Acesulfame detection systems

Reproductive toxicity of acesulfame K was studied in test systems aimed at detecting teratogenicity, oral embiyotoxicity and in a multigeneration study. No teratogenicity, no embryotoxicity, and no effects on reproduction, development of the fetuses and lactation performance were found.7... 

To illustrate the hyphenation between FIA and HPLC, a system for food additives (acesulfame-k, saccharin, caffeine, benzoic acid and sorbic acid) determination [40] is shown in Figure 3.14. The system includes a dialysis cell in order to eliminate the sample matrix. Thus, a peristaltic pump dispenses the sample, which is loaded into a holding coil of an injection valve (IVl) and later injected into the donor stream. Both, donor and acceptor streams are also propelled by the peristaltic pump. Once the dialysis has been performed, analytes are loaded into a holding coil of a second injection valve (IV2). At this point, the sample passes to the HPLC system. The sample is injected into a mobile phase stream dispensed by the HPLC pump. So, the pretreated sample passes through the precolumn and column, and the analytes are separated and detected. Thus, the treatment, separation and detection steps are carried out in an efficient and high automated way. 

RPLC with MS detection was used for the analysis of seven artificial sweeteners (aspartame, saccharin, acesulfame-K, neotame, sucralose, cyclamate, and alitame) and one natural sweetener (stevioside). Samples were extracted using methanokwater and injected without any cleanup into the LC—MS system. Separation is carried out using a Cis column and gradient elution. Sweeteners were quantified using selective-ionization recording (SIR) at m/z 178, 397, 377, 293, 641, 312, 162, and 182 for cyclamate, sucralose, neotame, aspartame, stevioside, alitame, acesulfame-K, and saccharin, respectively, with a warfarin sodium m/z = 307) used as an internal standard [24]. For a detailed discussion of other analytical methods to determine artificial sweeteners, refer to [25]. 

Some sweeteners (aspartame, cyclamate, saccharin, and acesulfame K) were determined by CE-SIA with contactless conductivity detection (Stojkovic et al., 2013). The analyses were carried out in an aqueous running buffer consisting of 150 mM 2-(cyclo-hexylamino)ethanesulfonic acid and 400 mM tris(hydroxymethyl)aminomethane at pH 9.1 in order to render all analytes in the fully deprotonated anionic form. The four compounds were determined successfully in food samples the experimental set-up and typical analysis results are illustrated in Figure 2.9. Another SIA system combined with solenoid valves was used to automate an enzymatic method for the determination of aspartame in commercial sweetener tablets. The method involves the enzymatic conversion of aspartame to hydrogen peroxide by the chymotrypsin-alcohol oxidase system, followed by the use of 2,2-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ARTS) as electron donor for peroxidase. Chymotrypsin and alcohol oxidase enzymes were immobilized on activated porous silica beads (Pena et al., 2004). 

A monolithic minicolumn was incorporated in a FIA manifold for the simultaneous analysis of eight analytes, including sweeteners (aspartame, acesulfame-K, saccharin) and a few preservatives and antioxidants (Garcia-Jimenez et al., 2007). The singlechannel FIA system with a short monolithic C18 column, which allowed the separation of analytes according to their retention time, was used for quantification by measuring the intrinsic UV absorption of the analytes. The system was applied to the detection in different foodstuffs and the results obtained were in agreement with a reference FiPLC method. 

A flow injection system coupled to a monolithic column has been described for the simultaneous determination of antioxidants (PG and BHA), sweeteners (potassium acesulfame, sodium saccharin, and aspartame), and preservatives (methylparaben, eth-ylparaben, propylparaben, and butylparaben), using photometric detection [56]. The monolithic column used as separation system was a 5 mm commercial precolumn of silica Cjg. The mixture was separated in only 400 s with resolution factors greater than 1.1 in all cases. Detection was accomplished by means of a DAD at the respective wavelength of each compound. The detection limit obtained for PG was 0.02 pg/mL. The method was applied to the analysis of food and cosmetic samples and the results were compared with those obtained using a conventional LC method. 

No methods could be found in the literature for the individual flow analysis determination of acesulfame-K. The first flow analysis method for acesulfame-K was proposed by Nikolelis et al. 2001 [72]. This method allowed the electrochemical flow injection monitoring and analysis of mixtures of acesulfame-K, cyclamate, and saccharin using stabilized systems of filter-supported bilayer lipid membranes (BLMs). Detection consisted of t time-dependent appearance of a transient ion current peak in which the time-dependence could be used to distinguish the presence of different artificial sweeteners, and the peak magnitude was related to the concentration of the artificial sweetener. The BLM-based system is able to monitor each artificial sweetener in mixtures. The apparatus for the formation of stabilized BLMs is shown in Figure 24.4. The method also offers response times of less than 1 min, which are the fastest times reported for any similar... 

Kritsunankul et al. [76] proposed flow injection online dialysis for sample pretreatment prior to the simultaneous determination of some food additives by HPLC and UV detection (FID-HPLC). For this, a liquid sample or mixed standard solution (900 pL) was injected into a donor stream (5%, w/v, sucrose) of a FID system and was pushed further through a dialysis cell, while an acceptor solution (0.025 mol/L phosphate buffer, pH 3.75) was held on the opposite side of the dialysis membrane. The dialysate was then flowed to an injection loop of the HPLC valve, where it was further injected into the HPLC system and analyzed under isocratic reversed-phase HPLC conditions and UV detection (230 nm) (Figure 24.6). The order of elution of five food additives was acesulfame-K, saccharin, caffeine, benzoic acid, and sorbic acid, with an analysis time of 14 min. This system has advantages of high degrees of automation for sample pretreatment, that is, online sample separation and dilution and low consumption of chemicals and materials. 

Saccharin is also determined with FIA methodologies, which allow multianalyte determination. These methodologies include methods cited previously for acesulfame-K and/or cyclamate a method based on electrochemical detection of these three artificial sweeteners using stabilized systems of filter-supported BLMs [72] online dialysis for sample pretreatment prior to the simultaneous determination of saccharin and caffeine, benzoic acid, and sorbic acid by HPLC-FID [76] and molecular spectroscopic methods in the UV region based on the transient retention of analytes on solid phases, silica Cjg [74], and quaternary amine ion exchanger [75]. 

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