ADVERTISING SUPPLEMENT Food and Bevera g e 5 3 THE A P P L I C AT I O N NOTEBOOK — June 2005 Determination of Glucose, F r u c t o s e, and Sucrose in Maple Syrup

Randy Benton, M e t rohm-Peak, Inc

aple syrup is produced by boiling the sap from va r i o u s Results and Discussion M types of maple trees. Ge n e r a l l y, it is produced in the With the adulteration of maple syrup as a growing concern a sim- No rtheastern United States and Canada in late winter or early ple yet rugged method is needed to determine if syrup has been spring when the sap of the tree is running. Many other pro d u c t s a l t e red. Larger peak area and concentration values are expected in such as maple sugar, maple butter (cream), maple candies, and more s y r up that has been altered. For this study, samples of maple syru p a re also produced using the sap from maple trees. One issue pro- we re diluted, fil t e red, and then injected for analysis. A sample of d u c e r’s face is that of adulteration of the syrup by the addition of u n a l t e red maple syrup was spiked with high-fructose corn syrup to either corn syrup or cane sugar. A small amount of either of the two determine if a change would be seen. This was indeed the case. Fi g- does not noticeably change the taste of the syrup but it drastically u re 1 is a stacked chromatogram of three separate injections of unal- i n c reases the sugar production of the syru p. t e red maple syrup (red, green, and blue) and one injection of a sam- The determination and quantification of sugars by pulsed-amper- ple spiked (black) with high-fructose corn syru p. ometric detection (PAD) is a well accepted technique. Cu r re n t l y, sugar producers rely on a complex carbon-isotope ratio test to deter- C o n c l u s i o n mine if the syrup had indeed been adulterated. The detection of Using this method, sugar concentrations can be determined in less sugars by PAD, specifically glucose, fructose, and sucrose and their than 20 min, increasing the efficiency of testing. The instru m e n t concentrations, could be used as an alternative to the method cur- used is simple, rugged, and ve r y reliable. There is no need for haz- rently in use. a rdous chemicals or their disposal. This method also reduces the cost to the laboratory for purchasing expensive instruments such as Experimental Conditions a mass spectro m e t e r. If samples are suspect, it is a simple matter to A Me t roh m Ad vanced Ion Chromatography system equipped with dilute and then inject the samples. Pu l s e d - a m p e rometric detection a Me t rohm Model 818 IC Pu m p, Me t rohm 788 Ad va n c e d of carbohydrates is a well re c o g n i zed and useful tool in industries Au t o s a m p l e r, Me t rohm 817 Bioscan Pulsed Amperometric De t e c - such as food and food additives, animal feed, pharmaceutical, and t o r, and a 830 IC interface was used for the analysis. Data acquisi- others for the detection and quantification of carbohydrates. This tion and processing we re performed with Me t rohm IC-Net 2.3 method would be especially useful for the detection of adulterated s o f t w a re. Bioscan temperature was controlled at 320 °C. The col- maple syrup samples. umn employed for analysis was the Me t rosep Carb 1 (150 mm 3 4 mm). The Eluent used was 100-mM sodium hyd roxide at a flow R e f e re n c e s rate of 1 mL/min. The injection volume was 10uL. ( 1 ) “Metrohm Application Works AW-US6-0101-042005,” Metrohm-Peak, Inc. (Houston, Texas).

M e t roh m-Peak, Inc. Figure 1: Stacked chromatogram of three separate injections of maple syrup and one spiked sample. 12521 Gulf Fre e w a y, Houston, TX 77034 tel. (800) 410-7118, fax (281) 484-5001 i n f o @ m e t rohm-peak.com, www. m e t ro h m - p e a k . c o m For More Information Circle 42