Analysis of trace antimony in water

Importance of the Topic

Antimony (Sb) is increasingly regulated as a priority water contaminant due to its widespread industrial use and toxicity, which can cause respiratory irritation, dermatitis, and cellular damage. Regulatory limits for Sb in drinking water are typically set below 6 µg L⁻¹, driving the need for analytical methods that combine sensitivity, speed, and high matrix tolerance.

Study Objectives and Overview

This study assesses the performance of the Thermo Scientific iCE 3300 Flame AAS and iCE 3400 Graphite Furnace AAS systems for Sb determination in water, in full compliance with Chinese environmental standards HJ 1046-2019 (flame AAS) and HJ 1047-2019 (graphite furnace AAS). Key goals include evaluation of detection limits, linearity, precision, accuracy, and robustness across diverse water matrices.

Methodology and Instrumentation

Water matrices evaluated include surface water, industrial wastewater, and tap water. Samples were acidified with HNO₃, and industrial effluents underwent hot-plate digestion. River samples were filtered to 0.45 µm. Calibration used Sb standards spanning the ranges required by each HJ method. Flame AAS at 217.6 nm employed D₂ background correction, optimized burner height, and air–acetylene flame. Graphite furnace AAS used matrix modifiers (Mg(NO₃)₂/Pd(NO₃)₂), deuterium correction, pyrolytic tubes, and a temperature program from drying to atomization.

Instrumentation

• Thermo Scientific iCE 3300 Flame Atomic Absorption Spectrometer with SOLAAR software
• Thermo Scientific iCE 3400 Graphite Furnace Atomic Absorption Spectrometer with SOLAAR GFTV monitoring
• IKA RCT basic IKAMAG magnetic hot-plate stirrer
• High-purity reagents and 18.2 MΩ cm deionized water

Main Results and Discussion

Flame AAS achieved a detection limit of 0.18 mg L⁻¹ (vs. 0.3 mg L⁻¹ requirement), precision RSD <0.3%, and spike recoveries of 93–101%. Graphite Furnace AAS delivered linearity over 10–150 µg L⁻¹ (R²>0.998), a detection limit of 0.3 µg L⁻¹ (<8 µg L⁻¹ requirement), repeatability RSD <3.5%, and recoveries >99%. Quality control (CCV, CCB, LCS) across 50 samples passed all HJ method criteria during a 6.5-hour continuous run.

Benefits and Practical Applications

• Rapid, cost-effective workflows for high-throughput water testing
• FL-AAS suitable for routine screening of higher Sb concentrations in industrial effluents
• GF-AAS preferred for ultratrace Sb analysis in drinking water
• Full compliance with Chinese standards HJ 1046-2019 and HJ 1047-2019
• Modular platforms support both flame and furnace methods in a compact footprint

Future Trends and Applications

Anticipated developments include hydride generation accessories to further lower detection limits, automation and in-line coupling with separation techniques for speciation, remote or real-time monitoring sensors, and expanded application in environmental fate and transport studies.

Conclusion

Both flame and graphite furnace AAS platforms deliver reliable, sensitive Sb quantification in water, fully meeting HJ 1046-2019 and HJ 1047-2019 performance requirements. They offer laboratories flexible, efficient solutions for trace and ultratrace antimony analysis across varied water matrices.

Reference

• Winship KA. Toxicity of antimony and its compounds. Adverse Drug React Acute Poisoning Rev. 1987;2:67–90.
• U.S. EPA Method 204.2. Determination of antimony by GF-AAS.
• HJ 1046-2019 Water Quality – Determination of antimony – Flame atomic absorption spectrometry.
• HJ 1047-2019 Water Quality – Determination of antimony – Graphite furnace atomic absorption spectrometry.