As the number of viable particles — colony forming units (CFUs) — impact on an agar plate increases, the probability that viable particles will enter unoccupied space decreases. Particles tend to run in straight lines and adhere to surfaces (agar plates) directly in their path. The impactor design allows viable particles, flowing in straight lines, to accelerate through the slits at an optimal flow rate. This results in viable particles captured at a high biological efficiency.
Regulations have lead to a requirement for an automated, remote monitoring solution. But what are the components of this solution, and how are they implemented? The FacilityPro Environmental Monitoring System follows this format: design, build, install, test, and validate.
Transportation of particles through tubing between the sample inlet and the optics of a particle counter has often been at the forefront of discussion regarding the validity of readings. With the release of the 2008 EU GMP Annex 1 (with an updated draft released in December 2017) the issue of particle loss of large particles has been elevated.
Most Optical Particle Counters use a light source to illuminate a sample volume, an optical system to collect the particle’s scattered light pulse, a process to convert the scattered light into an electrical signal, and electronics to correlate particle size with the scattered light pulse. While the specific design varies greatly between manufacturers (and while the instruments vary with different sensitivity and flow rates), the fundamental principles of optical particle counter operation are quite similar across the industry.
When monitoring larger size particles, extinction optical particle counting is the typical method used for accurate results. The refractive index difference between microcontaminants and the liquid media being measured can be explored in an effort to determine the related extinction response. At submicron particle ranges, the index contract between a particle and the liquid media is important. The interplay of refractive index contrast and particle size analysis in liquids can be explored and described with the aid of Mie theory.
The ability to measure the cleanliness of objects of various shapes and materials is important in maintaining a comprehensive contamination control program. This allows a Contamination Control Engineer (CCE) to qualify the effectiveness of different cleaning methods. This can include in-house cleaning lines and comparing parts purchased from various vendors to make direct cleanliness comparisons of different commodity items (gloves, wipes, etc.).
A dedicated, point-of-use monitor offers the following advantages over a conventional multipoint sampling system: continuous monitoring, no missed contamination events, sample tubing lengths reduced from 20 – 30 meters to 2 – 3 meters, and 5 – 10x better sensitivity.
With its 10 nm sensitivity, the NPC10 NanoParticle Counter bridges the gap between conventional aerosol optical particle counting at 0.1 µm (100 nm) and sub-nm scale airborne molecular contamination.
The Ultra DI® 20 was specifically developed to meet the challenges of microelectronics UPW cleanliness monitoring.
Connecting instruments and electronics to power outlets can be challenging—especially in remote locations where an outlet is not easily reached. A technology that is quickly expanding is Power over Ethernet (PoE) because it provides power and network communications through a standard network cable. This application note discusses PoE technology and the applications.