Resolution of an intense sweetener mixture by use of a flow injection sensor with on-line solid-phase extraction. Application to saccharin and aspartame in sweets and drinks.
An integrated solid-phase spectrophotometry-FIA method is proposed for simultaneous determination of the mixture of saccharin (1,2-benzisothiazol-3(2H)-one-1,1-dioxide; E-954) (SA) and aspartame (N-L-alpha-aspartyl-L-phenylalanine-1-methyl ester; E-951) (AS). The procedure is based on on-line preconcentration of AS on a C18 silica gel minicolumn and separation from SA, followed by measurement, at lambda = 210 nm, of the absorbance of SA which is transiently retained on the adsorbent Sephadex G-25 placed in the flow-through cell of a monochannel FIA setup using pH 3.0 orthophosphoric acid-dihydrogen phosphate buffer, 3.75x10(-3) mol L(-1), as carrier. Subsequent desorption of AS with methanol enables its determination at lambda = 205 nm. With a sampling frequency of 10 h(-1), the applicable concentration range, the detection limit, and the relative standard deviation were from 1.0 to 200.0 microg mL(-1), 0.30 microg mL(-1), and 1.0% (80 microg mL(-1), n = 10), respectively, for SA and from 10.0 to 200.0 microg mL(-1), 1.4 microg mL(-1), and 1.6% (100 microg mL(-1), n = 10) for AS. The method was used to determine the amounts of aspartame and saccharin in sweets and drinks. Recovery was always between 99 and 101%. The method enabled satisfactory determination of blends of SA and AS in low-calorie and dietary products and the results were compared with those from an HPLC reference method.
Capitán-Vallvey
L F
LF
Department of Analytical Chemistry, Faculty of Sciences, Campus Fuentenueva, University of Granada, 18071 Granada, Spain. lcapitan@ugr.es
Valencia
M C
MC
Arana Nicolás
E
E
García-Jiménez
J F
JF
D001218:Aspartame / Q000032:analysis*; D001628:Beverages; D002138:Calibration; D002627:Chemistry, Physical / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D003911:Dextrans / Q000737:chemistry; D017022:Flow Injection Analysis / Q000295:instrumentation* / Q000379:methods*; D005504:Food Analysis / Q000295:instrumentation* / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D010710:Phosphates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D012439:Saccharin / Q000032:analysis*; D012984:Software; D013053:Spectrophotometry / Q000295:instrumentation* / Q000379:methods; D013549:Sweetening Agents / Q000032:analysis*
D003911:Dextrans; D010710:Phosphates; D010756:Phosphoric Acids; D013549:Sweetening Agents; C025614:sephadex; C030242:phosphoric acid; D012439:Saccharin; D001218:Aspartame