1.Validation Overview
Project Name: Method Validation for Hexavalent Chromium in Solid Waste
Reference Standard:HJ 687—2014《Solid Waste – Hexavalent Chromium, Alkaline Digestion / FAAS》
Instrument: AA-1800C Atomic Absorption Spectrophotometer
Organization:Shanghai Macylab Instrument Inc.
Date: March 05,2026
Validator: He Ke
Reviewer: Jiang Ying
Report number:MACY-2026-0305
2.Instrument Conditions
2.1 Parameters
| Parameter | Value |
|---|---|
| Parameter | 357.9 nm（Cr） |
| Spectral Bandwidth | 0.4 nm |
| Lamp Current | 6 mA |
| Burner Height | 6 mm |
| Burner | 50 mm Ti head |
| Acetylene Flow | 1.6 L/min |
| Air Flow | 8.0 L/min |
| Integration Time | 3 s |
| Reading | Peak Height |
| Replicates | 3 times, average |
2.2 Performance
| Index | Req. | Result | Conclusion |
|---|---|---|---|
| Static Baseline Drift | ≤±0.002A/30min | ±0.0010A/30min | Pass |
| Dynamic Baseline Drif | ≤±0.005A/30min | ±0.0025A/30min | Pass |
| RSD | ≤0.5% | 0.28% | Pass |
| Wavelength Accuracy | ≤0.15nm | 0.06nm | Pass |
| Characteristic Conc | ≤0.04μg/mL/1% | 0.028μg/mL/1% | Pass |
3.Calibration Curve Validation
3.1 Standard Solution Prep
Certified Cr(VI) stock (1000 mg/L), serially diluted by 0.1 mol/L NaOH：
| Std No | Conc.（mg/L） | Method |
|---|---|---|
| 0 | 0.00 | Blank（0.1 mol/L NaOH） |
| 1 | 1.00 | Serial dilution |
| 2 | 2.00 | Serial dilution |
| 3 | 4.00 | Serial dilution |
| 4 | 8.00 | Serial dilution |
| 5 | 16.00 | Serial dilution |
| 6 | 32.00 | Serial dilution |
3.2 Curve Data
| Conc.（mg/L） | A1 | A2 | A3 | Avg |
|---|---|---|---|---|
| 0.00 | 0.0010 | 0.0008 | 0.0009 | 0.0009 |
| 1.00 | 0.0352 | 0.0358 | 0.0355 | 0.0355 |
| 2.00 | 0.0708 | 0.0712 | 0.0710 | 0.0709 |
| 4.00 | 0.1415 | 0.1420 | 0.1418 | 0.1418 |
| 8.00 | 0.2832 | 0.2838 | 0.2835 | 0.2835 |
| 16.00 | 0.5658 | 0.5665 | 0.5662 | 0.5662 |
| 32.00 | 1.1285 | 1.1292 | 1.1288 | 1.1288 |
3.3 Fitting
| Param | Result |
|---|---|
| Equation | y = 0.0352x + 0.0005 |
| R | （r）0.9999 |
| Intercept | 0.0005 |
| Slope | 0.0352 |
Criterion： r ≥ 0.995
Conclusion：r = 0.9999，compliant
4. MDL & LOQ Validation
4.1 MDL Test
Per HJ 687-2014: 2.5g sample, final vol 100mL; MDL=2mg/kg, LOQ=8mg/kg.
Test：0.5 mg/L soln, 7 replicates. MDL = t×S, t=3.143(df=6)
| No. | Abs | Conc（mg/L） |
|---|---|---|
| 1 | 0.0178 | 0.505 |
| 2 | 0.0172 | 0.488 |
| 3 | 0.0182 | 0.518 |
| 4 | 0.0175 | 0.496 |
| 5 | 0.0180 | 0.511 |
| 6 | 0.0170 | 0.482 |
| 7 | 0.0176 | 0.499 |
Result：
Mean：0.500 mg/L
S：0.013 mg/L
MDL = 3.143 × 0.013 = 0.041 mg/L（soln）
Converted to solid waste：0.041 × 100 / 2.5 = 1.64 mg/kg
4.2 Lower limit determination validation
| Item | Req | Result | Conclusion |
|---|---|---|---|
| MDL | 2 mg/kg | 1.64 mg/kg | Superior |
| LOQ | 8 mg/kg | 6.56 mg/kg | Superior |
Rule: LOQ=4×MDL
Conclusion: MDL & LOQ meet HJ 687-2014.
5. Precision Validation
5.1 Test Scheme
Per HJ 687-2014: low/med/high levels, 6 replicates each.
| Conc Level | Spike（mg/kg） | Soln Conc（mg/L） |
|---|---|---|
| Low | 8.0 | 0.20 |
| Mid | 40.0 | 1.00 |
| High | 160.0 | 4.00 |
5.2 Precision Results
Low（8.0 mg/kg）
| No. | Result（mg/kg） |
|---|---|
| 1 | 8.12 |
| 2 | 8.25 |
| 3 | 8.18 |
| 4 | 8.22 |
| 5 | 8.15 |
| 6 | 8.20 |
Mean：8.18 mg/kg
S：0.048 mg/kg
RSD = 0.59%
Med（40.0 mg/kg）
| No. | Result（mg/kg） |
|---|---|
| 1 | 40.15 |
| 2 | 40.28 |
| 3 | 40.22 |
| 4 | 40.18 |
| 5 | 40.25 |
| 6 | 40.20 |
Mean：40.21 mg/kg
S：0.052 mg/kg
RSD = 0.13%
High（160.0 mg/kg）
| No. | Result（mg/kg） |
|---|---|
| 1 | 160.35 |
| 2 | 160.28 |
| 3 | 160.42 |
| 4 | 160.30 |
| 5 | 160.38 |
| 6 | 160.32 |
Mean：160.34 mg/kg
S：0.053 mg/kg
RSD = 0.03%
5.3 Precision Conclusion
| Conc Level | Spike（mg/kg） | RSD（%） | Req | Result |
|---|---|---|---|---|
| Low | 8.0 | 0.59 | ≤10% | Pass |
| Med | 40.0 | 0.13 | ≤5% | Pass |
| High | 160.0 | 0.03 | ≤5% | Pass |
HJ687-2014: RSD ≤10%(low), ≤5%(med/high).
Conclusion: 3 levels pass, precision qualified
6.Accuracy Validation（Recovery）
6.1 Scheme
Test by spike recovery using solid waste CRM.
Reference Material Information：
Reference Material Name：Standard reference material for the analysis of hexavalent chromium in industrial solid waste
CRM：RMH-G015
Cert：18.5 mg/kg
Uncert：±1.5 mg/kg
6.2 Spike RecoveryLow spike（8.0 mg/kg）
| No. | Blank（mg/kg） | Spiked（mg/kg） | Rec（%） |
|---|---|---|---|
| 1 | 0.15 | 8.22 | 101.6 |
| 2 | 0.12 | 8.18 | 101.3 |
| 3 | 8 | 8.28 | 102.0 |
| 4 | 0.14 | 8.20 | 101.4 |
| 5 | 0.6 | 8.25 | 101.8 |
| 6 | 0.13 | 8.19 | 101.3 |
Avg Rec：101.5%
Rec Range：101.3% ~ 102.0%
Med spike（40.0 mg/kg）
| No. | Blank（mg/kg） | Spiked（mg/kg） | Rec（%） |
|---|---|---|---|
| 1 | 0.18 | 40.32 | 99.8 |
| 2 | 0.15 | 40.25 | 99.6 |
| 3 | 0.20 | 40.38 | 100.0 |
| 4 | 0.17 | 40.30 | 99.9 |
| 5 | 0.19 | 40.35 | 99.9 |
| 6 | 0.16 | 40.28 | 99.7 |
Avg Rec：99.8%
Rec Range：99.6% ~ 100.0%
High spike（160.0 mg/kg）
| No. | Blank（mg/kg） | Spiked（mg/kg） | Rec（%） |
|---|---|---|---|
| 1 | 0.22 | 160.45 | 99.9 |
| 2 | 0.18 | 160.38 | 99.8 |
| 3 | 0.25 | 160.52 | 100.0 |
| 4 | 0.20 | 160.42 | 99.9 |
| 5 | 0.23 | 160.48 | 99.9 |
| 6 | 0.19 | 160.40 | 99.8 |
Acg Rec：99.9%Rec
Range：99.8% ~ 100.0%
6.3 CRM Verification
Test with solid waste CRM RMH-G015 (cert:18.5 mg/kg：
| No. | Result（mg/kg） |
|---|---|
| 1 | 18.42 |
| 2 | 18.55 |
| 3 | 18.48 |
| 4 | 18.52 |
| 5 | 18.50 |
| 6 | 18.46 |
Mean：18.48 mg/kg
Cert：18.5 mg/kg
RE：(18.48 – 18.5) / 18.5 × 100% = -0.11%
RSD：0.32%
Criterion: Measured value within certified uncertainty
Conclusion: 18.48 mg/kg falls in 18.5±1.5 mg/kg, pass.
6.4 Accuracy Conclusion
| Conc Level | Spike（mg/kg） | Avg Rec（%） | Req | Result |
|---|---|---|---|---|
| Low | 8.0 | 101.5 | 85%~115% | Pass |
| Med | 40.0 | 99.8 | 90%~110% | Pass |
| High | 160.0 | 99.9 | 90%~110% | Pass |
| CRM | 18.5（cert） | RE-0.11% | ≤10% | Pass |
Conclusion: Spike recovery & CRM test meet requirements, method accuracy qualified
7. Actual Sample Validation
7.1 Actual Sample Information
| Sample No. | Type | Location | Date |
|---|---|---|---|
| SW-2026-001 | Ind.Solid Waste | Shanghai Electroplating Plant | 2026-02-20 |
| SW-2026-002 | Ind. Solid Waste | Shanghai Chemical Plant | 2026-02-22 |
| SW-2026-003 | Gen. Solid Waste | Shanghai Ind. Park | 2026-02-25 |
7.2 Sample Test Results
| No. | Val 1（mg/kg） | Val 2（mg/kg） | Val 3（mg/kg） | Mean（mg/kg） | RSD（%） |
|---|---|---|---|---|---|
| SW-2026-001 | 25.35 | 25.48 | 25.42 | 25.42 | 0.47 |
| SW-2026-002 | 12.18 | 12.25 | 12.22 | 12.22 | 0.49 |
| SW-2026-003 | 3.85 | 3.92 | 3.88 | 3.88 | 1.03 |
7.3 Sample Spike Test
| No. | Spike Conc（mg/kg） | Spiked Val（mg/kg） | Rec（%） |
|---|---|---|---|
| SW-2026-001 | 40.0 | 65.58 | 100.4 |
| SW-2026-002 | 40.0 | 52.35 | 100.3 |
| SW-2026-003 | 40.0 | 43.92 | 100.1 |
Conclusion: Results valid. Rec 100.1%~100.4%. Method fits sample analysis
8. Full Sample Prep Validation
8.1 Sample Prep Procedure
Per HJ 687-2014, full validation including sample preparation：
Sampling & storage：Stainless sampler, sealed, 4℃, test within 7d
Pretreatment：Air-dry, grind, sieve 0.15mm, mix
Alkali digestion: 2.5g sample + 50mL 0.1 mol/L NaOH, boil bath 30min
Centrifuge: 4000 r/min, 10min
Supernatant: Direct injection
8.2 Validation Results
| Item | Content | Result | Conclusion |
|---|---|---|---|
| Sample Represent | Homogeneity test | RPD<3% | Pass |
| Extraction Eff | Spike Rec | 99.8%~101.5% | Pass |
| Operation Norm | SOP | complu with HJ 687-2014 | Pass |
| Data Integrity | Raw record traceable | Complete | Pass |
| Min Sample Mass | ≥2.5g | 2.5g | Comply |
9. Validation Conclusion
9.1 Overall Assessment
| Item | Result | Meet HJ 687-2014 |
|---|---|---|
| Instrument | Parameters reasonable,performance ok | Yes |
| Cal Curve | r = 0.9999 | Yes（r≥0.995） |
| MDL | 1.64 mg/kg | Better than std（2 mg/kg） |
| LOQ | 6.56 mg/kg | Better than std（8 mg/kg） |
| Precision | RSD = 0.03%~0.59% | Yes（≤5%~10%） |
| Accuracy | Rec99.8%~101.5% | Yes（85%~115%） |
| Real Sample | Valid test, Rec100.1%~100.4% | Yes |
| Sample Prep | Full procedure standardized | Yes |
9.2 Final Conclusion
Validated method. AA-1800C AAS for Cr(VI) in solid waste per HJ 687-2014. MDL, LOQ, precision & accuracy meet std. Full sample prep standardized, data traceable. Passed, for routine test.
Document Information
Report No.: MACY-2026-0305
Document Code: 20260305-AA1800CN
Date: March 2026
Produced by: Shanghai Macylab Instrument Inc.
2026 Shanghai Macylab Instrument Inc. All rights reserved.
The information provided in this document is for reference purposes. Shanghai Macylab Instrument Inc. makes reasonable efforts to ensure the accuracy of the information but shall not be liable for errors or for any indirect losses arising from the use of this document.
Specifications, instructions, and technical information are subject to change without prior notice.
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