**5.4. Food dyes**

extraction with two solvents, e.g. ethanol and saline, and the potential for control of EA

Thehypothesis thatanionsofBPAmightberemovedbycolumnchromatographywithOctolig® was consideredbutnotpursuedbecauseofthewarnings inaMSDS (Material SafetyData Sheet)

The expectation of success was limited, based on the hypothesis and the prediction based on

made annually worldwide [ 49]. Dye-containing effluents can make their way into runoff and wastewater, eventually settling in the soil. As these workers noted [48], with textile industries, as much as 50% of the dyes can be lost and disposed in effluents [50]. These dyes can have adverse effects on the environment and ecosystems they pollute. Previous extraction methods have had limited success in removal from soil, and a recent approach involved the use of Fenton's reagent with electrochemistry[48] testing removal of Lissamine Green (Figure 9) from

Martin and Nabar [51] noted that previous studies [39] had demonstrated the ability to remove Lissamine Green from aqueous solutions, using column chromatography with Octolig® so it might be cheaper to extract Lissamine Green from soil using hot water, then remove the Lissamine by column chromatography with Octolig®. They were successful with kaolin and montmorillonite, but discovered that mixtures of clay and peat were less successful depending on the amount of peat present, then success of extraction decreasing linearly with the concen‐ tration of peat present. accordingly, the two step procedure would save same on electricity,

depending on the availability of hot water and the type of soil present.

tons) are

about hazards of BPA and because the pKa values of BPA were listed as 9.59 and 11.3.

As Rosales and co-workers noted [48 ], vast amounts of chemical dyes (around 106

materials in plastics may be considered.

available data (Figure 6).

a pseudo-soil matrix (kaolin).

**Figure 9.** Structure of Lissamine Green

**5.3. Dyes**

138 Column Chromatography

*Other dyes* such as food dyes may be commonly present, but the amount actually used is uncertain, and some workers have been concerned with the impact of these commonplace substances.

Food dyes are among the commonplace aspects of our daily life that may need more scrutiny [52].. These artificial colors are added to food for several reasons, chiefly to make the food more appealing, or perhaps fool the consumer into thinking the food has fruit or other helpful ingredients [52]. As noted elsewhere [52], synthetic food dyes have no nutritional value, they have no health benefits, they are not preservatives, but they do make us feel good about eating the food.

One significant concern is the suspicion that for over three decades the dyes have not been safe for all consumers[52, 53] Specifically some dyes are suspected of being responsible for behavioral problems in children., including "short attention span, aggressiveness, impulsivity, distractibility[54]." Feingold is credited with proposing that food dyes induce or aggravate symptoms of hyperactivity in children [55], and suggesting a "Feingold diet" is one that eliminates artificial food colorings.

Conflicting results, however, made it difficult to determine whether a Feingold diet is benefi‐ cial, despite a number of studies that have been conducted that have led to the view that food dyes did impair performance of hyperactive children [54], or did not in a controlled study [56], or that it did and that a one-week experimental diet could be used to detect a "sub-group of children hyperactive from specific food dyes[57]."

One common food dye is FD&C No 1 (Figure 10), a dye which should be removable by column chromatography by Octolig® were this to be desired. The structure (Figure 10) showing sulfonate groups indicates on the basis of Figure 6 that a low pKa would be expected, as would be ease of separation.

**Figure 10.** Structure of blue dye FD&C No 1 [Brilliant Blue FCF]

Using the *standard method*, noted earlier, quantitative removal (100.1+±0.04 %) of FD&C No 1 was achieved [58] This is one of seven food dyes approved for use in the United States under the Pure Food and Drug act of 1906 (abbreviated as FD&C), the other six dyes also appear to be easily removable by Octolig® based column chromatography based on an consideration of their structure.

adequate to remove all the sample in the supernatant (which is an asset for measuring capaci‐ tyofthesolid).Butthereareatleastthreeapplicationsofthebatchmethodthatcanbeconsidered.`

Chromatographic Separations with Selected Supported Chelating Agents

http://dx.doi.org/10.5772/55521

141

*One application* was determining the time course for of the batch methods. The example (Figure 13) shows the time course of removal can be fairly rapid, and an estimate of the capacity is

**Figure 12.** method with Octolig®: Percent removed by Octolig® as a function of time for aqueous 3-nitrophenol. Octo‐ lig® was suspended in 100 mL of aqueous 3-nitrophenol) and shaken (.at a rate of 240 rpm. Aliquot portions taken

A *second application* of the batch method was being able to evaluate a mechanism of sorption,

A *third application* was that of comparison. Many in academe seem to have favored batch methods. In contrast, a valued colleague [9, 10] noted that information obtained from column chromatography was more applicable to the needs of industry. Column chromatography was

Accordingly, a series of experiments was designed and performed to evaluate comparisons of batch versus column chromatography (cf. Table 7). A *standard batch method* is presented here for the sake of comparison [59]. A sample of Octolig ® (5 g as received) was placed in a 250 mL Erlenmeyer flask covered with 100 mL of about 1600 ppm phosphate as NaH2PO4. The samples were placed in a gyrotory water bath and subjected to shaking (>170 rpm) overnight. At the end of the shaking period, an aliquot was removed, and diluted ca. 1:8 for phosphate. Mean and SD values were calculated. The result was subtracted from the initial phosphate

concentration to determine the capacity, expressed as moles per kg of Octolig®.

periodically as noted and analyzed. (Figure from [47], used with permission of the author).

used with Octolig® in practical applications as noted previously.

indicated by the "plateau phase."

as noted by Gao and co-workers [13].

**Figure 11.** FiFD&C No 3., Erythrosine B, R1 = I ; R2 = H


**Table 6.** Column chromatography of aqueous Erythrosine B samples over a 3.0 cm (id) column packed with ~130 mL of Octolig® at a flow rate of 10 mL/min (50-mL aliquots were collected and concentrations of fractions 4-10 were measured spectrophotometrically) [44]

Similarly, using our standard method for column chromatography, quantitative separation was obtained. for Erythrosine, but also for the other food dyes in contemporary use It is also notable that there was no significant matrix effect observed for DI, tap or well water.
