Reduced osmolarity ORS does not contain which of the following ion?

Low osmolarity ORS Sodium - 75 mmol/L Potassium - 20 mmol/L Chloride - 65 mmol/LCitrate - 10 mmol/LGlucose - 75 mmol/L (Refer: OP Ghai's Textbook of Pediatrics, 8th edition, pg no. 263)