Quality control of data

ISO, IUPAC and AOAC INTERNATIONAL have co-operated to produce agreed protocols on the Design, Conduct and Interpretation of Collaborative Studies 14 and on the Proficiency Testing of [Chemical] Analytical Laboratories .11 The Working Group that produced these protocols has prepared a further protocol on the internal quality control of data produced in analytical laboratories. The document was finalised in 1994 and published in 1995 as the Harmonised Guidelines For Internal Quality Control In Analytical Chemistry Laboratories .12 The use of the procedures outlined in the Protocol should aid compliance with the accreditation requirements specified above. 

Modelling of solar radiation components (diffuse and direct) in clear sky conditions is necessary in many solar energy applications (systems design and simulation, radiometers accuracy control procedures, quality control of data, recovering of observational missing data, etc) as well as in routine procedures in engineering. 

We focus on the combination of transcriptomics and metabolomics and more specifically on microarray data, which is currently the most used method for gene expression profiling and is used on a routine basis. In the first paragraphs, we briefly revise the extraction of mRNA or metabolites, their measurement, quality control of data, and analysis methods. Afterward two different types of data fusion and recent tools and publications are reviewed, followed by visualization methods for obtained data. Lastly, the metabolite annotation Web server MassTRIX is presented. This Web server allows combined analysis of transcriptomic and metabolomic data in the context of metabolic pathways. We compared the metabolomics part against similar tools and give a short outlook on the next version of MassTRIX, MassTRIX 4. 

The quality control of galvanic anodes is reduced mainly to the analytical control of the chemical composition of the alloy, to the quality and coating of the support, to an adequate joint between support and anode material, as well as to restricting the weight and size of the anode. The standards in Refs. 6, 7, 22, 27, 31 refer to magnesium and zinc anodes. Corresponding specifications for aluminum anodes do not exist. In addition, the lowest values of the rest potentials are also given [16]. The analytical data represent the minimum requirements, which are usually exceeded. 

Ihnat M (1998b) Plant and related reference materials for data quality control of elemental content. In Kalra YP (ed.) Handbook of Reference Methods for Plant Analysis pp 235-284. CRC Press, Boca Raton. 

Chemical analysis finds important applications in the quality control of industrial processes. In an ideal situation a continuous analysis of the process stream is made and some aspects of this are discussed in Chapter 12. However, such continuous analysis is by no means always possible, and it is common to find a process being monitored by the analysis of separate samples taken at regular intervals. The analytical data thus obtained need to be capable of quick and simple interpretation, so that rapid warning is available if a process is going out of control and effective corrective action can be taken. 

Several algorithms are available for the analysis of MS/MS spectra including SEQUEST, MASCOT, and X Tandem among others. Note that additional secondary quality control of assessment of MS/MS data has recently been implemented to assess identification probabilities and false positivity rates. The MS/MS spectra from an experiment can be interrogated against a concatenated forward and reverse database and an assessment of the intrinsic error rate of the data set can be made. Other approaches for secondary analysis of matching scores for peptide sequencing data include XCorr score normalization routines that are independent of peptide and database size.33... 

While reported data on the acute and chronic toxicity of many pesticides is plentiful, few studies have been published on toxicity bioassays applied to wastewaters containing pesticides. The application of toxicity bioassays to the quality control of wastewaters offers several advantages in addition to being a... 

Model-independent techniques compare data pairs observed at corresponding time values, where time is only a class effect, as in a paired -test or in an ANOVA. A data-poor set of only two or three observations, originating from routine quality control of an immediate-release dosage form, cannot be treated other than model independent. 

A simple TLC method has been developed for the separation and identification of flavons and flavon glycosides in the extract of Phillyrea latifolia L. The leaves (100 g) were defatted in 11 of chloroform for 24 h and then extracted with 2 X 11 of ethanol-water (80 20, v/v). The collected extracts were concentrated and extracted again with n-hexane to remove chlorophylls and other apolar constituents. Analytes were extracted with ethyl acetate. Both normal phase and RP-TLC have been used for the separation of flavonoids. The results are compiled in Table 2.36. It was concluded from the data that TLC can be successfully applied for the quality control of plant extracts containing various flavone derivatives [124],... 

During a recent expedition in the Indian Ocean, as part of the WOCE Hydro-graphic Program, members of the U.S. DOE C02 Survey Science Team used these reference materials extensively for the quality control of measurements of total DIC and total alkalinity. Two manuscripts detailing the results of these measurements on reference materials were published describing the C02 measurements made on that expedition and how reference materials were used to assess the overall data quality (Johnson et al., 1998 Millero et al., 1998). 

Briefly, to assure quality assurance and quality control, samples are analyzed using standard analytical procedures. A continuing program of analytical laboratory quality control verifies data quality and involves participation in interlaboratory crosschecks, and replicate sampling and analysis. When applicable, it is advisable, even insisted upon by the EPA, that analytical labs be certified to complete the analysis requested. However, in many cases, time constraints often do not allow for sufficient method validation. Many researchers have experienced the consequences of invalid methods and realized that the amount of time and resources required to solve problems discovered later exceeds what would have been expended initially if the validation studies had been performed properly. 

Chen JJ et al (2007) Reproducibility of microarray data a fiu-ther analysis of microarray quality control (MAQC) data. BMC Bioinformatics 8 412. doi 1471-2105-8-412 (pii) 10.1186/1471-2105-8-412... 

With commercially available automatic sampling devices, large numbers of samples can be routinely analyzed by LC without operator intervention. Such equipment is popular for the analysis of routine samples (e.g., quality control of drugs), particularly when coupled with automatic data-handling systems. Automatic injectors are indispensable in unattended searching (e.g., overnight) for chromatographic parameters such as solvent selectivity, flow rate, and temperature optimization. 

Quality control of fragrance and flavor substances as well as the products derived from them, comprises the comparison of sensory, analytical and if necessary, microbiological data with standards and specifications. To a large extent these have been established in official specification collections (Pharmacopoeias, ISO, AFNOR, Essential Oil Association). 

Water samples (drinking water, rain, sea, river or waste water and others) have been characterized by ICP-MS with multi-element capability in respect to metal impurities (such as Ag, Al, As, Ba, Be, Ca, Cd, Cr, Co, Cu, Fe, Hg, K, Na, Sb, Se, Mg, Mn, Mo, Ni, Pb, Tl, Th, U, V and Zn) in many laboratories in routine mode with detection limits at the low ng I 1 range using ICP-QMS, and below by means of ICP-SFMS. Drinking water samples are controlled in respect of the European legislation (Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption). For quality control of analytical data, certified standard reference materials e.g. drinking water standard (40CFR 141.51), river water reference material SLRS-4 or CASS-2 certified reference sea-water material and others are employed. 

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