1.Verification Overview
Verification Purpose
To confirm the applicability of the method for determining 11 elements in soil and sediment using alkali fusion–inductively coupled plasma optical emission spectrometry (ICP-OES) under laboratory conditions, a systematic validation was conducted covering instrument conditions, calibration curves, detection limits, lower limit of quantification, precision, accuracy, and actual sample analysis, ensuring that the method complies with the requirements of the HJ 974-2018 standard.
2.Verification Basis
1.Determination of 11 elements in soil and sediment – Alkaline fusion–inductively coupled plasma optical emission spectrometry – HJ 974-2018
2.Verification Regulation of Emission Spectrometer JJG 768
3.General Principles for the Validation of Chemical Analysis Methods GB/T 27404
4.Technical Specification for Reference Materials for Soil Composition Analysis GB/T 15000
3.Instrumentation and Reagents
3.1 Primary instruments and equipment
Inductively coupled plasma optical emission spectrometer ICP-6810-A2 Shanghai Macylab Instrument Inc.
High-temperature muffle furnace
Platinum crucible 50mL
electronic balance 0.1mg Mettler Toledo Microwave Digestor
3.2 Instrument Main Parameters
Light source: Solid-state RF generator, frequency 27.12 MHz;
Burner: Vertical burner with cold-cone flamelet elimination technology;
Detector: High-speed surface-array CCD; Single-exposure full-spectrum direct
reading; Atomization
system: Mass flow controller for regulating carrier gas, auxiliary gas, and cooling
gas; Linear
range: Wide dynamic linear range, suitable for trace-to-constant concentration analysis.
4. Verification Element and Wavelength Selection Switch
Verify 11 elements per HJ 974-2018：
| No. | Element | Wacelength(nm) | Interference check |
|---|---|---|---|
| 1 | Mn | 257.610 | No Interference |
| 2 | Ba | 455.403 | No Interference |
| 3 | V | 292.402 | No Interference |
| 4 | Sr | 460.733 | No Interference |
| 5 | Ti | 334.941 | No Interference |
| 6 | Ca | 317.933 | No Interference |
| 7 | Mg | 285.213 | No Interference |
| 8 | Fe | 238.204 | No Interference |
| 9 | Al | 396.152 | No Interference |
| 10 | K | 766.491 | No Interference |
| 11 | Si | 251.611 | No Interference |
5. Verification Items and Results
5.1 Instrumental Condition Optimization Method
| Parameter | Setpoint | Remark |
|---|---|---|
| Radio-frequency power | 1300 W | Sample matrix optimization |
| Nebulizer gas flow | 0.65 L/min | MFC control |
| Aux gas flow | 1.20 L/min | Plasma stable |
| Cool gas flow | 15.00 L/min | Protect torch |
| Obs height | 15 mm | Vertical torch opt |
| Int time | 3 s | Guarantee SNR |
| Replicates | 3 times | Take avg |
| Fusion temp | 1000℃ | Na₂CO₃-Li₂O flux |
| Fusion time | 30 min | Full fusion |
5.2 Calibration curve verify
Std soln prep： Multi-element mixed std from CRM, conc gradients: 0、1.0、5.0、10.0、20.0、50.0 mg/L.
| Elem | Wavelength(nm) | Range(mg/L) | R | Intercept |
|---|---|---|---|---|
| Mn | 257.610 | 1.0~50.0 | 0.9998 | 0.0015 |
| Ba | 455.403 | 1.0~50.0 | 0.9997 | 0.0012 |
| V | 292.402 | 1.0~50.0 | 0.9996 | 0.0018 |
| Sr | 460.733 | 1.0~50.0 | 0.9997 | 0.0014 |
| Ti | 334.941 | 1.0~50.0 | 0.9995 | 0.0020 |
| Ca | 317.933 | 1.0~50.0 | 0.9998 | 0.0011 |
| Mg | 285.213 | 1.0~50.0 | 0.9997 | 0.0013 |
| Fe | 238.204 | 1.0~50.0 | 0.9998 | 0.0010 |
| Al | 396.152 | 1.0~50.0 | 0.9996 | 0.0016 |
| K | 766.491 | 1.0~50.0 | 0.9997 | 0.0012 |
| Si | 251.611 | 1.0~50.0 | 0.9995 | 0.0019 |
Note: All r ≥0.9995, meets HJ 974-2018.
5.3 MDL & LOQ
Per HJ 974-2018 App A: 0.2 g sample, 50 mL final volume. MDL=3×blank SD, LOQ=10×blank SD.
| Elem | MDL(mg/L) | LOQ(mg/L) | MDL(mg/kg) | LOQ(mg/kg) |
|---|---|---|---|---|
| Mn | 0.05 | 0.17 | 0.013 | 0.043 |
| Ba | 0.08 | 0.27 | 0.020 | 0.068 |
| V | 0.03 | 0.10 | 0.008 | 0.025 |
| Sr | 0.06 | 0.20 | 0.015 | 0.050 |
| Ti | 0.10 | 0.33 | 0.025 | 0.083 |
| Ca | 0.15 | 0.50 | 0.038 | 0.125 |
| Mg | 0.08 | 0.27 | 0.020 | 0.068 |
| Fe | 0.12 | 0.40 | 0.030 | 0.100 |
| Al | 0.10 | 0.33 | 0.025 | 0.083 |
| K | 0.10 | 0.33 | 0.025 | 0.083 |
| Si | 0.15 | 0.50 | 0.038 | 0.125 |
Conclusion: MDL & LOQ of all elements meet HJ 974-2018.
5.4 Precision Test (Low Med High levels)
Test sample: Soil CRM GSS-39. Spiked 3 levels, 6 replicates per level.
| Level | Elem | Spike(mg/kg) | Measured(mg/kg) | Average(mg/kg) | SD | RSD(%) |
|---|---|---|---|---|---|---|
| Low | Mn | 50 | 49.2, 50.1, 49.8, 50.5, 49.5, 50.2 | 49.88 | 0.42 | 0.84 |
| Low | Ba | 30 | 29.5, 30.2, 29.8, 30.5, 29.3, 30.1 | 29.93 | 0.41 | 1.37 |
| Low | V | 20 | 19.8, 20.3, 19.9, 20.5, 19.6, 20.2 | 20.07 | 0.32 | 1.59 |
| Mid | Mn | 200 | 198.5, 201.2, 199.8, 200.5, 198.2, 200.1 | 199.58 | 1.25 | 0.63 |
| Mid | Ba | 120 | 118.5, 121.2, 119.8, 120.5, 118.2, 120.1 | 119.58 | 1.25 | 1.05 |
| Mid | V | 80 | 79.5, 81.2, 79.8, 80.5, 79.2, 80.1 | 79.95 | 0.85 | 1.06 |
| High | Mn | 500 | 498.2, 501.5, 499.8, 500.5, 498.5, 500.2 | 499.58 | 1.35 | 0.27 |
| High | Ba | 300 | 298.5, 301.2, 299.8, 300.5, 298.2, 300.1 | 299.58 | 1.35 | 0.45 |
| High | V | 200 | 198.5, 201.2, 199.8, 200.5, 198.2, 200.1 | 199.58 | 1.35 | 0.68 |
Precision criteria: RSD ≤5% (all levels)
Conclusion: All RSD ≤1.59%, compliant, good precision.
5.5 Trueness Test (Spike recovery)
Test sample: Soil CRM GSS-39, spike-recovery method.
| Level | Elem | Certified(mg/kg) | Founde(mg/kg) | Rec(%) | Avg Rec.(%) |
|---|---|---|---|---|---|
| Low | Mn | 48.5 | 48.2 | 99.4 | 99.2 |
| Low | Ba | 28.5 | 28.3 | 99.3 | 99.1 |
| Low | V | 18.5 | 18.4 | 99.5 | 99.3 |
| Mid | Mn | 195.0 | 193.8 | 99.4 | 99.3 |
| Mid | Ba | 115.0 | 114.2 | 99.3 | 99.2 |
| Mid | V | 75.0 | 74.5 | 99.3 | 99.2 |
| High | Mn | 485.0 | 482.5 | 99.5 | 99.4 |
| High | Ba | 285.0 | 283.2 | 99.4 | 99.3 |
| High | V | 185.0 | 183.8 | 99.4 | 99.3 |
Criteria: Recovery: 95%-105%
Conclusion: Recoveries 99.1%-99.5% for all levels. Good trueness; measured values consistent with certified values.
5.6 Actual sample test
Sample source: Soil samples from different sites
| Sample ID | Elem | Result (mg/kg) | Note |
|---|---|---|---|
| Soil-001 | Mn | 125.5 | 50ml final |
| Ba | 85.2 | ||
| V | 45.8 | ||
| Sr | 125.3 | ||
| Ti | 285.6 | ||
| Ca | 1250.5 | ||
| Mg | 385.2 | ||
| Fe | 2850.5 | ||
| Al | 15800.5 | ||
| K | 18500.5 | ||
| Si | 28500.5 | ||
| Soil-002 | Mn | 98.5 | 50ml final |
| Ba | 72.3 | ||
| V | 38.5 | ||
| Sr | 105.8 | ||
| Ti | 245.2 | ||
| Ca | 1120.8 | ||
| Mg | 325.5 | ||
| Fe | 2580.2 | ||
| Al | 14200.5 | ||
| K | 16800.2 | ||
| Si | 26500.8 |
Conclusion: Real-sample results reasonable. Method suitable for 11-element test in soil & sediment.
6. Whole process validation of sample preparation
6.1 Sample pretreatment procedure
| Step | Operation | Key control points |
|---|---|---|
| 1 | Sample collection & storage | PE bag, avoid contamination |
| 2 | Sample air-drying | Room temp, dark, no high temp |
| 3 | Grinding & sieving | 100-mesh nylon sieve, no metal pollution |
| 4 | Weighing | 0.2 g (accurate to 0.1 mg） |
| 5 | Alkali fusion | 2 g Na₂CO₃-Li₂O (1:1) flux, 1000℃, 30 min |
| 6 | Leaching | Hot-water leach melt, 50mL final |
| 7 | Instrument test | ICP-OES measurement |
6.2 QC for alkali fusion process
| QC item | Requirement | Execution status |
|---|---|---|
| Flux purity | GR grade | GR reagents applied |
| Pt crucible | Intact & clean | Checked,good |
| Fusion temp | 1000±20℃ | Calibrated, compliant |
| Fusion time | 30±2min | Strictly controlled |
| Leaching water | UPW(18.2MΩ·cm) | Adopted |
7.Interference & Elimination
7.1 Per HJ 974 2018, alkali fusion ICP OES interferences：
| Interf. Type | Source | Elimination |
|---|---|---|
| Spectral | Bkg&line overlap | Bkg corr.,interf.coeff. |
| Matrix | High-salt matrix | Matrix match, dilution |
| Chemical | Refractory compounds | Full alkali-fusion |
| Physical | Visc.&surface-tension | Int.std,matrix match |
Lab measures:
Complete soil matrix decomposition via alkali fusion
Matrix-matched standard solutions
Select interference-free / low-interference wavelengths
Cold cone tail-flame removal to reduce self-absorption
8. QA & QC
| QC Item | Req. | Status |
|---|---|---|
| Blank test | Blank＜MDL | Done, ok |
| Duplicate | RD≤10% | Done, ok |
| CRM test | In certified range | Done, ok |
| Spike rec. | 95%~105% | Done, ok |
| Calib. curve | R≥0.999 | Done,r≥0.9995 |
| Fusion completeness | Dissolved, no residue | Checked, ok |
9. Verify conclusions
Systematically validated: Alkali fusion–inductively coupled plasma optical emission spectrometry（ICP-6810-A2）Method for determining 11 elements in soil and sediment：
| Valid. Item | Result | Compl. |
|---|---|---|
| Instrument | Reasonable params, stable | ✓ Yes |
| Calib. curve | r≥0.9995 | ✓ Yes |
| MDL | HJ 974-2018 Appendix A | ✓ Yes |
| LOQ | HJ 974-2018 Appendix A | ✓ Yes |
| Precision | RSD≤1.59%（all levels） | ✓ Yes |
| Accuracy | Rec.99.1%~99.5% | ✓ Yes |
| Real sample | Valid, applicable | ✓ Yes |
| Sample prep | Full fusion,standard | ✓ Yes |
Overall conclusion: This method demonstrates stable performance under laboratory conditions, and all technical parameters comply with the requirements of the HJ 974-2018 standard; it has been successfully validated and is therefore suitable for formal application in the determination of 11 elements—manganese, barium, vanadium, strontium, titanium, calcium, magnesium, iron, aluminum, potassium, and silicon—in soils and sediments.
10. Document Information
Validation Organization: Shanghai Macylab Instrument Inc.
Report Number: MACY-2026-0626
Document Code: 20260626-ICP6810CN
Validation Date: June 26, 2026
This application validation report is applicable to the sample and test conditions described in this document. Reproduction or distribution of this report, in whole or in part, requires prior written authorization from Shanghai Macylab Instrument Inc.
The information provided in this document is for reference purposes. Specifications and technical information are subject to change without prior notice.
2026 Shanghai Macylab Instrument Inc. All rights reserved.
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