APPLICATION NOTE

Zinc Concentrate, CZn-4

SUMMARY

The application note summarizes the digestion of CZn-4, a zinc concentrate certified reference material using ColdBlock Digestion Pro Series Technology.

Instrument: ColdBlock CBM Pro-Series, chiller, HF liners, ICP-OES
Published: May 2025
Digestion Time: 30 Minutes
Acid Used: HNO3, HCl, HF & H3BO3
Average ColdBlock Recovery vs. CRM:
  • 102% lead
  • 96% silver
  • 101% zinc

METHODOLOGY

  1. Set the chiller temperature to -5°C.
  2. Weigh 0.25 g of each sample and transfer into a ColdBlock Digestion vessel with liner
  3. Add 20 mL of aqua regia (add HNO3 first, followed by HCl) and 3 mL of HF to each vessel.
  4. Digest samples at 80% power for 20 minutes.
  5. Add 20 mL of 4% boric acid (w/v) to each sample.
  6. Digest samples again at 80% power for 10 minutes.
  7. Cool the samples and adjust the volume to 50 mL with DI water

DISCUSSION

  • The addition of boric acid aids in the re-solubilization of insoluble fluorides and neutralizes residual hydrofluoric acid (HF). This step is crucial for sample dissolution and minimizing analyte loss during digestion.
  • Following the digestion process, the samples were visibly clear – indicating that the sample matrix had dissolved. A trace amount of material settled on the bottom of the tube

Figure 1- CZn-4 after bulking-up to 50mL

Results

CZn-4, Zinc Concentrate

Method:

0.25g – Add 20mL aqua regia + 3mL HF and digest at 80% power for 20 minutes. Add 20mL of 4% boric acid w/v
and digest again at 80% power for 10 minutes. Let cool, and adjust the volume to 50mL with DI water

Element

CZn-4
Certified Values

ColdBlock Average n=5

ColdBlock Stdev +/–

ColdBlock RSD

ColdBlock Recovery vs Certified Value

Ag (µg/g)

51.4

49.1

1.5

3.1%

96%

Al (%)

0.0715

0.0740

0.0030

4.1%

103%

As (%)

0.0356

0.0342

0.0007

2.0%

96%

Cd (%)

0.2604

0.2713

0.004

1.3%

104%

Co (µg/g)

93.5

99.3

1.6

1.6%

106%

Cu (%)

0.403

0.4032

0.005

1.2%

100%

Pb (%)

0.1861

0.1898

0.0025

1.3%

102%

Fe (%)

9.02

9.03

0.08

0.9%

100%

S (%)

33.07

32.36

0.82

2.5%

98%

Se (µg/g)

86.7

83.8

4.7

5.6%

97%

Zn (%)

55.24

55.83

0.81

1.5%

101%

Click here to download the Application Note in PDF format.

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ColdBlock Technologies Inc.
4551 Zimmerman Ave
Niagara Falls, ON L2E 3M5
info@coldblock.ca