The daily routine in analytical labs can be demanding. Manual workflows often require constant operator attention, leaving room for errors and inconsistencies. Automating density measurements with the D5 Excellence Density Meter and the InMotion PX One Autosampler not only saves time but also improves repeatability and reproducibility.
To demonstrate these benefits, METTLER TOLEDO conducted a comparative study using fruit juice samples. The results highlight how automation leads to greater consistency, efficiency, and independence from operator variability.
Figure 1. InMotion PX One connected to the Excellence Density Meter D5.
Eight different fruit juice samples were prepared in bulk and divided into six batches each. Three operators measured density in two ways:
For each juice type and method, five density determinations were performed. The density values were then converted into Brix results, providing a direct measure of sugar content. Control measurements were carried out on deionized water and air at the start and end of each day. In total, 52 complete density determinations were performed under normal lab conditions.
Figure 2. All Excellence Density Meters can be connected to an InMotion PX Autosampler. The autosampler allows up to 3 rinse solvents to be set up for a proper cleaning depending on the samples.
The study compared the mean values across five replicates per juice sample, highlighting differences in reproducibility between manual and automated methods.
Sample preparation required around 30 minutes, while automated analysis took only 4.5 minutes per sample. Manual measurements required approximately 10 minutes per sample.
The difference between methods became especially clear in the juice samples:
This demonstrates that automation removes much of the operator-dependent variability that can compromise data quality.
Figure 3. Comparison of natural orange juice Brix results within and between the sample series.
Table 1. Comparison of the results between sample series. The left three columns show the comparison between the operators when using the automated system. The right columns show the comparison of the results between the operators doing manual measurements.
Table 2. Comparison of the results within sample series. All operators measured the air and water samples very accurately but did not achieve the same repeatability with the juice samples.
Automating the D5 Excellence Density Meter with the InMotion PX One Autosampler offers clear advantages:
By streamlining density analysis and eliminating subjective factors, the D5 Excellence Density Meter with InMotion PX One Autosampler helps laboratories achieve reliable, high-quality results, independent of operator skill or workload.
Branislav Pavlovic is Product Manager for Physical Values at METTLER TOLEDO, where he leads the Density and Refractometry portfolio.
With a Master’s degree in Chemistry from ZHAW Wädenswil and extensive experience in analytical chemistry and laboratory management, Branislav brings a strong technical background and practical insight.
