APPLICATION NOTE
Tomato Leaves – NIST 1573a
SUMMARY
The application note summarizes the digestion of NIST 1573a, a tomato leaves standard reference material using ColdBlock™ Digestion Pro Series Technology.
| Instrument: | ColdBlock CBM (with quartz test tubes), chiller, ICP-MS & ICP-OES |
| Published: | July 2024 |
| Digestion Time: | 20 Minutes |
| Acid Used: | HNO3 & H2O2 |
| Average ColdBlock Recovery vs. CRM: |
|
METHODOLOGY
- Chiller temperature was set to -5°C
- 5g of each sample was weighed and placed into a quartz ColdBlock™ Digestion vessel
- 10 mL of HNO3 was added
- Sample was digested at 65% power for 20 minutes
- 2mL of ≥ 30% H2O2 was added slowly
- Samples were cooled and bulked to 40mL using 2% HNO3 v/v
DISCUSSION
- Samples were digested in triplicate
- Samples were filtered prior to analysis by ICP-MS & OES
- The NIST methods used for determination of certified Aluminum values included INAA & wet ashing with HNO3/ HF/HClO4, so Aluminum recovered low (~60%) using HNO3 & H2O2
- To improve the recovery the Aluminum, a second method was examined that included the addition of 1mL HF (10mL HNO3 + 1mL HF 65% power for 20 minutes, then slowly add 2mL of 30% H2O2) See Table 2 for results
- NIST 1573a consists of dried tomato leaves
NIST 1573a after bulk up to 40mL
Results
|
Table 1 – Results of HNO3 & H2O2 digestion – NIST 1573a Tomato Leaves |
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|
Method: |
0.5g |
10mL HNO3 65% power for 20 minutes, then slowly add 2mL of 30% H2O2 |
|||||||
|
Element |
Consensus Value (ppm) |
+/- |
Sample A |
Sample B |
Sample C |
Average (ppm) |
Stdev |
RSD |
Recovery |
|
As |
0.1126 |
0.0024 |
0.1276 |
0.1272 |
0.1108 |
0.1 |
0.0078 |
6.4% |
108% |
|
B |
33.13 |
0.42 |
33.19 |
34.81 |
32.17 |
33.39 |
1.09 |
3.3% |
101% |
|
Ca |
50450 |
550 |
47435 |
46451 |
49915 |
47934 |
1457 |
3.0% |
95% |
|
Cd |
1.517 |
0.027 |
1.455 |
1.453 |
1.507 |
1.472 |
0.025 |
1.7% |
97% |
|
Cr |
1.988 |
0.034 |
1.947 |
1.849 |
1.844 |
1.880 |
0.047 |
2.5% |
95% |
|
Cu |
4.7 |
0.14 |
4.57 |
4.78 |
4.80 |
4.7 |
0.1 |
2.2% |
100% |
|
Fe |
367.5 |
4.3 |
351.8 |
401.0 |
380.2 |
377.7 |
20.2 |
5.3% |
103% |
|
Hg |
0.0341 |
0.0015 |
0.0413 |
0.0415 |
0.0412 |
0.0413 |
0.0001 |
0.3% |
121% |
|
K |
26760 |
480 |
25391 |
26497 |
28696 |
26861 |
1374 |
5.1% |
100% |
|
Mn |
246.3 |
7.1 |
235.1 |
249.5 |
268.0 |
250.9 |
13.5 |
5.4% |
102% |
|
Na |
136.1 |
3.7 |
126.4 |
145.7 |
146.6 |
139.6 |
9.3 |
6.7% |
103% |
|
P |
2161 |
28 |
2138 |
2200 |
2230 |
2189 |
38.3 |
1.7% |
101% |
|
Rb |
14.83 |
0.31 |
13.03 |
14.34 |
14.17 |
13.85 |
0.58 |
4.2% |
93% |
|
Sb |
0.0619 |
0.0032 |
0.0567 |
0.0578 |
0.0567 |
0.0571 |
0.0005 |
0.9% |
92% |
|
V |
0.835 |
0.034 |
0.853 |
0.804 |
0.854 |
0.837 |
0.023 |
2.8% |
100% |
|
Zn |
30.94 |
0.55 |
30.60 |
28.33 |
31.49 |
30.14 |
1.3 |
4.4% |
97% |
|
Table 2 – Results of HNO3 + HF & H2O2 digestion (to improve recovery of Aluminum) |
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|
Method: |
0.5g |
10mL HNO3 + HF 65% power for 20 minutes, then slowly add 2mL of 30% H2O2 |
|||||||
|
Element |
Consensus Value (ppm) |
+/- |
Sample A |
Sample B |
Sample C |
Average (ppm) |
Stdev |
RSD |
Recovery |
|
Al |
598.4 |
7.1 |
522.5 |
538.3 |
539.1 |
533.3 |
7.6 |
1.4% |
89% |
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