APPLICATION NOTE

Whole Milk Powder – NIST 1549a

SUMMARY

The application note summarizes the digestion of NIST 1549a, a whole milk powder standard reference material using ColdBlock Digestion Pro Series Technology.

Instrument:

ColdBlock CBM (with quartz test tubes), chiller, ICP-MS

Published:

May 2024

Digestion Time:20 Minutes
Acid Used:HNO3 & H2O2
Average ColdBlock Recovery vs. CRM:
  • 94% Calcium

  • 99% Potassium

  • 98% Zinc

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 and mixed with the sample
  4. Sample was digested at 65% power for 20 minutes
  5. 2mL of ≥ 30% H2O2was added
  6. Samples were cooled and bulked to 40mL using 2% HNO3v/v

DISCUSSION

  • Samples were digested in triplicate
  • Samples were filtered prior to analysis by ICP-MS
  • H2O2(Sigma Aldrich 95321, Hydrogen peroxide solution ≥30%, for trace analysis)
  • HNO3 (Analytichem, 250-038-175, Nitric Acid, PP, 67-70%)
  • NIST 1549a is a whole milk powder blended and packaged by High Purity Standards (Charleston, SC).

NIST 1549a after bulk-up to 40mL

Results

NIST 1549a – Whole Milk Powder

Method:

0.5g

10mL HNO3 digested at 65% power for 20 minutes, then added 2mL H2O2,

let cool and bulked to 40mL with 2% HNO3 v/v

 

Element

NIST

Certified Values (mg/kg)

95% Confidence Limits

 

Sample A

 

Sample B

 

Sample C

 

Average (mg/kg)

 

Stdev

 

% RSD

 

%

Recovery

Low

High

Ba

0.566

0.527

0.605

0.509

0.553

0.546

0.536

0.019

3.6%

95%

Ca

8810

8570

9050

8226

8256

8348

8277

52

0.6%

94%

Mg

892

830

954

869

896

788

851

46

5.4%

95%

Mn

0.184

0.16

0.208

0.161

0.194

0.186

0.180

0.014

7.8%

98%

P

7600

7100

8100

6924

6976

7121

7007

83

1.2%

92%

K

11920

11490

12350

10731

12278

12238

11749

720

6.1%

99%

Se

0.242

0.216

0.268

0.256

0.229

0.264

0.250

0.015

6.0%

103%

Na

3176

3118

3234

3865

3180

2927

3324

396

11.9%

105%

Sr

2.14

1.95

2.33

2.23

2.15

2.00

2.13

0.10

4.5%

99%

Zn

33.8

31.5

36.1

30.0

36.9

32.3

33.1

2.9

8.7%

98%

*Cu

0.638

0.589

0.687

0.693

0.670

0.669

0.677

0.011

1.6%

106%

*Fe

1.85

1.12

2.58

1.78

1.89

1.82

1.83

0.05

2.5%

99%

*Mo

0.377

0.305

0.449

0.328

0.371

0.383

0.361

0.024

6.5%

96%

*Ni

0.068

0.054

0.082

0.064

0.054

0.082

0.067

0.012

17.4%

98%

Click here to download the Application Note in PDF format.

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