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Mass standardisation

B. Standardisation against sodium tetraborate. The advantages of sodium tetraborate decahydrate (borax) are (i) it has a large relative molecular mass, 381.44 (that of anhydrous sodium carbonate is 106.00) (ii) it is easily and economically purified by recrystallisation (iii) heating to constant weight is not required (iv) it is practically non-hygroscopic and (v) a sharp end point can be obtained with methyl red at room temperatures, since this indicator is not affected by the very weak boric acid. [Pg.288]

In semi-dilute solutions, the Rouse theory fails to predict the relaxation time behaviour of the polymeric fluids. This fact is shown in Fig. 11 where the reduced viscosity is plotted against the product (y-AR). For correctly calculated values of A0 a satisfactory standardisation should be obtained independently of the molar mass and concentration of the sample. [Pg.26]

The extent to which fragmentation takes places for each dissociation pathway of the additives depends on the excess of internal energy imparted to the molecular ion. Because the experimental conditions for product-ion mass spectra are strongly instrument dependent, generally not very well standardised and difficult to exchange between instruments from different... [Pg.406]

In a typical MIP-MS instrument, the ICP portion is replaced with one of a variety of microwave discharge sources, usually a fairly standardised (modified) Beenakker cavity connected to a microwave generator. The analytical MIP at intermediate power (<500 W) is a small and quiet plasma source compared with the ICP. The mass spectrometer needs no major modifications for it to be interfaced with the MIP. With MIP used as a spectroscopic radiation source, typically consisting of a capillary (1mm i.d.), a power of 30-50 W and a gas flow below 1 L min 1, multi-element determinations are possible. By applying electrodeposition on graphite electrodes, ultratrace element determinations are within reach, e.g. pg amounts of Hg. [Pg.624]

IS(TD) Internal standardisation (calibration) mLOD Mass limit of detection... [Pg.769]

Association Fran aise de Normalisation French Association for Standardisation (Paris, France) Automated Mass Spectral Deconvolution and Identification System (NIST)... [Pg.771]

For comparison of the different ionisation methods and detection modes, the results obtained as FIA overview spectra are presented in Figs. 2.11.7 and 2.11.8. Reconstructed ion chromatograms (RIC) of APCI and ESI combined with selected mass traces of all LC separations and, in parallel, the selected standardised mass traces of the C42 and C14 homologues containing three ethoxy chain links recorded in the negative mode are presented in Fig. 2.11.9. These results again demonstrate the quite large variation in the ionisation efficiency of... [Pg.343]

Marcomini et al. [42] studied the aerobic biodegradation mechanisms of different commercial AE blends (linear, oxo- and multibranched alkyl chains) by analysing the metabolites under the same standardised conditions applying liquid chromatography mass spectrometry LC-MS. [Pg.481]

Vassort, A., Barrett, D. A., Shaw, P. N., Ferguson, P. D., and Szucs, R. (2005). A generic approach to the impurity profiling of drugs using standardised and independent capillary zone electrophoresis methods coupled to electrospray ionisation mass spectrometry. Electrophoresis 26, 1712—1723. [Pg.306]

Internal standard (IS) calibration requires ratioing of an analytical signal to an IS which has very similar characteristics to that of the analyte of interest (an element which is similar to the analyte either in mass, ionisation potential or chemical behaviour). Quantitative analysis applying internal standardisation is the most popular calibration strategy in ICP-MS, as improvements in precision are obtained when the technique is appropriately used. Of course, the validity of this calibration method requires that one ensures a good selection of the correct internal standard. For this purpose it is possible to resort to chemometric methods [16]. [Pg.26]

The contribution of flow analysis to improving the performance of atomic spectrometry is especially interesting in the field of standardisation. FIA can provide a faster and reliable method to relate the absorbance, emission or counts (at a specific mass number) to the concentration of the elements to be determined. In fact, flow analysis presents specific advantages to solving problems related to the sometimes short dynamic concentration ranges in atomic absorption spectrometry, by means of on-line dilution. The coupling of FI techniques to atomic spectrometric detectors also offers tremendous possibilities to carry out standard additions or internal standardisation. [Pg.36]

The widespread use of chromatography in quantitative analysis is mainly due to its reliability and to its use in standardised analyses. This type of analysis relies mainly on reproducibility of the separation and on the linear relationship that exists between the injected mass of the compound and the area of the peak in the chromatogram. The use of an integrating recorder or a microcomputer with the appropriate data treatment software allows automation of all the calculations associated with the analysis. Computer software can analyse the results and produce a computerised report. Trace and ultratrace analyses by chromatography are often the only recognised methods (EPA Methods for Environmental Analyses), although their costs are relatively high. The three most widely used methods are described below in their simplest formats. [Pg.74]

Standardising the reactant following the question, 1 ml of this solvent has a water content of 3/15 ml of KF reagent. In oxalic acid dihydrate (M = 126g/mol), the mass concentration of water is 36/126 = 28.57%. The information given permits the following calculation to find the titre of the reactant ... [Pg.431]

The Delta Mooney (A Mooney) test is an extension of the Mooney used on empirical grounds as a general indication of processibility for non-pigmented oil extended emulsion styrene/butadiene rubber. It quantifies the changes that occur in Mooney viscosity with time, either as the difference between viscosities recorded at two specified times or as the difference between the minimum viscosity recorded immediately after the commencement of the test and the subsequent maximum viscosity. Several alternative Delta Mooney values are defined depending on the times, whether minimum/maximum viscosity difference is used and whether or not the sample has been massed on a mill. Procedures for Delta Mooney are standardised in ISO 289-341, BS 903 Part A58-142 and in ASTM D334643. [Pg.74]

Although not standardised for use with rubbers, the method of determination of gravimetric thickness is used for thin plastic film and could have use with rubber film or coatings. In the method of ISO 459111 a square test piece of 100 cm2 area is weighed in air and water to give mass and density and from this the average or gravimetric thickness can be calculated. [Pg.102]

It may be of interest to know the amount of matter which a liquid extracts from the rubber. Despite the fact that neither is very accurate, two procedures are given in the standard drying the treated rubber to find loss in mass from the original, or drying off the test liquid and weighing any residue. It is difficult to see the value of attempting to standardise this sort of procedure, as it is unlikely to be used in specifications. [Pg.322]

Standardisation is also sometimes employed, but must be done before unfolding for meaningful results an example might be in the GC-MS of a series of samples, each mass being of different absolute intensity. A sensible strategy might be as follows ... [Pg.309]

Perform PCA on the dataset, but standardise the intensities at each mass, and retain two PCs. Present the scores plot of PC2 versus PCI, labelling all the points in time, starting from 1 the lowest to 25 the highest. Produce a similar loadings plot, also labelling the points and comment on the correspondence between these graphs. [Pg.401]

Perform PCA, standardised, again on the reduced 25 x 10 dataset consisting of die best 10 masses according to the criterion of question 4, and present the labelled scores and loadings plots. Comment. Can you assign m /z values to the components in die mixture ... [Pg.401]

Both variolin B and its 5-deoxy derivative 19 (Scheme 6.1 Part 2) have shown promise in pharmacokinetic and in vivo studies. These compounds have been shown to have long terminal half-lives and low normal cell toxicity, however the 5-deoxy derivative demonstrated better Cmax, plasma clearance and terminal plasma half-life.318,319 Both are effective against human lung carcinoma cell lines in nude mice.104 The deoxy-variolin B showed growth inhibitory activity against human leukemic cell lines.105 A standardised method for liquid chromatography-mass spectrometry (LC-MS)/MS analysis of plasma has been developed to monitor the results of the in vivo studies.320... [Pg.186]


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Standardisation

Standardise

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