1. 1st ANFEC Training workshop On Environmental Contaminant Analysis 18-20 December, 2012 at Royal University of Phnom Penh Royal University of Phnom Penh Organized by: Asian Network of Research on Food and Environment Contaminants (ANFEC) Supported by: Royal University of Phnom Penh, Cambodia International Science Programme, Uppsala University, Sweden.

2. Analysis of Arsenic By Silver Diethyldithiocarbamate Method Dr. Mohammad Arifur Rahman Department of Chemistry University of Dhaka Dhaka-1000 Bangladesh rmarif@univdhaka.edu

3. Arsenic determination by the silver diethyldithiocarbamate method and the elimination of metal ion interferences: By Shingara S. Sandhu Reprints from the collection of the university of Michigan Library

4. A rapid colorimetric method for measuring arsenic concentrations in groundwater R.K. Dhara,b,c, ∗, Y. Zhenga,b,c, J. Rubenstonec, A. van Geenc a School of Earth and Environmental Sciences, NSB D-216, Queens College, City University of NewYork, 65-30 Kissena Building, Flushing, NY 11367, USA b Graduate School and University Center, City University of NewYork, NY, USA c Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA Received 5 May 2004; received in revised form 16 September 2004; accepted 16 September 2004

5. Spectrometric Method of Analysis Arsine (AsH 3 ) generation followed by complexation with silver –diehyldithiocarbamate [Ag-SCSN (C2H 5 ) 2 ] solution: Arsenic reacts with a solution of Ag-DDTC, complex with morpholine in chloroform to form soluble red complex, which has an absorption maximum at 535 nm. Trivalent arsenic reacts with silver-diehyldithiocarbamate [Ag-SCSN(C 2 H 5 ) 2 ] to form a red color complex, which absorbs at 535 nm. Ag-DDTC + AsH 3 → As-DDTC (red color) This is one of the standard and reliable method for arsenic determination in water at the ppb (parts per billion),  g/L, level.

6. 5 valence As ion (As 5+ )+ (HCl, KI, SnCl 2 )→ 3 valence As ion (As 3+ ) By adding Zn to this solution, the arsenic is reduced further to arsenic hydride.

7. Preparation of Ag-DDTC Solution for Arsenic Adsorption The solution was prepared by dissolving 0.75 g Ag-DDTC in a solution of 1 ml of morpholine dissolved in 100 ml of chloroform. Then it was kept in a round bottom quick fitted flask covering with aluminium foil and preserved at 4 degree in a refrigerator.

8. Principle: Inorganic arsenic is reduced to arsine by zinc in acid solution in a Gutzeit generation (modified). The arsine is then passed through a scrubber containing glass wool impregnated with lead acetate solution and into an absorber tube containing Ag-DDTC.

9. Preparation of necessary Solution and Reagent Preparation of Potassium Iodide Solution 15 g potassium Iodide (KI) was dissolved in 100 mL distilled de-ionized water. Preparation of Stannous Chloride 10% 10 g stannous chloride (SnCl 2.2H 2 O) was dissolved in 100 mL distilled de- ionized water.

10. Preparation of Stand Standard Curve for Arsenic Measurement: Standard curve was prepared for total arsenic in concentration 5, 10, 15, 20 and 40 ppb. Then the standard curve was prepared plotting the amount of arsenic (in ppb) along X axis and absorbance along Y-axis. The arsenic content of water was then measured with the help of the curve.

11. Procedure Treatment of Sample 50 mL sample was taken into a clean generator bottle (quick fitted 100 ml conical flask) adding successively, 5 mL 1:1 HCl, 5 mL KI (15%) solution and 8 drops SnCl2 reagent. Preparation of Scrubber and Absorber Cotton was impregnated in the scrubber with lead acetate solution and 4 mL Ag- DDTC reagent was taken with a pipette in absorber tube. Arsenic Generation and Measurement Adding 1g Zn-dust to generator, it was connected with scrubber absorber immediately. All connection must be fitted tightly. Allowing 30 min, for complete evolution of arsine and pouring solution absorber into a 1 cm cell, the absorbance was measured at 540 nm, using the reagent blank as the reference.