- What it is. This sodium sulfate is anhydrous ACS reagent grade, supplied in a 2.5 kg size. It is a high-purity, neutral salt used to dry organic extracts in analytical work, prepare sulfate standards, and support laboratory applications that require documented impurity limits.
- What ACS grade guarantees. ACS reagent anhydrous sodium sulfate assays at 99.0% minimum, with limits of 0.01% insoluble matter, 0.5% loss on ignition, 0.001% each of chloride, phosphate, and iron, 5 ppm each of nitrogen compounds and heavy metals, and limits on calcium, magnesium, and potassium. A 5% solution has a pH of 5.2-9.2.
- Why purity matters for drying agents. In trace analysis, impurities in the drying agent can leach into extracts and appear as contaminants. ACS grade limits those impurities, and specially tested grades are used for pesticide residue analysis where even trace organics would interfere.
- Drying chemistry. Anhydrous sodium sulfate absorbs water by forming the decahydrate, Na2SO4·10H2O. It is neutral and inert toward most organic compounds, has high capacity, and filters easily, making it a standard drying agent in extraction workups.
- Analytical sample preparation. In environmental and food methods, extracts are often passed through an anhydrous sodium sulfate column to remove residual water before concentration and chromatographic analysis.
- Chemical identity. Anhydrous sodium sulfate (CAS 7757-82-6, Na2SO4, 142.04 g/mol) melts at about 888 °C, boils at about 1429 °C, and has a density of about 2.7 g/cm³.
- Size for regular use. The 2.5 kg size suits labs that dry extracts routinely or prepare drying columns, providing one consistent lot over an extended period. For general drying, Lab Pro also stocks Sodium Sulfate, Anhydrous, 1 kg.
- Preparing sulfate standards. Dried ACS sodium sulfate can be used to prepare sulfate calibration standards for ion chromatography and turbidimetric sulfate methods, since its sulfate content is known from its high assay.
- Storage. Anhydrous sodium sulfate absorbs moisture from the air, which reduces its drying capacity. Keep the container tightly closed, and for critical work, heat the salt to drive off absorbed water before use.
Technical Specifications
| Chemical Name | Sodium sulfate, anhydrous |
| CAS Number | 7757-82-6 |
| EC Number | 231-820-9 |
| Synonyms | Disodium sulfate, thenardite (mineral), salt cake |
| Formula | Na2SO4 |
| Molecular Weight | 142.04 g/mol |
| Form | White powder or granules, anhydrous |
| Melting Point | About 888 °C |
| Density | About 2.7 g/cm³ |
| Grade | ACS reagent |
| Assay | 99.0% min |
| pH (5% solution, 25 °C) | 5.2 to 9.2 |
| Insoluble Matter | 0.01% max |
| Loss on Ignition | 0.5% max |
| Chloride (Cl) | 0.001% max |
| Phosphate (PO4) | 0.001% max |
| Nitrogen Compounds (as N) | 5 ppm max |
| Heavy Metals (as Pb) | 5 ppm max |
| Iron (Fe) | 0.001% max |
| Calcium (Ca) | 0.01% max |
| Magnesium (Mg) | 0.005% max |
| Potassium (K) | 0.01% max |
| Boiling Point | About 1429 °C |
| Package Size | 2.5 kg |
Applications / Common Uses
- Extract drying: Removes water from organic extracts.
- Drying columns: Prepares sodium sulfate columns for sample cleanup.
- Environmental analysis: Dries extracts before chromatography.
- Sulfate standards: Prepares sulfate calibration standards.
- Reagent preparation: Supplies high-purity sulfate.
Storage, Handling & Shipping
Store tightly closed in a dry place at room temperature. Anhydrous sodium sulfate readily absorbs moisture, reducing its drying capacity, so keep the container sealed and reseal it immediately after use.
- Incompatible materials: Strong acids, aluminum, and magnesium at high temperatures.
- Personal protection: Safety glasses, gloves, and dust control.
- Spill response: Sweep up without raising dust and place in a closed container.
- First aid: Eyes: rinse with water for several minutes.
Related Categories & Services
- Shop ACS Grade Laboratory Chemicals for related products in this category.
- Explore Inorganic Chemicals and Solvents.
- Vendor Managed Inventory (VMI) Program: Lab Pro can stock, track, and replenish this item on site so it never runs out. Contact info@labproinc.com or 888-452-2776 to set up a VMI assessment.
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FAQs
What does ACS grade mean for sodium sulfate?
ACS grade anhydrous sodium sulfate meets American Chemical Society requirements: at least 99.0% assay, a 5% solution pH of 5.2 to 9.2, and limits on insoluble matter, chloride, phosphate, nitrogen compounds, heavy metals, iron, and alkali metals. It suits analytical work that needs documented purity.
Why use ACS sodium sulfate for drying extracts?
Impurities in a drying agent can leach into extracts and show up during analysis. ACS grade limits those impurities, keeping blanks clean. For pesticide residue work, specially tested grades screened for organic contaminants may be required by the method. Check your method's grade requirement before purchasing for regulated analyses.
How is sodium sulfate used in a drying column?
Pack a glass column or funnel with a plug of glass wool and a layer of anhydrous sodium sulfate, then pass the organic extract through it. The salt retains water while the dried extract flows through for concentration and analysis. Rinse the column with clean solvent.
How should anhydrous sodium sulfate be stored?
Keep it tightly closed in a dry place at room temperature, since it absorbs moisture from the air. For critical analytical work, heat the salt to drive off absorbed water and cool it in a desiccator before use to restore full drying capacity. Label the drying date.
What is the difference between the 1 kg and 2.5 kg sodium sulfate products?
The 2.5 kg product is ACS reagent grade with documented impurity limits, suited to analytical sample preparation. The 1 kg product is anhydrous sodium sulfate for general drying, with grade to be confirmed. Choose ACS grade when trace impurities could affect results. Both are anhydrous.
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