Download Standard Operation Procedure - Ru

Standard Operation Procedure for detection of Cacium in water;
Procedure for Operation and Calibration of Calcium determination in Water
PURPOSE:
 To establish a procedure for Calcium determination in water.
SCOPE AND APPLICATION:
 This method is based on Standard Methods 3500-Ca B EDTA titrimetric method and is
applicable to ground, drinking, surface, and saline waters, domestic and industrial wastes.
RESPONSIBILITY:
 WQL Analyst: Operation and Calibration.

WQL Manager: Receiving sample & log book entry and Implementation of this SOP.

WQ Consultant: QC/QA.
PRINCIPLE & SUMMARY OF METHOD:
When EDTA (ethylene di amine tetra acetic acid or its salts) is added to water containing both
calcium and magnesium, it combines first with the calcium. Calcium can be determined directly,
with EDTA, when the pH is made sufficiently high that the magnesium is largely precipitated as the
hydroxide and an indicator is used that combines with calcium only. Several indicators give a color
change when all of the calcium has been complexed by the EDTA at a pH of 12 to 13.
HEALTH AND SAFETY WASTE HANDLING:
 Wear personal protective equipment (PPE) including lab coat, safety glasses, and gloves when
performing analysis.

After analysis discard analyzed samples down the drain. Retain unused sample until the
sample has been reviewed and reported.
INTERFERENCES:
 Under conditions of this test, the following concentrations of ions cause no interference with
the calcium determination: Cu2+, 2 mg/L; Fe2+, 20 mg/L; Fe3+, 20 mg/L; Mn2+, 10 mg/L; Zn2+,
5 mg/L; Pb2+, 5 mg/L; Al3+, 5 mg/L; and Sn4+, 5 mg/L. Orthophosphate precipitates calcium at
the pH of the test. Strontium and barium give a positive interference and alkalinity in excess of
300 mg/L may cause an indistinct end point in hard waters.
Standard Operation Procedure Manual for Analysis of Drinking water quality
Page 60 of 64