Equipment cleaning rinse sampling

Samples of the vessel rinses are collected in 500-ml volumetric flasks after final rinsing of the vessels with purified water as described in the individual equipment cleaning SOP. 

Equipment blank is a sample of water collected from the surface of a decontaminated sampling tool to verify the effectiveness of a cleaning procedure. Equipment blanks are sometimes called rinsate blanks. They are collected as samples of the final rinse water from non-disposable sampling tools after they have been cleaned between samples. The field crew pours analyte-free water over the tool s surface that has come in contact with the sampled medium. The water is diverted directly into sample containers and analyzed for the project contaminants of concern. 

In preparation for one trip, Patterson and his colleagues cleaned 500 plastic containers in vats of nitric acid, rinsed them in pure water, filled them with pure argon to displace lead-contaminated air, and sealed them in plastic bags equipped with breath filters. Even then, the containers contributed about 0.05 millionths of a gram of lead to each sample as they were trucked from the factory to Caltech, automobile exhaust had sprayed them with thousands of micrograms of lead. For Patterson s next trip, he collected the containers directly from the factory production line and sealed them immediately into plastic bags before their trip to his laboratory. 

Cleaning is a form of maintenance which is particularly relevant where a piece of equipment is used repeatedly, but is also applicable to decontamination of equipment after use in dirty environments. The purpose of cleaning is to ensure that when the piece of equipment is used for an application or measurement, the risk of contamination from previous samples, chemicals, standards or the laboratory environment will be minimized. In the majority of cases, the process of cleaning introduces new chemicals to whatever is being cleaned. After cleaning, the equipment must be well rinsed to remove all traces of the cleaning chemicals, and then dried. 

At the end of approval cleaning, the equipment should be rinsed with sterile water for injection. The water for hnal rinse shall be tested for its conductivity. As an alternative, run a placebo batch after a production batch and subsequent cleaning. Analyze the samples of placebo batch for the active ingredients of the previous run batch to ensure that there is no cross-contamination. 

Rinse the equipment with acetone after the cleaning. Analyze the rinsing using a UV spectrophotometer (sample size 20 ml). Wipe at each selected location a surface area of between 100 and 800 cm or alternatively rinse the equipment with a suitable liquid and check. 

Archaeological bone samples were treated for diagenesis before sample analysis. The bone samples were first mechanically cleaned with the Patterson NC-350 dental drill equipped with a carbide burr to remove any organic matter or contaminants. The mechanical cleaning also removed the layers of cortical bone most susceptible to diagenetic contamination, as well as all traces of trabecular bone. The bone samples were then chemically cleaned in an ultrasonic bath. The samples were first sonicated in water for 30 minutes, then rinsed and sonicated in 5% acetic acid for 30 minutes, and finally rinsed and sonicated with 5% acetic acid for 5 minutes (30, 53, 55, J9).The bone samples were dried for 1 hour at approximately 80°C. Finally, the bone samples were placed in a crucible and ashed at approximately 800°C for 10 hours. 

Check that the equipment was cleaned properly following previous processing and that acceptable cleanliness was indicated by rinse and/or swab sample results. Ensure that all cleaning agents (e.g., detergents) have been removed from surfaces of the equipment. 

All carbons used in this research were pretreated to remove fines by sonication (Bransonic 220, Branson Cleaning Equipment) for 30 seconds followed by a rinse with Type I reagent-grade water (Millipore Corp). Coal-based carbons were then extracted with 2-N HCl in a soxhlet extractor for 42 hours to remove ash components and alkaline impurities. After extraction, the sample was boiled for four hours, then exhaustively rinsed until the pH of the suspension was in the range 5 to 6. All carbon samples were dried at 100 °C under vacuum, and stored in a vacuum desiccator. 

As part of the validation of the cleaning method, the cleaned surface is sampled for the presence of residues. Sampling should be made by an appropriate method, selected on the basis of factors such as equipment and solubility of residues. For example, representative swabbing of surfaces is often used, especially in areas that are hard to clean or where the residue is relatively insoluble. Analysis of rinse solutions for residues has also been shown to be of value where the residue is soluble or difficult to access for direct swabbing. Both methods are useful when there is a direct measurement of the residual substance. However, it is unacceptable to test rinse solutions (such as purified water) for conformance to the purity specifications for those solutions instead of testing directly for the presence of possible residues. 

The cleaning validation protocol should describe the equipment to be cleaned, methods, materials, and extent of deaning, parameters to be monitored and controlled, and analytical methods. The protocol should also indicate the type of samples (rinse, swabs) to be obtained, and how they are collected, labeled, and transported to the analyzing laboratory. 

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