item to be tested is filled with a 4 % v/v acetid acid solution for a given' Description[8]='lenght of time, the amount of cadmium released from the item is then calculated' Description[9]='from the measured cadmium concentration in the leach solution and the volume of' Description[10]='the leach solution. Parameters such as leaching time, temperature, acid' Description[11]='concentration etc. are specified in the empirical method.' [Model] Model=11 Model[0]='{calculation of the uncertainty of volume V_L}' Model[1]='' Model[2]='V_L = V_L\sp\nominal * f_VL\minus\filling * f_VL\minus\temperature * f_VL\minus\reading * f_VL\minus\calibration;' Model[3]='' Model[4]='{calculation of the uncertainty of the surfache area}' Model[5]='' Model[6]='a_V = a_V\sp\nominal * f_aV\minus\length1 *f_aV\minus\lenght2 * f_aV\minus\area;' Model[7]='' Model[8]='{calculation of the mass of cadmium leached}' Model[9]='' Model[10]='r = c_0 * V_L / a_V * d * f_acid * f_time * f_temperature;' [Components] CompOrder=3 Comp=17 Comp[0]=V_L_ Comp[1]=V_L\sp\nominal_ Comp[2]=f_VL\minus\filling_ Comp[3]=f_VL\minus\temperature_ Comp[4]=f_VL\minus\reading_ Comp[5]=f_VL\minus\calibration_ Comp[6]=a_V_ Comp[7]=a_V\sp\nominal_ Comp[8]=f_aV\minus\length1_ Comp[9]=f_aV\minus\lenght2_ Comp[10]=f_aV\minus\area_ Comp[11]=r Comp[12]=c_0_ Comp[13]=d Comp[14]=f_acid_ Comp[15]=f_time_ Comp[16]=f_temperature_ [COMP 0] Type=Temp Definition='Volume of the leachate' Unit='L' Description=0 Fcov=2 NomUnit= UncUnit= CovID=1 UncID=0 Vnom=0.33034 Ustd=0.00182090668528546 Neff=10000 HB=0 HC=0 HR=0 IO=0 [COMP 1] Type=Const Definition='Nominal volume of the leachate' Unit='L' Description=5 Description[0]='The nominal volume is not associated with any uncertainties. Four different' Description[1]='factors contribute to the uncertainty of the real volume, filling, temperature,' Description[2]='reading and calibration. These are introduced in the uncertainy budget through' Description[3]='the factors f_VL\minus\filling, f_VL\minus\temperature, f_VL\minus\reading and' Description[4]='f_VL\minus\calibration.' Vnom=0,332 [COMP 2] Type=TypBTriangl Definition='Uncertainty contribution of V_L due to filling of the vessel' Unit='' Description=3 Description[0]='The method requires the vessel to be filled ''to within 1mm from the brim''. For' Description[1]='a typical drinking or kitchen utensil, this represents about 1% of the total' Description[2]='height. The vessel will therefore be 99.5% ± 0.5% filled.' Vnom=0.995 Hlim=0.005 [COMP 3] Type=TypBRectang Definition='Uncertainty contribution of V_L due to temperature variation' Unit='' Description=10 Description[0]='The temperature of the acetic acid has to be 22 ±2°C, according to the method.' Description[1]='This range leads to an uncertainty in the measured volume, due to a' Description[2]='considerably larger volume expansion of the liquid compared to the vessel. The' Description[3]='coefficient of volume expansion for water is 2.1\cdot\10^-4^°C^-1^. This leads' Description[4]='to a possible volume variation of ±(332 \cdot\ 2 \cdot\ 2.1\cdot\10^-4^) mL. A' Description[5]='rectangular distribution is assumed for the temperature variation of the' Description[6]='volume. Since f_VL\minus\temperature is a multiplicative factor to the nominal' Description[7]='volume, which is only used to introduce the temperature uncertainty, it has the' Description[8]='value 1. Its uncertainty is calculated as the possible volume variation divided' Description[9]='by the volume.' Vnom=1 Hlim==2.1e-4*2 [COMP 4] Type=TypBTriangl Definition='Uncertainty contribution of V_L due to reading of the measuring cylinder' Unit='' Description=0 Vnom=1 Hlim=0.01 [COMP 5] Type=TypBTriangl Definition='Uncertainty contribution of V_L due to calibration of the measuring cylinder' Unit='' Description=8 Description[0]='The volume is calibrated within ±2.5 mL for a 500 mL measuring cylinder. No' Description[1]='further statement is made about the level of confidence or the underlying' Description[2]='distribution. An assumption is necessary to work with this uncertainty' Description[3]='statement. In this case a triangular distribution is assumed. Since' Description[4]='f_VL\minus\calibration is a multiplicative factor to the nominal volume, which' Description[5]='is only used to introduce the calibration uncertainty, it has the value 1. The' Description[6]='halfwidth of limits corresponds to the relative uncertainty as stated by the' Description[7]='manufacturer (i.e. 2.5 mL / 332 mL).' Vnom=1 Hlim==2.5/332 [COMP 6] Type=Temp Definition='Surface area of the vessel' Unit='dm^2' Description=0 Fcov=2 NomUnit= UncUnit= CovID=1 UncID=0 Vnom=2.37 Ustd=0.0642752209228003 Neff=63 HB=0 HC=0 HR=0 IO=0 [COMP 7] Type=Const Definition='Nominal surface area of the vessel' Unit='dm^2' Description=4 Description[0]='The nominal surface are is not associated with any uncertainties. Three' Description[1]='different factors contribute to the uncertainty of the real surface area, that' Description[2]='are the two length measurements required to calculate the surface area, and an' Description[3]='area-factor, covering the imperfect geometry of any real vessel.' Vnom=2.37 [COMP 8] Type=TypBNormal Definition='Uncertainty contribution to a_V of first length measurement (i.e. height)' Unit='' Description=5 Description[0]='Typically, two length measurements are required to calculate the surface area' Description[1]='of a vessel. In this case, the item was approximated by a cylindrical geometry.' Description[2]='Typical dimensions are between 1.0 and 2.0 dm, leading to an estimated' Description[3]='uncertainty of 1 mm. The two length measurements required for this vessel were' Description[4]='1.45 and 1.64 dm.' Vnom=1 Uexp==0.01/1.45 Fcov=1 [COMP 9] Type=TypBNormal Definition='Uncertainty contribution to a_V of second length measurement (i.e. lenght)' Unit='' Description=5 Description[0]='Typically, two length measurements are required to calculate the surface area' Description[1]='of a vessel. In this case, the item was approximated by a cylindrical geometry.' Description[2]='Typical dimensions are between 1.0 and 2.0 dm, leading to an estimated' Description[3]='uncertainty of 1 mm. The two length measurements required for this vessel were' Description[4]='1.45 and 1.64 dm.' Vnom=1 Uexp==0.01/1.64 Fcov=1 [COMP 10] Type=TypBNormal Definition='Uncertainty contribution to a_V due to imperfect geometry' Unit='' Description=4 Description[0]='The item is not a perfect geometric shape (cylinder in this case). Therefore' Description[1]='the real surface area may deviate from the caluclated one. This deviation was' Description[2]='estimated to be 5% at 95% confidence level. To obtain the standard uncertainty' Description[3]='the possible deviation is divided by 1.96.' Vnom=1 Uexp==0.05/1.96 Fcov=1 [COMP 11] Type=Result Definition='Mass of cadmium leached per unit area' Unit='mg/dm^2' Description=0 Fcov=2 NomUnit= UncUnit= CovID=1 UncID=0 Vnom=0.0362398312236287 Ustd=0.00341777839010857 Neff=169 HB=1 HC=0 HR=1 IO=0 [COMP 12] Type=TypBNormal Definition='Content of cadmium in the extraction solution' Unit='mg/L' Description=8 Description[0]='The content of cadmium in the extraction solution is calculated using a' Description[1]='calibration curve. For the calibration curve five calibration standards were' Description[2]='prepared and measured 3 times each. Using a linear least square fit, the slope' Description[3]='and intercept of the calibration curve have been calculated. Using this data,' Description[4]='the concentration c_0 was calculated from a duplicate measurement of the actual' Description[5]='leach solution. The calculation of the uncertianty of the least square fit is' Description[6]='described in Appendix E3 of the EURACHEM / CITAC Guide. Only the final result' Description[7]='of this calculation is used here.' Vnom=0.26 Uexp=0.018 Fcov=1 [COMP 13] Type=TypBNormal Definition='Dilution factor (if used)' Unit='' Description=2 Description[0]='For this sample, no dilution of the leach solution was necessary, therefore no' Description[1]='uncertainty needs to be introduced here.' Vnom=1 Uexp=0 Fcov=1 [COMP 14] Type=TypBNormal Definition='Influence of the acid concentration' Unit='' Description=11 Description[0]='Data from two study on the effect of acid concentration on lead release was' Description[1]='used to estimate this factor. One study showed that lead release was increased' Description[2]='by approximately 0.1 when the acid concentration was increased from 4 to 5%' Description[3]='v/v. Another study reported a 50% increase of the lead release for a change of' Description[4]='acid concentration from 2 to 6% v/v. Assuming a liner effect, on can estimate a' Description[5]='change of f_acid of 0.1 per 1% v/v change of acid concentration. In another' Description[6]='experiment the concentration of the acetic acid and its standard uncertainty' Description[7]='have been established using titration with standardised NaOH solution,' Description[8]='resulting in an acetic acid concentration of 3.996 % v/v with a standard' Description[9]='uncertainty of 0.008% v/v. The uncertainty of f_acid can then be calculated as' Description[10]='0.008 \cdot\ 0.1.' Vnom=1 Uexp==0.008*0.1 Fcov=1 [COMP 15] Type=TypBRectang Definition='Influence of the duration' Unit='' Description=7 Description[0]='For a relatively slow process such as leaching, the amount leached will be' Description[1]='approximately proportional to the leaching time for small changes in that time.' Description[2]='In a study, a mean change of concentration over the last six hours of leaching' Description[3]='of approximately 1.8 mg \cdot\ L^-1 (=0.3% / h) was found. The leaching time is' Description[4]='specified in the method as 24 ±0.5 h, the content of Cd in the extraction' Description[5]='solution therefore needs to be corrected by a factor of 1 ±(0.5 \cdot\ 0.003).' Description[6]='A rectangular distribution is assumed for this factor.' Vnom=1 Hlim==0.5*0.003 [COMP 16] Type=TypBRectang Definition='Influence of the temperature' Unit='' Description=9 Description[0]='A number if studies on the effect of temperature on metal release from ceramic' Description[1]='ware have been undertaken. The temperature effect is substantial, and a' Description[2]='near-exponential increase in metal release with temperature is observed until' Description[3]='limiting values are reached. Nevertheless, only one study gives information for' Description[4]='the temperature range 20-25°C. The metal release approximately linear wit' Description[5]='temperature in this temperature range, with a gradient of approximately 5%' Description[6]='°C^-1^. For the ±2°C range allowed by the empirical method, this leads to a' Description[7]='factor f_temperature of 1 ± 0.1. A rectangular distribution is assumed for this' Description[8]='factor.' Vnom=1 Hlim=0.1 [Correlations] Description=0