December 20, 2019
The purpose of this article is to describe a new cleaning procedure for thoroughly cleaning WPI flowcells, including Liquid Waveguide Capillary Cells (LWCCs), UltraPath flowcells and optical cuvettes.
The image (right) shows a 3000 series LWCC with a MiniStar pump and the LWCC injection system placed on top of it.
Preparation of Chemicals
All chemical reagents should be of at least ACS-Grade, preferably HPLC-Grade. This procedure involves the use of caustic and flammable reagents. Consult the manufacturer’s MSDS for necessary safety precautions.
Cleaning Solution #1:
0.5M Potassium Hydroxide in 100% Ethanol (e.g.: 7 g KOH in 250mL EtOH). After thoroughly mixing, filter the solution through a 20µm pore size filter.
Cleaning Solution #2:
100% Methanol, HPLC grade
Cleaning Solution #3:
Ultrapure water, Type I per ASTM D1193-99 or equivalent
NOTE: Grade 1 ultrapure water per ISO 3696 differs significantly from the above classification.
The preferred method of cleaning involves the use of a spectrometer (e.g. Tidas E Base) or photometer based detection system in “monitor mode” throughout the entire cleaning process. This allows the technician to observe the extent of performance improvement as a function of time.
The image (right) shows the top view of a MiniStar pump and an LWCC Injection System. The injection system has the DIW and Waste containers at the back, and the three cleaning solutions and a sample bottle on the right side.
The simplest cleaning method involves using a peristaltic pump (#MiniStar) to flow each cleaning solution through the sample cell in the appropriate order. A convenient way to perform this task is to use WPI’s LWCC Injection System (#89372). It is recommended that the pump be configured to “pull” through the cell to avoid possib