S. Korean researchers develop automated dilution device with 99.7% accuracy in 30 seconds

South Korean researchers have developed a new technology that can dilute samples in just 30 seconds.

A research team led by Park Jung-heon, a scientist at the Geoscience and Mineral Resources Analysis Center of the Korea Institute of Geoscience and Mineral Resources (KIGAM), announced Thursday it had developed an "automated mass-ratio dilution device" that fully automates the sample pretreatment process — from dispensing (dividing samples into measured portions) and mass measurement to diluent injection and dilution ratio calculation.

Reliability tests by the research team showed a dilution ratio accuracy of 99.7%. The dilution ratio variation rate was just 0.321%, the variation rate for sample mass measurements was 0.310%, and the variation rate for total mass — combining sample and diluent — was 0.083%. Those figures represent a significant reduction in the operator-to-operator variability that can arise during manual processing.

Dilution is an essential step before injecting samples into analytical equipment, as it lowers concentration to a consistent level for accurate compositional analysis. Conventional methods have relied primarily on volume-based dilution. Volume, however, can be affected by temperature, pressure, humidity and solution density, creating a high risk of error during the dilution process.

The new device automatically calculates and corrects the actual dilution ratio by measuring the mass of the sample and the total mass after diluent is added. Because it uses mass rather than volume as the basis for dilution, it minimizes the influence of environmental conditions and solution characteristics, and ensures samples are processed to the same standard regardless of which operator handles them.

Repetitive tasks — including sample transfer, diluent injection, data recording and dilution ratio calculation — are automated, reducing the likelihood of human error. Direct contact between researchers and samples is also minimized, lowering the risk of contamination and improving the reliability of analytical data.

The device can hold up to 60 15-milliliter centrifuge tubes or up to 24 50-milliliter centrifuge tubes at a time. It can also automatically inject up to five types of reference materials used for calibrating analytical values.

The device handles sample volumes from under 50 microliters to 1,000 microliters, and automatically detects the liquid level in each sample container. The dilution factor can be set anywhere from five to 100 times, and diluent volumes of 100 microliters to 50 milliliters can be injected.

Mass is measured with a precision of 0.1 milligrams. Diluting a single sample takes approximately 30 to 35 seconds. The research team also confirmed the device's stability and durability through repeated tests processing up to 60 samples at a time.

The device is expected to be used first in the analysis of geoscience and environmental samples such as water quality, soil, rock and minerals. It is also anticipated to find applications in advanced industries — including semiconductors, displays, secondary batteries and high-purity materials — where trace components must be managed with precision.

The development is significant because it standardizes and automates not only the performance of the analytical equipment itself, but also the sample pretreatment stage that precedes analysis. Reducing repetitive manual work lowers the risk of cross-contamination and operator-dependent variability, improving analytical accuracy, data reproducibility and research productivity.

"The core achievement of this device is that it standardizes and automates the manual dilution process that has long been repeated in analytical settings, minimizing variability caused by individual operators," Park said. "Going forward, we will expand its range of applications to meet the demand for ultra-precise analysis in advanced industries such as semiconductors and secondary batteries."