Elements and compounds can be detected and identified using instrumental methods. These use machines instead of test tubes and human eyes. Instrumental methods are accurate, sensitive and rapid. Sensitive means they can detect very small amounts of a substance, and rapid means the result comes quickly.
Compared with the chemical tests, they are more accurate because a machine does not rely on the observer judging a colour, they can use a very small sample, and they are much quicker.
Flame emission spectroscopy is an example used to analyse metal ions in solutions. The sample is put into a flame and the light given out is passed through a spectroscope. The output is a line spectrum. The positions of the lines are compared with a reference set of spectra to identify the metal ions (for example, lithium has its own set of lines), and the brightness of the lines can be used to measure their concentrations. Unlike a simple flame test, ions in a mixture can each be identified.