REFLUX PREDIGESTION IN MICROWAVE SAMPLE PREPARATION

被引:5
作者
REID, HJ [1 ]
GREENFIELD, S [1 ]
EDMONDS, TE [1 ]
KAPDI, RM [1 ]
机构
[1] LOUGHBOROUGH UNIV TECHNOL,DEPT CHEM,LOUGHBOROUGH LE11 3TU,LEICS,ENGLAND
关键词
MICROWAVE DIGESTION; SAMPLE PREPARATION;
D O I
10.1039/an9931801299
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
In order to prevent excessive pressure rises in closed microwave acid digestion of fairly large (1 g) samples of high organic content, an open-vessel pre-digestion technique under reflux was designed to allow the escape of oxidation products, such as carbon dioxide, without incurring evaporation losses of acid or analytes. A microwave-transparent coolant liquid was circulated through a specially designed reflux condenser fitted onto an uncapped, commercially available digestion vessel, whilst samples and acid were heated in a microwave oven. Following pre-digestion, the vessels were capped and subjected to microwaves under pressure to complete the digestion. To test the method, 1 g samples of powdered sweet bay were digested with nitric acid using an open pre-digestion with and without reflux cooling, and the mass loss incurred compared with that using a completely closed method (where loss would be restricted to that due to oxidation reactions and release of carbon dioxide). The reflux and closed methods showed similar small mass losses, whereas those where reflux had not been used showed much higher losses, reflecting considerable evaporation of acid. Analysis of the digests for manganese by flame atomic absorption spectrometry showed no significant losses of analyte using either method.
引用
收藏
页码:1299 / 1302
页数:4
相关论文
共 14 条
[1]   SUPERHEATING EFFECTS ASSOCIATED WITH MICROWAVE DIELECTRIC HEATING [J].
BAGHURST, DR ;
MINGOS, DMP .
JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 1992, (09) :674-677
[2]   DESIGN AND APPLICATION OF A REFLUX MODIFICATION FOR THE SYNTHESIS OF ORGANOMETALLIC COMPOUNDS USING MICROWAVE DIELECTRIC LOSS HEATING EFFECTS [J].
BAGHURST, DR ;
MINGOS, DMP .
JOURNAL OF ORGANOMETALLIC CHEMISTRY, 1990, 384 (03) :C57-C60
[3]  
BOND G, 1991, CHEM IND-LONDON, P686
[4]   APPLICATIONS OF MICROWAVE DIGESTION TECHNIQUE FOR ELEMENTAL ANALYSES [J].
KUSS, HM .
FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY, 1992, 343 (9-10) :788-793
[5]  
MATUSIEWICZ H, 1989, PROG ANAL SPECTROSC, V12, P21
[6]  
MCCARTHY HT, 1991, J ASSOC OFF ANA CHEM, V74, P566
[7]   APPLICATIONS OF MICROWAVE DIELECTRIC HEATING EFFECTS TO SYNTHETIC PROBLEMS IN CHEMISTRY [J].
MINGOS, DMP ;
BAGHURST, DR .
CHEMICAL SOCIETY REVIEWS, 1991, 20 (01) :1-47
[8]   A SIMPLE MODIFICATION OF A DOMESTIC MICROWAVE-OVEN FOR IMPROVED TEMPERATURE CONTROL [J].
PAGNOTTA, M ;
NOLAN, A ;
KIM, L .
JOURNAL OF CHEMICAL EDUCATION, 1992, 69 (07) :599-600
[9]   APPLICATION OF MICROWAVE DIGESTION TO THE ANALYSIS OF PEAT [J].
PAPP, CSE ;
FISCHER, LB .
ANALYST, 1987, 112 (03) :337-338
[10]  
PATTERSON KY, 1988, INTRO MICROWAVE SAMP, P155