A sample introduction system providing intermittent or discontinuous supply of liquid to a nebulizer is described. In one or more implementations, the sample introduction system includes a nebulizer configured to receive a fluid sample and a nebulizer gas and aerosolize the fluid sample with the nebulizer gas. The sample introduction system also includes a sample pump configured to supply a first aliquot of a sample to the nebulizer during a first time interval, stop supplying the first aliquot of the sample at the end of the first time interval, supply at least substantially no sample to the nebulizer during a second time interval subsequent to the first time interval, and supply a second aliquot of a sample to the nebulizer during a third time interval subsequent to the second time interval.