WAGENINGEN EVALUATING PROGRAMS FOR ANALYTICAL LABORATORIES. Certificate of Analysis. International Soil-Analytical Exchange REFERENCE MATERIAL

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1 WAGENINGEN EVALUATING PROGRAMS FOR ANALYTICAL LABORATORIES Certificate of Analysis International Soil-Analytical Exchange REFERENCE MATERIAL ISE sample 946 $Dd

2 General Information Certificate of Analysis ISE 946 In this report an overview is given of analytical data for this sample collected in our proficiency testing program. The consensus values are calculated using a robust statistical model. With this NDA model mean and standard deviation are calculated using all reported data when at least 8 results are left after removal of reported 'lower than' (<) and 0 (= zero) values. No outliers are removed. This report is divided into three sections: Consensus Values, Indicative Values and Values for Information. The division is made on the reliability of the data. Consensus Values are based on at least 16 results while the coefficient of variation is smaller than 25 %. Indicative Values are based on at least 8 and less than 16 results or a coefficient of variation between 25 % and 50 %. Other values, based on less than 8 results or a coefficient of variation higher than 50 %, are given for information only. In the section with Consensus Values the following parameters are given: mean, standard deviation, coefficient of variation, number of results, median and MAD (Median of Absolute Deviation). The confidence limits (at 95 % probabilty) are calculated for these determinands. In the section with Indicative Values the following parameters are given: mean, standard deviation, coefficient of variation, number of results, median and MAD. In the section with Information Values the following parameters are given: median, MAD and number of results. For determinands which have at least 5 results reported as smaller than (<) the median of these smaller than results is calculated. In some cases this median of < values is much smaller than median and mean of the indicative values. This may be caused by a too opmistic (too low) value for the detection limit reported by a (small) majority of participating laboratories who report < -values. Sample information WEPAL reference materials are from natural sources only. There is no spiking, mixing or other alterations of the samples. ISE samples are dried at 40 o C and milled to pass a 0.5 mm sieve. This ISE sample 946 of Salt-marsh Soil from Ellewoutsdijk / Netherlands is prepared for the WEPAL proficiency programs. The sample is used in 1 period (or round). The results on which the values in this report are based were taken from the period given in the following table. Year Period Number

3 Consensus Values ISE 946 Method: Real totals Zn mg/kg Method: Acid extractable (So-called totals) Al g/kg As mg/kg B mg/kg Ba mg/kg Ca g/kg Cd mg/kg Co mg/kg Cr mg/kg Cu mg/kg Fe g/kg Hg µg/kg K mg/kg Mg mg/kg Mn mg/kg N g/kg Na mg/kg Ni mg/kg P mg/kg Pb mg/kg S mg/kg Sr mg/kg V mg/kg Zn mg/kg Method: Extraction with boiling 2M HNO3 Cd mg/kg Co mg/kg Cr mg/kg Cu mg/kg Hg µg/kg Ni mg/kg Pb mg/kg

4 Consensus Values ISE 946 Method: Extraction with boiling 2M HNO3 (cont.) Zn mg/kg Method: Extraction with 0.1M NaNO3 Cu µg/kg Method: Extraction with 0.01M CaCl2 1:10 K mg/kg Mg mg/kg N - NH4 (as N) mg/kg N - NO3 (as N) mg/kg Method: Soil characteristics EC-SC (ISO 11265) ms/m Fraction < 2 µm % Org.matter (L.O.I.) % ph - CaCl ph - H2O ph - KCl TIC=Tot.Inorg C(CaCO3) % Method: Fluoride (Swiss standard procedure) F - Total mg/kg

5 Indicative Values ISE 946 Method: Real totals Al g/kg As mg/kg Ba mg/kg Ca g/kg Cr mg/kg Cu mg/kg Fe g/kg Hg µg/kg K mg/kg Mg mg/kg Mn mg/kg Na mg/kg Ni mg/kg P mg/kg Pb mg/kg Si g/kg Sr mg/kg Method: Acid extractable (So-called totals) Results smaller than (<) Median of < N Be mg/kg Li mg/kg Sb mg/kg Sn mg/kg Method: Extraction with boiling 2M HNO3 Mo mg/kg Method: Extraction with 0.1M NaNO3 Results smaller than (<) Median of < N Ni µg/kg Zn µg/kg

6 Indicative Values ISE 946 Method: Extraction with 0.01M CaCl2 1:10 Na mg/kg P mg/kg Method: Extraction with 1M NH4NO3 1:2.5 (w/v) (DIN 19730) Cr µg/kg Cu µg/kg Method: Other determinations Results smaller than (<) Median of < N CN - Total mg/kg Method: Water soluble 1:10 (w/v) (EN ) F mg/kg Method: Phosphorus and related analysis P - Olsen (as P) mg/kg

7 Method: Real totals Be mg/kg Br mg/kg Cd mg/kg Co mg/kg F mg/kg Ga mg/kg I mg/kg Li mg/kg Mo mg/kg Rb mg/kg S mg/kg Sb mg/kg Sn mg/kg Y mg/kg Zr mg/kg Informative Values ISE 946 Method: Acid extractable (So-called totals) Results smaller than (<) Median of < N F mg/kg Ga mg/kg Mo mg/kg Se mg/kg Si g/kg Tl mg/kg Y mg/kg Zr mg/kg Method: Extraction with boiling 2M HNO3 Tl mg/kg Method: Extraction with 0.1M NaNO3 Results smaller than (<) Median of < N Cd µg/kg Pb µg/kg

8 Method: Extraction with 0.01M CaCl2 1:10 B µg/kg Cu µg/kg Fe mg/kg Mn mg/kg N total soluble mg/kg Ni µg/kg Zn µg/kg Informative Values ISE 946 Method: Extraction with 1M NH4NO3 1:2.5 (w/v) (DIN 19730) Results smaller than (<) Median of < N As µg/kg Cd µg/kg Hg µg/kg Ni µg/kg Pb µg/kg Tl µg/kg Zn µg/kg Method: Soil characteristics Fraction < 63 µm % Fraction > 63 µm % Method: Other determinations CN - Free mg/kg Method: Phosphorus and related analysis P - Bray (as P) mg/kg