Butyric acid, labelled with

Yin XB, Qi B, Sun XP, Yang XR, Wang EK (2005) 4-(dimethyl"-amino)butyric acid labeling for electrochemiluminescence detection of biological substances by increasing sensitivity with gold nanoparticle amplification. Anal Chem 77 3525... 

Figure 5. Fluorescence spectra of pyrene tagged novolac and free pyrene butyric acid (PBA) in diglyme. Spectra are labeled with percent of monomer units tagged. The pyrene concentration in solution is 1 x 10 bM, except in the inset where different pyrene concentrations are compared along with the spectra of a film containing the tagged polymer.

Attempts to label dangerous substances with either characteristic or outright unpleasant odors have not been successful with children, the primary victims of accidental poisonings by toxic household products. Children tolerate odors that adults find unpleasant, such as that of butyric acid. The range between the most pleasant and unpleasant odors is much narrower for children around 4years of age than for adults, and also much narrower than for taste stimuli. This means that olfactory cues are not suited to produce aversive responses in children (Engen, 1974b, Cain, 1978). 

Natural esters are widely used by the aroma and fragrance industries because of their fruity or floral taste/odor. Many of them are alkyl esters of formic, acetic, propionic, and butyric acids. The development of an efficient biotechnological process, compatible with the natural label for the products but offering costs comparable to the costs of chemical processes, has been achieved, representing the first application of gas/solid technology on an industrial scale [51]. 

The total yield of 201 was increased and the synthesis time reduced by extracting [nC]butyric acid from its lithium salt by dry 0.1% HCl/He gas mixture and carrying out its pyrolysis at 530 °C over glass beads (equation 104). The relative reactivity of 201 to primary, secondary and tertiary alcohols (equation 105a, b, c) has been found to be as 1 0.4 0.1, respectively. Several bioactive compounds have been labelled with [nC]propyl ketene, such as carbohydrate compounds193 and IV-butyl compounds, for instance /V- 11 C]butyryl THPO, 202, and some phorbol esters192, 203, 204 and 205. 

HeLa cells were cultured for 24 hr with (open bars) and without (closed bars) 5 mM sodium butyrate, harvested, and assayed for indicated enzyme activity. A GM3-sialidase activity assayed with GM3 specifically labeled with [,iC]- N-acetylneuraminic acid as substrate ("14JJ. B Sialyltrasferase activity assayed with CMP-[, acetylneuraminic acid and lactosylceramide as substrates, and synthesis of labeled GM3 determined (17). Data... 

This work used elution development with buffers of a-hydroxyiso-butyric acid partially neutralized with NHi OH, and Dowex 50W-X12 resin with a particle size range of 20—40 ym. The elution bands showed good separation of Es, Cf, Bk (the band labelled "3" is a combination of Bk and Eu), and Cm. The very small amount of Fm present in this early production material is in the extreme leading edge of the Es band. 

C16 polyketides respectively) with methionine providing, respectively, two and three Cl units. Results with [l,2- C2]acetate more rigorously defined the constitution of the polyketide fragment of cytochalasin D as that shown in (148). The reported intact incorporation of palmitic acid into brefeldin A (subsequently refuted) prompted the examination of l- C/ C-labelled palmitic and myristic acids together with butyric acid as cytochalasin D precursors. In each case incorporation was through C-1 labelled acetate resulting from fragmentation by way... 

As already indicated, a special problem with esters is their preparation from two natural precursor molecules by a chemical ester synthesis. Such products have to be labelled nature-identical. For an interesting positional H-NMR study on ethyl butyrate from enzymatic esterification of beet ethanol with butyric acid from milk see [317]. Another chance to detect a corresponding adulteration would be a positional carbon and oxygen isotope analysis of the ester components. Isotope effects on the esterification reaction in question seem to influence characteristically the 8-values of the atoms involved, and hence form a basis for the origin assignment of these compounds (for further details see 6.2.2.4.4). 

CEC, a hybrid separation technique of CE and HPLC, potentially combines the high efficiency of CE and the selectivity and versatility of HPLC. CEC was coupled with Ru(bpy)3 " ECL detection by Xu s group for the first time. Proline, putrescine, spermidine, and spermine were separated efficiently by this method at pH range of 3.5-7.0 of the mobile phase. The proposed detection scheme offers a powerful tool for analysis since CEC generally displays better resolution than CZE for neutral analytes and charged analytes with equal electrophoretic mobilities [69]. Dual-cloud point extraction (dCPE) and tertiary amine labeling has been used for sensitive and selective detection of two auxins employing CE-ECL. The proposed method shows feasibility to the detection of the two auxins in acacia tender leaves, buds, and bean sprout and the detection limits (S/N = 3) were 2.5 and 2.8 nM for indole-3-acetic acid (lAA) and indole-3-butyric acid (IBA), respectively. The proposed method was applied effectively to the detection of the two auxins in real samples [70]. 

Seasonings based on dairy products — Cheeses and sour creams are commonly used in snack seasonings. Natural cheeses are often used for label or familiarity purposes. Enzyme modified cheeses or creams are typically used to carry the flavor due to both flavor strength and cost issues. The dairy character of the seasoning may be fortified with other natural flavorings, e.g., lactic acid, butyric acid, diacetyl, etc. Examples of dairy-based snack seasonings are presented in Table 14.6 and Table 14.7. 

In 2000, Nohta et al. described a method for the determination of biologically active polyamines by intramolecular excimer-forming derivatization with 4-(l-Pjo ene)butyric acid N-hydroxysuccinimide ester (PSE) [34], By this method, dipyrene-labeled putrescine, cadaverine, spermidine, and spermine could be separated by reversed-phase liquid chromatography and specifically detected by the excimer fluorescence at 475 nm with excitation at 345 nm. The excimer fluorescence-emission wavelength is far different from that of the monomer fluorescence-emission wavelength (375 nm) derived from the excess PSE reagent, the hydrolysate product (4-(l-pyrene)butyric acid), and other monopyrene-labeled derivatives. In real biological samples, various monopyrene-labeled derivatives are formed by reaction with PSE and severely interfere with the determination of polyamines. 

Nimura, N. Kinoshita, T. Fluorescent labeling of fatty acids with 9-anthryldiazomethane (ADAM) for high performance liquid chromatography, Anal.Lett., 1980, 13, 191-202. [derivatization propionic acid butyric acid valeric acid caproic acid heptanoic acid capiylic acid capric acid lauric acid myristic acid linolenic acid linoleic acid palmitic acid stearic acid oleic acid]... 

DL-Norvaline-3-C on administration to rats or on incubation with rat liver homogenates yielded radioactive a-ketovaleric acid, butyric acid, acetic acid, acetoacetate, and 3-hydroxybutyric acid HI). These compounds were isolated by column cluomatography and their identity established. Degradation of the butyric acid demonstrated that only C-2 was significantly labeled. This established that the butyrate was formed by a direct pathway from norvaline and not by the subsequent condoisation of two-carbon fragments. 

In the first example, the sodium enolate of (S)-4-benzyl-3-[ 1 - " C]butyryl-1,3-oxazolidin-2-one (93) was treated with a tenfold excess of methyl iodide to afford a 95 5 mixture of the two a-methylated diastereomers 94 and 95. Preparative HPLC separation of 94 followed by cleavage of the auxiliary provided the free (S)-2-methyl[l- C]butyric acid (96) in overall 58% yield from sodium [l- " C]butyrate. Acid 96 was a key intermediate in the carbon-14 labeling of pravastatin, an antihyperlipoproteinemic drug, as well as for investigation of the biosynthesis and the biological labeling of avermectin Bia, currently marketed as a miticide/ insecticide . 

---