gravimetric method

https://doi.org/10.1351/goldbook.G02694
A determination by weight; e.g. in the older method of Cl ion determination, a weighed amount of sample is dissolved in water, AgNO3 solution added, AgCl is precipitated, dried and weighed. From the known mass fraction of silver in AgCl, the weights of the initial sample and that of the AgCl precipitated, the percentage of chlorine in the sample can be calculated readily.
Source:
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2192 (https://doi.org/10.1351/pac199062112167)