Labelling, reference values

Reference intakes depend on age and gender. For nutritional labelling of foods it is obviously essential to have a single labelling reference value that will permit the consumer to compare the nutrient yields of different foods. Apart from foods aimed at infants and small children, for which age-related reference intakes are used, there are two ways of determining labelling reference values ... 

Figure 11.1. A flow-model scheme for treating the protein routing question. Labels refer to flow rates of carbon. The total carbon flux, into and out of the body, is 1, divided into F (for protein) and 1 - F for the remainder. The significant relevant internal fluxes are between the amino acid pool (coupled to the body protein pool), and the energy metabolism pool . The extent to which protein routing is observable in the body protein composition depends on the value ofX (See Fig. 11.2). Numbers in refer to suggested isotopic fractionations associated with a metabolic path, which are consistent with the data of the Ambrose and Norr (1993) and Tieszen and Fagre (1993) data set (see Section 4.1).

The parameters of the display are established in GRAFINIT, and the number of variables to watch is specified by numplot. There must be a corresponding number of reference values in the plotz array, sensitivity values in the plots array, and labels in the plotl array. As a convenient start, I set plotz equal to the initial values and plots equal to the initial... 

The United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS) includes an internationally standardized guidance procedure on Transformation/Dissolution Protocol (T/DP) for metals and sparingly soluble metal compounds (United Nations, 2007), recently validated by the OECD (Organization for Economic Cooperation and Development). To establish the acute aquatic hazard classification level of a metal-bearing substance under the GHS, data from the T/DP are compared with an acute ecotoxicity reference value (ERV) derived under conditions similar to those of the T/DP. 

Reference values of this approach are not different from those for other amino acid analyses. An example of a mass chromatogram, representing the plasma of a PKU patient, is shown in Fig. 2.1.1. When evaluating the results of MS/MS amino acid analyses, one has to reahze that the hquid chromatographic separation is by far less efficient that the AAA separation. For this reason, any amino acid may (partly) coelute with other amino acid(s), which potentially interferes with its mass spectromet-ric behavior. This effect is known as quenching. In order to overcome this as much as possible, stable-isotope-labeled internal standards (as many as possible) should be used. However, this matrix effect of ion suppression is the major pitfall in the MS/MS analysis of amino acids. Consequently, the MS/MS analysis of amino acids cannot be regarded as a reference method, similar to all other amino acid analytical methods. 

Use the reference method (e.g., unitai. t or unii aij) to determine the moisture content of each reference sample. Label each corresponding NMR reference sample from the split lot with the values to be used as reference values. 

United States regulations on nutrition labeling of foods require that cholesterol content be given and that it be analyzed by GC measurement as shown in the AOAC method, which uses a packed column (Lewis et al., 1996 AOAC, 1990). The reference value, which is a set of recommended nutrient intake levels of cholesterol, is defined as 300 mg. However, the Codex guideline does not request labeling of cholesterol. Cholesterol contents in some foods and foodstuffs determined by GC measurement are summarized in Table Dl.3.3. 

DRV Daily Reference Values U.S., 1990 Reference values for fat, carbohydrate, sodium, potassium, and protein for labeling purposes... 

The Nutrition Labeling and Education Act defines a Daily Reference Value for sodium to be listed in the Nutrition Facts portion of a food label. 

Fig. 11.19. The fractional change in transfer integrals of eight-ring para-phenylene oligomers from the uniform value, t, in the interacting limit. The parameters used in the Pariser-Parr-Pople-Peierls model (eqn (7.1)) are U = 10.06 eV, t = 2.514 eV, and A = 0.12. The labels refer to the bonds shown in Fig. 11.16. Only the upper rung of bonds are shown.

The LC-IDMS method is an excellent approach for establishing reference values and can be useful in investigating and validating methods. An iso-topically labelled version of thiamine used in the study performed by... 

Reference values for the acylcarnitines are derived from >500 patients, mostly pediatric (0.2-16 yrs), evaluated for metabolic disorders in the author s laboratory but with no manifest biochemical evidence of disease. Individuals with any markedly abnormal values were discounted. The analytical method used was tandem mass spectrometry with electrospray ionization. Internal standards used were stable isotope-labeled analogs of acetyl, propionyl, butyryl, octanoyl and palmitoyl carnitine. The values for straight-chain C2, C3, C4, C5, C6, C8, CIO, C14, C16 and Cl8 1 species are in pmol/1 and are derived from calibration curves using analytical standards all other values are ratios of the signal for the compound to an appropriate internal standard. All values are mean + 2 std. dev. except where a range is given... 

Figure 12.8 Observed/calculated polyhedral bond valence sum ratio around Cr octahe-dra as a function of the crystal field strength. Labels refer to values of chromium end-terms for the following solid solutions jadeite-kosmochlor (Ksm), grossular-uvarovite (Uvr), YAlOa-YCrOa perovskite (YCr), LaGaOs-LaCrOs...

The shape of the bands in Figure 6.8(a) can be derived from orbital overlap considerations for various values of k. The x-axis no longer has numerical values, instead it has letters labeling various points. These labels refer to different values of the wavevector the F point corresponds to kx = 0,ky = 0 the X point corresponds to kx = nja, ky = 0, and the M point corresponds to kx = n/a,ky = nja. To show the entire electronic structure, a three-dimensional plot with axes of kx, ky and... 

State State label Reference probability value Probability range... 

FIGURE 7.3 Disparity indices for the sepiids (labels refer to biogeographic units). Species richness is indicated by grey bars (no scale see Figure 7.2 for exact values). 

The HyperChem MMh- code and program also differ from MM2(1977) by having parameters in text files separate from the code. These parameter files are available for your modification and additions. The parameters distributed with HyperChem include the public domain values, generally referred to as the MM2(1991) parameter set, that Dr. Allinger contributed to HyperCube, Inc. Parameters not obtained from Dr. Allinger are appropriately labeled in the distributed parameter files. 

---