In some aspects, a device for apportioning granular samples includes a sample feeder defining a conduit, the conduit including a first opening to receive the granular samples and a second opening. The device includes a shuttle operably coupled to the sample feeder to receive the granular samples from the conduit via the second opening. The shuttle is configured to apportion the granular samples to incrementally enter a sample chamber to be analyzed. The device includes an outlet conduit fluidly coupled to the sample chamber and configured to permit the sample chamber to be evacuated.