Soft drinks solvents

Phenol was the first commercial antiseptic its introduction into hospitals in the 1870s led to a dramatic decrease in deaths from postoperative infections. Its use for this purpose has long since been abandoned because phenol burns exposed tissue, but many modern antiseptics are phenol derivatives. Toluene has largely replaced benzene as a solvent because it is much less toxic. Oxidation of toluene in the body gives benzoic acid, which is readily eliminated and has none of the toxic properties of the oxidation products of benzene. Indeed, benzoic acid or its sodium salt (Na+, C6H5COO ions) is widely used as a preservative in foods and beverages, including fruit juices and soft drinks. 

These results, considered in relation to the direct addition tests of monomer and hydrogen cyanide in the previous table, demonstrate that there is no reason to expect styrene monomer extraction into soft drinks, even at levels well below those we can measure analytically. They also reinforce our hydrogen cyanide data. Further, they indicate that these beverages are not more extractive of Lopac containers than the normal simulating solvents. The tests confirm the chemical safety of the containers as beverage packages. 

Additive (dried flower meal or solvent extract) to poultry feed, to enhance the yellow color of flesh and egg yolks minor use of extract as food colorant typical applications salad dressings, ice cream, dairy products, other foods with high fat contents, soft drinks, bakery products, jams and confectionery... 

Atomic absorption spectrometry is one of the most widely used techniques for the determination of metals at trace levels in solution. Its popularity as compared with that of flame emission is due to its relative freedom from interferences by inter-element effects and its relative insensitivity to variations in flame temperature. Only for the routine determination of alkali and alkaline earth metals, is flame photometry usually preferred. Over sixty elements can be determined in almost any matrix by atomic absorption. Examples include heavy metals in body fluids, polluted waters, foodstuffs, soft drinks and beer, the analysis of metallurgical and geochemical samples and the determination of many metals in soils, crude oils, petroleum products and plastics. Detection limits generally lie in the range 100-0.1 ppb (Table 8.4) but these can be improved by chemical pre-concentration procedures involving solvent extraction or ion exchange. 

None of the involved species are fluorescent. Therefore, for fluorescence signaling of citrate recognition, carboxyfluorescein is first added to the medium because binding to the receptor in the absence of citrate is possible and causes deprotonation of carboxyfluorescein, which results in high fluorescence. Citrate is then added, and because it has a better affinity for the receptor than carboxyfluorescein, it replaces the latter, which emits less fluorescence in the bulk solvent as a result of protonation. Note that this molecular sensor operates in a similar fashion to antibody-based biosensors in immunoassays. It was succes-fully tested on a variety of soft drinks. 

Another RP-HPLC technique has been applied for the determination of synthetic food dyes in soft drinks with a minimal clean-up. Separation of dyes was obtained in an ODS column (150 x 4 mm i.d. particle size 5 pm). Solvents A and B were methanol and 40 mM aqueous ammonium acetate (pH = 5), respectively. Gradient conditions were 0-3 min, 10 per cent A 3-5 min, to 25 per cent A 5-8 min, 25 per cent A 8-18 min, to 75 per cent A 18-20 min, 75 per cent A. The flow rate was 1 ml/min and dyes were detected at 414 nm. The separation of synthetic dyes achieved by the method is shown in Fig. 3.35. The concentrations of dyes found in commercial samples are compiled in Table 3.21. The quantification limit depended markedly on the type of dye, being the highest for E-104 (4.0 mg/1) and the lowest for E-102 and E-110 (1.0 mg/1). The detection limit ranged from 0.3 mg/1 (E-102 and E-110) to 1.0 mg/ml (E-104 and E-124). It was suggested that the method can be applied for the screening of food colourants in quality control laboratories [113]. 

Caffeine is a naturally occurring substance found in the leaves, seeds, or fruits of more than 60 plants. These include coffee and cocoa beans, kola nuts, tea leaves, guarana (Paulinia cupana) and Paraguay tea. Thus it is present naturally in many beverages, such as coffee, tea, and cola drinks, or is added in small amounts (up to 200 ppm) in some soft drinks and in foods such as chocolate. Caffeine is obtained by solvent or supercritical fluid extraction from green coffee beans, mainly during the preparation of decaffeinated coffee. 

As with all methods, this approach has some limitations it uses acetonitrile, which is toxic, and the separation of glucose from fructose can sometimes be problematic after extended use of the column. However, sample preparation is easy since it requires only dilution to the required level (often 1 10) and filtration prior to analysis to remove particulate materials, which protects and extends the useful life of the column. The degradation of the resolution between glucose and fructose is caused by the partial inactivation of the column by materials in the matrix, but this resolution can be recovered by reducing the acetonitrile concentration in the solvent. The same column can also be used to assay the level of ascorbic acid (vitamin C) in a soft drink or fruit juice, although different detection and solvent systems are used. 

Two methods have been published which were designed to analyse a range of sweeteners and preservatives in one run. The fust method, published in German by Hagenauer-Hener et al. (1990), describes the analysis of aspartame, acesulfame K, saccharin, caffeine, sorbic acid and benzoic acid in soft drinks and foods. The method relies on a similar system to that given above but with a less complex solvent system (Figure 10.5). The solvent system has been modified to include a gradient portion to elute the preservatives more quickly. 

Figure 10.5 Separation of soft drinks ingredients using the method of Hagenauer-Haner et al. (1990). Solid line is orange squash dotted line is mixed standard. Conditions column PR8 5 xm 150 X 4.6 mm solvent = 0.02 M phosphate buffer/acetonitrile (90 10) flow rate 1 ml/min using UV detection 220 nm, time 10 10% to 70% acetonitrile over 15 min.

Benzoic and sorbic acids are now normally assayed using HPLC. As discussed in the section on the analysis of sweeteners, some of the HPLC methods developed for soft drinks actually allow the separation of both sweeteners and preservatives in one ran, for example, Williams (1986), Hagenauer-Hener et al., (1990) and the EU method for sweeteners (Anon, 1999a), although the preservatives were not included in the collaborative trial of the method. The separation of benzoic and sorbic acids can sometimes be difficult and care should be taken that the system will actually resolve these two preservatives if they are present otherwise spurious results can be obtained. The pH of the solvent is a critical feature that allows the separ ation of these two preservatives. 

Two compounds that are used in some soft drinks formulations for specific purposes are caffeine, used in a range of beverages including colas for its stimulant properties, and quinine, used for its bitter taste. Traditional techniques for the analysis of these two compounds have often involved their extraction from aqueous solution into an organic solvent and then quantification by one of a range of methods. 

The cinnamon of commerce is the dried inner bark of the tree, C. vemm. ft is an essential item in curry powders and masalas. The bark oil, bark oleoresin and leaf oil are important value-added products from cinnamon. Bark oil is used in the food and pharmaceutical industries. Cinnamon leaf oil is cheaper than bark oil and is used in the flavour industry. Cinnamon oleoresin, obtained by solvent extraction of the bark, is used mainly for flavouring food products such as cakes and confectionary. As in the case of cinnamon, the volatile oil and oleoresin from cassia are also used extensively in flavouring, especially soft drinks and other beverages. 

Esters are widely used in industry as solvents. Ethyl acetate is a good solvent for a wide variety of compounds, and its toxicity is low compared with other solvents. Ethyl acetate is also found in household products such as cleaners, polishes, glues, and spray finishes. Ethyl butyrate and butyl butyrate were once widely used as solvents for paints and finishes, including the butyrate dope that was sprayed on the fabric covering of aircraft wings to make them tight and stiff. Polyesters (covered later in this section and in Chapter 26) are among the most common polymers, used in fabrics (Dacron ), films (VCR tapes), and solid plastics (soft-drink bottles). 

Benzene is a very widely used solvent and industrial chemical and a component of petroleum. It is a ubiquitous air pollutant and is formed as a decomposition product in fruit and soft drinks that are preserved with benzoates. Benzene is a known leukemogen and the one to which other leukemia-causing chemicals are compared. I37-39 Even low level exposure to benzene has been shown to induce leukemia. I39 40 Benzene has also been associated with lung and nasopharynx cancers. ... 

Traditionally, essential oils were used as beverage flavorings (soft drinks), in the perfume industry and for other chemical uses. In this sense, other applications such as solvents and pesticides have been documented (Braddock, 1999). Furthermore, useful chemicals have been obtained from chemical reactions of limonene (Thomas and Bessiere, 1989). 

What are the solvent and solute components in the following examples a. Steel b. Vinegar c. Soft drinks d. Tap water... 

Sucrose is used as a sweetener in teas, coffee, and a host of soft drinks. The solvent in all of these beverages is water, a polar molecule. The rule "like dissolves like" implies that sucrose must also be a polar molecule. Without even knowing the formula or structure of sucrose, we can infer this important information from a simple experiment—dissolving sugar in our morning cup of coffee. 

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