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Product Number: 2657512
Phenol Red Indicator Solution in a 100 mL marked dropper bottle provides an easy-to-use colorimetric method for determining pH. It changes from yellow to red as the sample becomes more alkaline, providing a simple and reliable way to measure pH using a colorimeter.
This phenol red indicator solution is used in Method 10076, which is designed to determine the pH of neutral and slightly alkaline waters in the range of 6.5 to 8.5 units. Chlorine does not interfere at levels of 6 mg/L Cl2 or less, but salt water (seawater) interferes and cannot be analyzed with this method. A colorless pH 7 buffer (PN 1222249) is used as a control standard in this method, with results expected to be within +/-0.1 pH unit.
Chlorine greater than 6 mg/L may interfere with this phenol red pH test. To remove chlorine from the sample, add one drop of 0.1 N sodium thiosulfate solution (PN 2700832) per 5 mL sample, mix, and then add the pH indicator. This procedure will remove up to 50 mg/L of chlorine from the sample. A DR900 or DR300 colorimeter is required for this method.
Phenol Red (PN 2657512) is a component of these items: 251242, 2688800, and 2691100. Method 10076 requires a colorimeter such as the DR900 or DR300.
