WAGENINGEN EVALUATING PROGRAMS
FOR ANALYTICAL LABORATORIES
Certificate of Analysis
International Biomass Exchange Program
REFERENCE MATERIAL
BIMEP sample 432
Certificate of Analysis
BIMEP 432
General Information
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.
All values, expressed on a weight basis (kg or %), are reported in ovendry (105 °C) material. Moisture
is reported in the material as received.
Sample information
WEPAL reference materials are from natural sources only. There is no spiking, mixing or other
o
alterations of the samples. For sample preparation the BIMEP samples are dried at 40 C and milled
to pass a 0.5 mm sieve.
This BIMEP sample 432 of Leylandcypress / Cupressus x leylandii from Wageningen / Netherlands is
prepared for the WEPAL proficiency programs. The sample is used in 2 periods (or rounds). The
results on which the values in this report are based were taken from the periods given in the following
table.
Year
2010
2016
Period
2
3
Number
2
2
1
Consensus Values
BIMEP 432
Method: General Analysis
Element
Unit
Ash
g/kg
Calorific Value (gross)
MJ/kg
Moisture
g/kg
Mean
64.4
21.4
50.0
Std.Dev.
4.57
0.36
7.38
CV %
7.1
1.7
14.7
N
19
17
20
Median
63.6
21.4
50.0
MAD
3.20
0.22
5.05
95 % confidence limits
62.2
66.6
21.18 21.55
46.6
53.5
Method: Elementary Analysis
Element
Unit
Carbon (C)
g/kg
Hydrogen (H)
g/kg
Nitrogen (N)
g/kg
Mean
514
63.5
12.5
Std.Dev.
11.3
2.56
1.22
CV %
2.2
4.0
9.8
N
19
19
18
Median
515
64.0
12.6
MAD
7.2
1.82
0.82
95 % confidence limits
509
520
62.3
64.7
11.9
13.1
2
Indicative Values
Method: General Analysis
Element
Volatile Matter
Unit
g/kg
BIMEP 432
Mean
762
Std.Dev.
11.7
CV %
1.5
N
15
Median
758
MAD
7.8
Method: Elementary Analysis
Element
Unit
Cl
g/kg
S
g/kg
Mean
1.25
0.927
Std.Dev.
0.246
0.3126
CV %
19.7
33.7
N
14
17
Median
1.31
1.010
MAD
0.165
0.2100
Method: Minor Elements
Element
Unit
Ba
mg/kg
Mn
mg/kg
Mean
12.2
15.5
Std.Dev.
2.45
7.31
CV %
20.0
47.1
N
8
8
Median
12.5
16.8
MAD
1.60
5.41
3
Informative Values
Method: Water Soluble Elements
Element
Unit
Cl
g/kg
K
g/kg
Na
g/kg
Median
1.61
7.81
0.190
MAD
-
N
1
1
1
Method: Major Elements
Element
Al
Ca
Fe
K
Mg
Na
P
Si
Unit
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
Median
0.314
18.4
0.300
6.84
0.825
0.200
1.54
1.13
MAD
0.0445
2.89
0.1650
0.700
0.1500
0.0410
0.250
0.380
N
6
6
7
6
6
5
6
6
Method: Minor Elements
Element
As
Cd
Co
Cr
Cu
F
Hg
Mo
Ni
Pb
Sb
Se
Sn
Ti
V
Zn
Unit
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Median
0.820
0.600
1.30
2.35
6.00
26.5
0.0200
0.640
1.000
1.27
0.600
0.100
0.900
22.4
0.430
16.5
MAD
0.6600
0.5100
0.200
1.650
3.300
14.50
0.0024
0.2400
0.5600
0.550
0.1000
0.8000
5.09
0.1800
5.81
N
6
5
3
4
7
4
6
3
5
4
3
1
3
4
4
8
4
BIMEP 432