What technique measures light blocked as a decrease in light transmitted through a solution?

Turbidimetry is the correct technique for measuring light blocked by particles in a solution as a decrease in transmitted light. This method specifically quantifies the amount of light absorbed or scattered by suspended particles, which results in a reduction of the light that reaches the detector.

In turbidimetry, the focus is on measuring the opacity or cloudiness of a solution caused by those suspended particles. The data obtained are often plotted against concentration to establish a correlation, allowing for the determination of the concentration of the particles based on how much light was diminished.

In contrast, nephelometry measures the scattered light at a particular angle rather than the light transmitted through a solution. Fluorometry involves detecting emitted light from a substance following excitation, which is a different principle entirely. Chromatography is a separation technique, focusing on the separation of compounds based on their interactions with a stationary phase and a mobile phase, rather than measuring light directly.

Therefore, turbidimetry is distinct in its approach to quantifying solute concentration through the measurement of light transmission and is why it is the correct answer to the question posed.