Reference standards dispensing

Reference ASTM 114—00, Standard Test Method for Chemical Analysis of Hydraulic Cement. As suggested in this document, the sample should not be a slag cement sample. Your instructor may choose to dispense... 

De-proteinisation of diluted whole blood, and acid extraction of lead from proteins with 2M HNOs is the preparation chosen for the National Bureau of Standards reference method for blood-lead analysis [28]. Centrifugation of blood samples treated in this way yields clear supernatant fractions that contain all of the lead present, and which are easily dispensed into electrothermal atomisers using auto-sampling techniques. This method gave results that compared very well with those obtained using anodic stripping voltammetry, r = 0.975, for concentrations of 10—900 pg l-1 of lead in blood [15]. 

Figure 4 The 384-channel parallel multidispensing of (a) 1 jiL and (b) 200 nL aliquots out of one aspiration into empty wells. The false color maps on the left show the DFM values of the dispensed aliquots over the plate. The color code for the DFM values is shown in a look up table (vertical bars on the right-hand side of the two plate maps). The histograms show the distribution of the DFM values around the mean (average) aliquot volume. The false color map, the DFM histogram, and the stated values for %Bias, %CV, and min/max %DFM in (a) and (b) refer to one representative plate from the 24 replica plates produced in a replication cycle for (a) 1 pL and (b) 200 nL aliquots, respectively. Roche uses the first 2 columns (2 X 16=32 wells) in each 384-well plate for standards and controls since columns 1 and 2 are not filled with compounds, they are not included in the false color maps...

Although laser ablation usually dispenses with the need for sample preparation in the analysis of rocks, the use of a major element of the sample as internal standard requires the prior knowledge of its concentration also, the addition of an internal standard element to a rock sample is difficult. Fusion of the sample with Li,B407 allows the use of Li and B as internal standards. Linear calibration graphs (constructed from standard reference geological materials) have thus been obtained for Al, Ca, Fe, K, Mg, Na, Si and Ti, and relative standard deviations of 1-2% n = 12) achieved. 

Reference material sets which are certified by the International Confederation for Thermal Analysis and Calorimetry (ICTAC) are available through the US National Institute of Standards and Testing (NIST), and are listed in Appendix 2.2. High-purity metals and organic compounds including polymers have been certified. If the standard reference material must be dispensed with a syringe into the sample vessel (for example cyclohexane), care must be taken to ensure that only one droplet is formed in the sample vessel. Multiple transition peaks will be observed if there is more than one droplet present. The transition temperatures listed in Appendix 2.2 are the statistical mean values of measurements made in a number of laboratories and institutes. The ICTAC reference materials are certified for temperature calibration only and not for enthalpy calibration. The reference temperatures in Appendix 2.1 should be used if very accurate calibration of the instrument is required. In order to determine the heat capacity Cp ) of a sample, sapphire (a-alumina, AI2 O3) is used as a standard reference material. The Cp of... 

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