Dynamic light scattering (DLS) measurements are often constrained by available sample volume, particularly in early-stage research, high-value formulations, and applications where material conservation is critical. In these cases, the ability to generate reliable particle size data from extremely small sample volumes can improve analytical flexibility while minimizing consumption of precious materials. This technical note describes an experimental procedure for measuring particle size using a minimum sample volume of 1 µL in the Low Volume Disposable Sizing Cell (LVDSC), showing that high-quality size measurements can be achieved when sample handling and alignment are carefully controlled.
Particle characterization workflows often require a balance between measurement quality and sample availability. For nanoscale dispersions and colloidal systems, conventional volume requirements may limit analysis when only small amounts of material are available. The study addressed this challenge using a 61 nm latex dispersion in 10 mM NaCl and compared measurements collected using 10 µL and 1 µL sample volumes in the LVDSC. This is particularly relevant for laboratories seeking low-volume DLS workflows for nanoparticle research, formulation screening, and other applications involving limited sample volumes.
The procedure uses the Low Volume Disposable Sizing Cell (ZSU1002) with the Zetasizer Ultra and is applicable to both the Zetasizer Lab and Zetasizer Ultra platforms. The method relies on introducing the sample into a capillary cuvette, sealing it to prevent separation or bubble formation, and positioning the sample correctly in the center of the viewing holes within the cell holder. In DLS measurements, sample presentation and optical alignment are essential because poor alignment can affect the correlogram and reduce confidence in the final particle size result. The note highlights sample positioning as a critical factor in obtaining robust data quality at very low volumes.
In the study, 1 µL of latex solution was pipetted into the end of a capillary cuvette and sealed with sealing compound, ensuring that no separation of the liquid or bubble formation occurred. The capillary cuvette was then placed into the cell holder so that the middle of the sample aligned directly with the center of the viewing holes. Three repeat size measurements were taken on a Zetasizer Ultra using a 90° detection angle and General Purpose distribution analysis. Measurements were also collected using a 10 µL sample volume in the LVDSC to provide a direct comparison between low- and higher-volume conditions.
The results show that particle size measurements collected from 1 µL were comparable to those obtained from 10 µL. For the 10 µL, 60 nm latex sample, the average Z-average was 67.73 nm with a polydispersity index (PI) of 0.08. For the 1 µL sample, the average Z-average was 66.32 nm with a PI of 0.02. These results demonstrate that a good-quality size measurement can be achieved from as little as 1 µL of sample when the method is executed correctly.
The study also emphasizes the importance of alignment. When the sample is correctly positioned in the center of the viewing hole, a high-quality correlogram is obtained. Slight misalignment results in poorer correlogram quality, reinforcing that precise positioning of the capillary tube is essential for reliable low-volume measurements.
This work demonstrates the practical value of low-volume particle sizing for scientists working with limited, costly, or difficult-to-produce samples. The ability to measure particle size from 1 µL supports workflows involving nanoparticle dispersions, formulation development, and precious research materials where reducing sample consumption is important. For users of the ZSU1002 Low Volume Disposable Sizing Cell with the Zetasizer Lab or Zetasizer Ultra, this approach provides a practical pathway to perform ultra-low-volume DLS analysis while maintaining meaningful data quality.
Register now to access the complete technical note and review the full experimental procedure, measurement setup, repeat measurement data, representative particle size results, and correlogram examples. The full document provides additional practical detail for scientists evaluating whether 1 µL particle sizing is feasible within their workflows and how to optimize sample alignment for high-quality results.
This technical note contains the details of the experimental procedure for size measurements using a minimum sample volume of 1 µL in the Low Volume Disposable Sizing Cell (LVDSC) cell.
To add the sample, 1 µL of the latex solution was pipetted into the end of a capillary cuvette, as shown in Figure 1, and then sealed with the sealing compound, ensuring that no separation between the liquid or bubble formations had occurred.
![[TN260608-figure1.jpg] TN260608-figure1.jpg](https://dam.malvernpanalytical.com/a1d5941d-f6ec-4cdb-8b1e-b4630029d643/TN260608-figure1_Original%20file.jpg)
The capillary cuvette was then placed inside the cell holder with the middle of sample lined up directly in the center of the viewing holes. Three repeat size measurements were taken on a Zetasizer Ultra using a 90° detection angle and the General Purpose distribution analysis.
![[TN260608-figure2.png] TN260608-figure2.png](https://dam.malvernpanalytical.com/a66a5278-2ead-4ff9-941c-b4630029d7a7/TN260608-figure2_Original%20file.png)
Figure 3 presents the particle size measured using 10 µL in an LVDSC, demonstrating results comparable to those obtained with 1 µL of sample in Figure 4.
![[TN260608-figure3.png] TN260608-figure3.png](https://dam.malvernpanalytical.com/21aa9c43-3455-4cf9-9585-b4630031bcf3/TN260608-figure3_Original%20file.png)
![[TN260608-figure4.png] TN260608-figure4.png](https://dam.malvernpanalytical.com/cd385ee5-254b-4093-a6e1-b4630031be3e/TN260608-figure4_Original%20file.png)
Table 1 contains the size and polydispersity index (PI) results from the three repeat size measurements of the 10 µL and 1 µL volumes using the LVDSC.
| 10 µL, 60 nm latex sample | 1 µL, 60 nm latex sample | |||
|---|---|---|---|---|
| Z-average, nm | PI | Z-average, nm | PI | |
| Rep 1 | 67.00 | 0.08 | 66.4 | 0.02 |
| Rep 2 | 68.52 | 0.07 | 66.66 | 0.01 |
| Rep 3 | 67.66 | 0.08 | 65.91 | 0.04 |
| Average | 67.73 | 0.08 | 66.32 | 0.02 |
| STD | 0.76 | 0.008 | 0.38 | 0.02 |
As it can be seen from Table 1, the 10 µL latex sample measured an average of 67.7 nm in comparison to the 1 µL latex sample which measured an average of 66.6 nm. The results show that a good quality size measurement can be achieved from as little as 1 µL of sample. This is further supported by the data quality guidance.
![[TN260608-figure.png] TN260608-figure.png](https://dam.malvernpanalytical.com/06d86ac7-090e-444e-8120-b4630031bc48/TN260608-figure_Original%20file.png)
![[TN260608-figure5.png] TN260608-figure5.png](https://dam.malvernpanalytical.com/053cd2ce-e3ae-4e44-a2a5-b4630031bf4e/TN260608-figure5_Original%20file.png)
![[TN260608-figure6.png] TN260608-figure6.png](https://dam.malvernpanalytical.com/7bc7b88e-b379-41e5-ad47-b4630031bf10/TN260608-figure6_Original%20file.png)
To achieve high quality results the sample must be aligned correctly in the center of the viewing hole, as shown in Figure 5. If the sample is misaligned, the correlogram will look as shown in Figure 6. To remedy this problem the capillary tube must be realigned ensuring the sample is in the correct position.
The results reported in the technical note confirm that a sample volume of 1 µL can be measured for size using a ZSU1002 on a Zetasizer Lab and Ultra.