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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:

  • 101% Boron

  • 103% Iron

  • 101% Phosphorus

METHODOLOGY

  1. Chiller temperature was set to -5°C
  2. 0.5g of each sample was weighed and placed into a quartz ColdBlock Digestion vessel
  3. 10 mL of HNO3 was added
  4. Sample was digested at 65% power for 20 minutes
  5. 2mL of ≥ 30% H2O2 was added slowly
  6. 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 HN3/ 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

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)

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%

Click here to download the Application Note in PDF format.

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4551 Zimmerman Ave
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info@coldblock.ca.