摘要
在豆芽食品中对添加的植物生长调节剂的监控是十分重要的。在此基础上建立了绿豆芽抽提样品中赤霉素、6-苄基腺嘌呤、4-氯苯氧乙酸和2,4-二氯苯氧乙酸4种植物生长调节剂的二维液相色谱定量分析方法。实验中以ZB-10 C18(ODS-AP,10 mm×10 mm)为第一维色谱柱,V(甲酸)∶V(甲醇)∶V(水)=1∶10∶89溶液等度洗脱,实现绿豆芽样品的前处理净化;随后通过阀切换将分析物转移至第二维色谱柱(Supersil ODS 2. 5μm,4. 6 mm×150 mm),以甲醇-0. 1%甲酸水溶液为流动相梯度洗脱,并以紫外254 nm为检测波长实现上述4种植物生长调节剂的分离分析。该方法中,赤霉素、6-苄基腺嘌呤、4-氯苯氧乙酸和2,4-二氯苯氧乙酸的线性范围分别为0. 004~2、0. 000 1~0. 2、0. 005~2以及0. 008~2 mg/m L,检出限分别为1. 4、0. 03、1. 6、2. 4μg/m L;峰面积的RSD为2%~3%,回收率为95%~104%。实际样品的分析中,发现该绿豆芽样品中赤霉素和2,4-二氯苯氧乙酸的添加量为0. 018 mg/g和0. 006 mg/g,4-氯苯氧乙酸未检出。另外,还发现样品中由于存在干扰物而不能准确定量分析低浓度的6-苄基腺嘌呤。研究表明,该方法可以应用于绿豆芽的直接抽提样品,对其中的赤霉素、4-氯苯氧乙酸和2,4-二氯苯氧乙酸能准确进行定量分析,不需进一步的样品前处理。
A method for simultaneous determination of gibberellin acid,6-benzyladenine,4-chlorophenoxyacetic acid and 2,4-dichlorophenoxyacetic acid in mungbean sprouts was established by 2 D-LC.The separation was first performed on the first-dimension column ZB-10 C18( ODS-AP,10 mm×10 mm).The analysts were trapped on this column for purification and the mobile phase used here was V( formic acid) ∶ V( methanol) ∶ V( water) = 1 ∶ 10 ∶ 89 in isocratic elution mode. Then,the trapped analysts were transferred to the second-dimension column( Supersil ODS 2. 5 μm,4. 6 mm×150 mm) using valve-switching technique,methanol and 0. 1% formic acid water solutions were used as mobile phase in gradient elution mode.Thus,they could be determined at254 nm with a UV detector.The results showed that the linear ranges of gibberellin acid,6-benzyladenine,4-chlorophenoxyacetic acid and 2,4-dichlorophenoxyacetic acid were 0. 004 ~ 2,0. 000 1 ~ 0. 2,0. 005 ~ 2 and 0. 008 ~ 2 mg/m L,respectively; and their detection limits were 1. 4,0. 03,1. 6 and 2. 4 μg/m L,respectively.The RSD values were 2% ~ 3% and the recoveries ranged from95% ~ 104%.When those plant hormone residues were purified by the first-dimension column,they could be successfully detected in mungbean sprouts at the level of 0. 018 mg/g for gibberellin acid and 0. 006 mg/g for 2,4-dichlorophenoxyacetic acid; It was also found that 4-chlorophenoxyacetic acid was not detectable and 6-benzyladenine could not be accurately determined in these extracts.The method is accurate and reliable,and can be applied directly to the determination of gibberellins acid,4-chlorophenoxyaceti acid,and 2,4-dichlorophenoxyacetic acid from the extracts of mungbean sprouts without further sample preparation,but not for 6-benzyladenine.
引文
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