Quality control laboratory

Chromatographic techniques, particularly gas phase chromatography, are used throughout all areas of the petroleum industry research centers, quality control laboratories and refining units. The applications covered are very diverse and include gas composition, search and analysis of contaminants, monitoring production units, feed and product analysis. We will show but a few examples in this section to give the reader an idea of the potential, and limits, of chromatographic techniques. 

SEMCONDUCTORS - COMPOUND SEMICONDUCTORS] (Vol21) QC. See Quality control laboratories. 

Special, fully automated one-task XPS instruments are beginning to appear and will find their way into both quality control laboratories and process control on production lines before long. 

Many researchers choose to buy expensive GPC/SEC columns from one of the major producers because that producer s columns had been used in the past or because of a successful marketing campaign by one particular producer. It should be noted that repacked columns can be obtained for a fraction of the cost of new columns. American Polymer Standards repacked columns are guaranteed to perform just as well as new columns from any company. When a column is repacked the only parts reused are the stainless-steel tube and end caps. This hardware is then repacked using new frits and new ST-DVB gel. Each column is individually tested in a quality control laboratory and shipped in the customer s choice of solvent. American Polymer Standards offers a column repacking service because it is a practical, inexpensive way for customers to acquire state of the art GPC/SEC columns. 

A quality control laboratory had a certain model of HPLC in operation. One of the products that was routinely run on the instrument contained two compounds, A and B, that were quantitated in one run at the same detector wavelength setting. At an injection volume of 20 /tL, both compounds showed linear response. The relatively low absorption for compound B resulted in an uncertainty that was just tolerable, but an improvement was sought. 

The company was a private label manufacturer of home maintenance and personal care products. Its laboratory would be involved with new product development, evaluation of raw materials, testing of competitive products, and quality control. Laboratory personnel would also be responsible for chemical safety in the plant and for proper waste disposal. 

Table 10.3 Performance of quality control laboratories, four-year average, 1994-97... 

In general, the laboratory in a plant is mainly a quality control laboratory. It will consist of all the off-line equipment necessary to determine whether the product and raw materials meet the desired specifications, and whether all the waste streams meet the criteria set by local, federal, and state authorities. 

Quality control laboratories are a necessary part of any plant, and must be included in all cost estimates. Adequate space must be provided in them for performing all tests, and for cleaning and storing laboratory sampling and testing containers. 

US Environmental Protection Agency Analytical Quality Control Laboratory, US Government Printing Office, Washington DC (1972)... 

SACHEM Inc. of Cleburne, Texas, manufactures various concentrations of tetramethylammo-nium hydroxide (TMAH) solutions to meet customer specifications. To ensure consistent performance, electronic industry requires very narrow concentration specifications for the solutions. In SACHEM s quality control laboratory, standardized acids such as HC1 or H2S04 are used as titrants for the TMAH solutions to check their concentrations. The performance of the assay titration is controlled by daily analysis of internal reference standards (IRSs). If the IRS results are within controlled limits, then the assay results of a product can be reported. If not, the results cannot be reported until the root cause is uncovered and eliminated. Safety glasses and gloves are worn while performing this work in the laboratory. 

The analysis of tetramethylammonium hydroxide (TMAH) solutions manufactured by SACHEM Inc. of Cleburne, Texas, includes the determination of trace elements. These elements cause less-than-optimum performance of integrated circuit boards manufactured by SACHEM s customers that use these solutions in their processes. Alkali and alkaline earth metals (e.g., Li, Na, K, Mg, Ca, and Ba) can reduce the oxide breakdown voltage of the devices. In addition, transition and heavy metal elements (e.g., Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Au, and Pb) can produce higher dark current. Doping elements (e.g., B, Al, Si, P, As, and Sn) can alter the operating characteristics of the devices. In SACHEM s quality control laboratory, ICP coupled to mass spectrometry is used to simultaneously analyze multiple trace elements in one sample in just 1 to 4 min. This ICP-MS instrument is a state-of-the-art instrument that can provide high throughput and low detection Emits at the parts per thousand level. Trace elemental determination at the parts per thousand level must be performed in a clean room so that trace elemental contamination from airborne particles can be minimized. 

SACHEM Inc., located in Cleburne, Texas, is a producer of high-purity bulk chemicals for companies that have high-purity requirements in their chemical processing. As stated in Workplace Scene 1.2, one of their products is tetramethylammonium hydroxide (TMAH), which is sold to semiconductor industries. The analysis of TMAH for trace anions such as chloride, nitrate, nitrite, and carbonate is critical for SACHEM s quality control laboratory. If these ions are present on the integrated circuit boards manufactured by one of their semiconductor customers, they may cause corrosion severe enough to affect the functionality and performance of the electronic devices in which the circuit boards are used. In SACHEM s quality control laboratory, ion chromatography procedures have been developed to measure the anion concentrations in TMAH. Because the concentration levels are trace levels, a clean room environment, like that described in Workplace Scene 1.2, is used. A special procedure for carbonate analysis is required so that the absorption of carbon dioxide from the atmosphere can be minimized. 

On arrival, he found that his duties were not limited solely to modernization of the Hawkesbury laboratory. He was also charged with supervision of the pulp quality control laboratories scattered in a dozen paper mills throughout Canada. 

Reference and research methods. These are generally more sophisticated procedures that are used by central quality control laboratories or by government agencies with qualified personnel. These methods are often used to verify results obtained by the rapid methods described below or to calibrate the instruments. They may also be used to verify additives declared on the label of a food product or to check for the use of non-permitted additives. This aspect is of increasing importance since legislation may vaiy between different countries, and food products are frequently subject to inter-market exports . The most important characteristics of these analytical procedures are ... 

A wide variety of viscometers suitable for liquids are currently available, often with computer control. Many quality control laboratories use simple, cheap, robust instrumentation, which performs quite adequately in a day to day context. However these instruments can have a very narrow range and do not always give well-defined shear rates. This makes them less suitable for research and development work and we will not consider them further here. Figure 3.3 shows schematically the two main instrument types in common use controlled stress, where the stress is applied electrically via a motor leaving us to measure the strain and... 

Elaborate with specific examples the various sampling procedures and errors commonly encountered in a quality control laboratory. 

Another RP-HPLC technique has been applied for the determination of synthetic food dyes in soft drinks with a minimal clean-up. Separation of dyes was obtained in an ODS column (150 x 4 mm i.d. particle size 5 pm). Solvents A and B were methanol and 40 mM aqueous ammonium acetate (pH = 5), respectively. Gradient conditions were 0-3 min, 10 per cent A 3-5 min, to 25 per cent A 5-8 min, 25 per cent A 8-18 min, to 75 per cent A 18-20 min, 75 per cent A. The flow rate was 1 ml/min and dyes were detected at 414 nm. The separation of synthetic dyes achieved by the method is shown in Fig. 3.35. The concentrations of dyes found in commercial samples are compiled in Table 3.21. The quantification limit depended markedly on the type of dye, being the highest for E-104 (4.0 mg/1) and the lowest for E-102 and E-110 (1.0 mg/1). The detection limit ranged from 0.3 mg/1 (E-102 and E-110) to 1.0 mg/ml (E-104 and E-124). It was suggested that the method can be applied for the screening of food colourants in quality control laboratories [113]. 

Eollowing finalization of drug substance synthetic routes and drug product formulation, the focus shifts to the development of robust and transferable methods for post-approval support at quality control units. It is important to remember during the final stage of method development that achievement of separation conditions is only one of the necessary parameters for successful method implementation. Extensive studies to measure robustness and quantitative method performance are conducted to assure that the method performs as intended in quality control laboratories. It should be emphasized that successful method development requires extensive cooperation between the development laboratory and the receiving quality control laboratories. 

FDA Guide to Inspections of Microbiological Quality Control Laboratories, Rockville, MD, July 1993. 

Major categories of process Raman applications include reaction monitoring, in-process quality checks, and mobile or field point measurements. Quality control laboratory applications often are converted to a continuous process monitoring approach, or could simply be viewed as part of a larger production process. 

Natural products, from plants and foods to rocks and minerals, are complicated systems, but their analysis by Raman spectroscopy is a growing area. Most examples come from quality control laboratories, motivated to replace current time-consuming sample preparation and analysis steps with a less labor-intensive, faster technique but most authors anticipated the eventual application to process control. Often a method will be practiced in a trading house or customs facility to distinguish between items perceived to be of different qualities, and thus prices. 

W. Plugge and C. Van Der Vlies, The use of near infrared spectroscopy in the quality control laboratory of the pharmaceutical industry, J. Pharm. Biomed. Anal, 10(11-12), 797-803 (1992). 

Automation needs vary from laboratory to laboratory. Quality control laboratories might emphasize user simplicity and high throughput, while research laboratories might stress flexibility. 

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