Method Overview
This document details the Silver Diethyldithiocarbamate Method 8013 for the quantitative analysis of arsenic in water, wastewater, and seawater. The method is adapted from Standard Methods for the Examination of Water and Wastewater and is USEPA accepted for reporting for drinking and wastewater analysis.
The procedure involves a distillation process to separate arsenic as arsine gas, followed by reaction with silver diethyldithiocarbamate to form a red complex, which is then measured colorimetrically at a wavelength of 520 nm.
Scope and Application
This method is suitable for determining arsenic concentrations ranging from 0 to 0.200 mg/L As. Distillation is a required step for accurate results.
Instrument Compatibility
The test can be performed using various Hach spectrophotometers, including the DR 6000, DR 3800, DR 2800, DR 2700, DR 1900, DR 5000, and DR 3900. Specific instrument-specific information regarding sample cell orientation and requirements is provided.
Key Procedural Steps
- Test Preparation: Includes setting up the distillation apparatus in a fume hood and reviewing Safety Data Sheets (SDS) for proper chemical handling and personal protective equipment.
- Sample Collection and Storage: Guidelines for collecting and preserving samples to maintain arsenic integrity, including pH adjustment and storage conditions.
- Reagent Preparation: Instructions for preparing the arsenic absorber solution and standard solutions for calibration.
- Calibration: Details on creating a user-prepared calibration curve within the instrument, including entering standard concentrations and performing measurements.
- Test Procedure: A step-by-step guide for conducting the analysis, from preparing the distillation apparatus to reading the results on the spectrophotometer.
- Interferences: Information on potential interfering substances, such as Antimony Salts, which can affect color development.
Consumables and Required Apparatus
A comprehensive list of required reagents, consumables, and apparatus is provided, including specific item numbers for ordering from Hach. This includes standard solutions, acids, reagents, glassware, and analytical instruments.
Contact Information
For technical assistance, price information, and ordering, contact Hach Company directly. In the U.S.A., call toll-free at 800-227-4224. Outside the U.S.A., contact the local Hach office or distributor. Further information is available on the Hach website at www.hach.com.
