Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D4839-03 – Standard Test Method Technical Guide
🧪 Scope and Applicability
This test method covers the determination of total carbon (TC), inorganic carbon (IC), and total organic carbon (TOC) in water, wastewater, and seawater. The applicable range is from 0.1 mg/L to 4000 mg/L of carbon. It is suitable for both laboratory analysis and stream monitoring. The method’s validity for untested matrices must be verified by the user, as it was successfully tested with reagent water spiked with sodium carbonate, acetic acid, and pyridine.
⚙️ Oxidation and Detection Principles
The method uses ultraviolet (UV) irradiation, persulfate chemical oxidation, or a combination of both to convert carbonaceous matter in the sample into carbon dioxide. The generated CO₂ is then measured via infrared (IR) detection. Sample introduction occurs through a syringe or injector, where the maximum particle size is limited by the needle or opening diameter.
| 🧪 Carbon Parameter | 📖 Definition | ⚖️ Range (mg/L) |
|---|---|---|
| Total Carbon (TC) | Sum of IC and TOC | 0.1 – 4000 |
| Inorganic Carbon (IC) | Carbon as CO₂, CO₃²⁻, HCO₃⁻ | 0.1 – 4000 |
| Total Organic Carbon (TOC) | Carbon in organic compounds | 0.1 – 4000 |
📊 Precision and Reference Standards
The method was validated using reagent water spiked with sodium carbonate, acetic acid, and pyridine. It references key ASTM standards for water sampling and analysis, including D1129 (Terminology), D1193 (Reagent Water), D2777 (Precision and Bias), D3370 (Sampling), and D5847 (Quality Control). Users must adhere to these standards for reliable results.
⚠️ Important Limitation: The syringe needle or injector opening size limits the maximum particle size that can be introduced into the reaction zone. Pre-screening or homogenization may be required for samples with larger particulates.
💡 Practical Tip: For refractory materials that resist complete oxidation, use a combination of UV irradiation and persulfate treatment to ensure full conversion of carbon to CO₂ before IR detection.
❓ Frequently Asked Questions
🔍 What is the difference between TC, IC, and TOC?
Total carbon (TC) is the sum of inorganic carbon (IC) and total organic carbon (TOC). IC includes carbon in carbon dioxide, carbonate, and bicarbonate forms, while TOC represents carbon derived from organic compounds.
💡 Which types of water can be analyzed with this method?
The method is applicable to fresh water, wastewater, and seawater. It has been validated with reagent water containing sodium carbonate, acetic acid, and pyridine.
⚡ What oxidation techniques are employed?
Ultraviolet (UV) irradiation, persulfate chemical oxidation, or both are used to oxidize carbon in the sample to CO₂, which is then detected by infrared (IR) analysis.
📌 What is the concentration range covered?
The test method covers carbon concentrations from 0.1 mg/L up to 4000 mg/L.