Application Note
Note
Application
Measuring Organic Pigmentswith the HL Cell
AN256

MEASURING ORGANIC PIGMENTS
WITH THE LA-960V2 HIGH-CONCENTRATION
LOW-VISCOSITY (HL) CELL LY-9609

Introduction
Dyes and pigments are a common additive in nearly
every product on the market today – from clothing andaccessories to food and beverages to household items orcosmetics.
Understanding the particle size distribution for pigments,
inks, and dyes is important for manufacturers, as theparticle size will determine how well a color will covera surface (hiding power), how the finish will look (glossstrength), or even how well the material can absorb light(tinctorial strength).
The High-concentration Low-viscosity Cell (HL Cell) is anaccessory for the LA-960V2 laser diffraction particle size
analyzer. The HL Cell aids in measuring samples of lowviscosity or high concentration. Since liquid inks, dyes,
and pigments are often high concentration, the HL Cell is a
useful accessory for measuring them.

Analytical Test Method
Three organic pigments dispersed in RO water wereanalyzed with the LA-960V2 laser diffraction particle size
analyzer: Violet, Red, and Yellow.
Set the following conditions:
Basic Measurement Conditions• Sample Information:o Sample Name:o Material: Organic Pigment
o Source: (name of vendor)o Lot Number: (found on bottle)o Refractive Index values can be quite high, with realvalues starting from about 2 and going beyond 3.
Imaginary refractive index (related to absorption)
values can range from 0.5 to 5i.
o Form of Distribution: Manualo Iteration Number: 15
o Distribution Base: Volume

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Figure 1. The HL Cell for the LA-960V2 analyzer.

Advanced Measurement Conditions• Measurement tabo Data acquisition times (Sample): 5000
o Data acquisition times (Blank): 5000
o Alignment before measurement: Yes
Test Procedure:
1. Clean the HL Cell glass plates.
2. Place the cell plates into the cell frame with a 5 µm		 spacer between them. Screw the frame together		 tightly to secure.
3. Inject the HL Cell with deionized water using a syringe.
4. Insert rubber cell caps into each hole of the cell glass.
5. Place assembled cell into cell holder and slide tray		 into the measurement position within the LA-960V2.
6. Align the laser and verify that the cell is clean by		 inspecting the channel baseline for any channels		 reading above 500.
7. Take the system Blank.
8. Remove the HL Cell from the cell holder.
9. Clean, dry, and reassemble the HL Cell.
10. When running ink samples such as these, dilution by		 10 to 100x is most often the best.
11. Inject the HL Cell with the diluted pigment.
12. Insert the cell caps and place the cell back into the		 holder within the LA-960V2.
13. Perform alignment of laser.
14. Take 3 measurements.
15. Remove the HL cell and clean it before the next		 measurement.

Results

Violet Pigment

Yellow Pigment

Conclusion
The measurement results shown above prove
the LA-960V2, with the additional functionalityof the HL Cell, make laser diffraction a preferred
method for measuring high-concentration, lowviscosity samples such as pigments.

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Red Pigment