Develonutri
Protocol for DEVELONUTRI mineral ring test (tomato, potato and wheat samples)
1. Preparation of the samples
 Prior to digestion dry the samples at 100°C for 24 h
 Weigh approximately 500 mg per sample
 Make 3 repetitions per sample
 Wash all material with HNO3 and HCl prior to use
 In addition to the crop samples weigh in 3 times 500 mg of the NIST 1568a
standard which I will distribute to you
2. Digestion procedure
 Add 3 ml of HNO3 and 1 ml of H2O2 to each digestion vessel
 Use the following microwave program:
 Heat to 70°C in 20 minutes
 Heat to 130°C in 40 minutes
 Heat to 200°C in 30 minutes
 Leave at 200°C for 20 minutes
 Add an internal Ytrium standard (10 ppm) to every sample
 Dilute the digested samples with 0.1% HNO3 to a volume of 25 ml
3. ICP-OES measurements (ICP-MS used manufacturer settings)
a. Measure each mineral at least at two different wavelengths (at the one indicated below
and at a second one depending on your machine and your preference)
b. Make three technical replicates/measurement
Element
Ca
Cu
Fe
K
Mg
Mn
Mo
Na
P
Zn
4.
a.
i.
ii.
Wavelength
(nm)
315.887
324.754
238.204
769.896
279.553
257.610
202.032
588.995
178.287
213.856
Analyzing the data
Use the following formulas to determine the limits of detection and quantification
Limit of detection: 3*stdev (blind)/slope (calibration line)
Limit of quantification: 10*stdev (blind)/slope (calibration line)
The above protocol for the analysis of minerals was developed and distributed to all the
partners involved in this activity. The elements measured were Cu, Ca, Fe, K, Mg, Mn,
Na, P, Zn. Since the Se and Mo concentrations were too low to be detectable with ICPOES, they were omitted from the SOP. Homogenous samples have been distributed with
samples of wheat, lyophilized tomato and potato samples, plus aliquots of the NIST rice
standard
1568a
(https://wwws.nist.gov/srmors/certificates/view_cert2pdf.cfm?certificate=1568A).
Develonutri
NIS T meas urements
Mg
414
450
598
505
521
537
504 13%
560
1674
1530
11%
R
T
I
F
G
S
average
Nist
71
8.4
4.1
17.7
18.8
6.6
R
T
I
F
G
S
average
Nist
138%
Fe
1024
1240
1099
1248
815
1085
1280
R
T
I
F
G
S
average
Nist
16%
14
19
21
20
19
19
19
20
R
T
I
F
G
S
average
Nist
Cu (ppm)
6.4
5.5
Mn (ppm)
1802
1602
1370
1635
K
K (ppm)
Mg (ppm)
R
T
I
F
G
S
average
Nist
R
T
I
F
G
S
average
Nist
Cu
13%
Zn
6.3
8
14
7.8
11.8
7.8
9.3 32%
7.4
R
T
I
F
G
S
average
Nist
19
19
1.8
3.1
3.6
2.6
3.3
3.2
2.9 23%
2.4
Mo
17
20
21
19
19
20
R
T
I
F
G
S
average
Nist
Mo (ppm)
149 14%
118
1755
1880
MN
Zn (ppm)
179
125
160
134
R
T
I
F
G
S
average
Nist
Na
Fe (ppm)
139
158
P (ppm)
Ca (ppm)
R
T
I
F
G
S
average
Nist
P
Na (ppm)
Ca
7%
1.8
1.4
2.0
1.2
1.6 23%
1.5
R = R omania
T = T urkey
I = Italy
F = F inland
G = G reece
S = S witzerland
The selected mineral contents of the NIST rice standard (upper) and representative Ca
contents of the ring test potato, tomato and wheat material as analysed by partners P4-8 &
P10.