The HI4104 is a liquid membrane, combination ion selective electrode (ISE) for the determination of calcium (Ca2+) in solution. The PVC membrane comprised with organic ion exchanger produces a potential change due to the calcium ion exchange between the organic polymer membrane and the sample. The internal sensing elements are housed within a durable polyetherimide (PEI) body.The HI4104 is ideal for a variety of applications in the food and beverage industry and water analysis.