Study On Determination Of Plant Growth Regulators Residues In Fruits And Vegetables

In recent years, obvious economical benefit have been got by people due to theplant growth regulators used in the agriculture, however, the plant growth regulatorsremained in the fruit and vegetables is insecurity for people health. So, detecting thecontent of the plant growth regulators can supervise food safety, and provide scientificbasis for apply the plant growth regulators. Nine kinds of plant growth regulators wasstudied in this paper, they are Gibberellin (GA3)、6-Benzylaminopurine、Parachlorophenoxyacetic acid、 Thidiazuron、 Indolebutyric acid、2,4-Dicholrophenoxyacetic acid、α-Naphthalene acid、Forchlorfenuron、ethephon.Adopt high performance liquid chromatographic (HPLC)、high performance liquidchromatography–electrospray ionization tandem mass spectrometric (HPLC-ESIMS/MS) method research the plant growth regulators detection.(1) A high performance liquid chromatographic (HPLC) method was developedfor the determination of eight plant growth regulators in fruits and vegetables at thesame time. The samples were analyzed on an ODS2C18(200×4.6mm,5μm) column,and the acetonitrile/phosphoric acid-diammonium hydrogen phosphate (0.01mol/L,pH=3.50) were as the mobile phase gradient elution, and the wavelength was changed.The eight plant growth regulators, including Gibberellin (GA3)、6-Benzylaminopurine、Parachlorophenoxyacetic acid、Thidiazuron、Indolebutyricacid、2,4-Dicholrophenoxyacetic acid、α-Naphthalene acid、Forchlorfenuron wereseparated. The samples were quantified with the external standard calibration curvemethod, the relative standard deviations (RSDs) were low in6.43%, the detectionlimit of method was between0.26to0.75mg/kg. The method was used to detect thecontents of plant growth regulators in fruits and vegetables, three spiked concentrationlevels of2.50、10.0、25.0mg/kg were added in the samples, recoveries were from80.0%to106.0%. The result showed the method was applicable for detect of plant growth regulators.(2) A high performance liquid chromatography–electrospray ionization tandemmass spectrometric (HPLC-ESI MS/MS) method was developed for the determinationof seven plant growth residues，including parachlorophenoxyacetic acid, gibberellicacid (GA3),2,4-dichlorophenoxyacetic acid, α-naphthaleneacetic acid, indolebutyricacid,6-benzylaminopurine, forchlorfenuron, in fruits and vegetables. Plant growthregulators were extracted from samples with methanol twice and the extracts werecleaned up on a Waters C18solid phase extraction column (SPE,0.5g,3mL).Qualitation of the analytes was with selective reaction monitoring (SRM) andexternal standard method was used for quantification. The effect of chromatographyseparation was good for gradient mode, while the methanol and water as eluent use aHpersil GOLD aQ (150mm×2.1mm,3μm) column. Under the optimal conditions,good linearities were obtained for seven plant growth regulators with correlationcoefficients above0.9935. Average recoveries of seven plant regulators from fruitsand vegetables samples at three spiked levels ranged from79%to97%, with relativestandard deviations (RSDs) less than7.6%. The limits of detection (LODs) were inthe range of0.40-20.0μg/kg. The result showed the method was simple and sensitive,and was applicable for detection of plant growth regulators.(3) A high liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)method was developed for the determination of ethephon in fruits and vegetables. Theethephon was extracted using methanoic acid and methanol (v: v=1:20), it wasanalysed on Hypersil GOLD aQ (150mm×2.1mm，3μm) and separated by gradientelution with methanoic acid and methanol (pH=3.00). The qualitation of the analyteswas achieved under selective reaction monitoring (SRM)、negative ion mode, and thequantification of the analytes was carried out by external standard method. The goodlinearities (r2=0.9993) were achieved for the ethephon over the range of50.0-1000.0 μg/kg. Three spiked concentration levels of50.0、250.0、500.0μg/kg were added inthe samples, the recoveries for the ethephon ranging from75.4%-77.5%, relativestandard deviation (RSD) was low in7.35%. The method limit of detection (LOD)was10.0μg/kg. This method was simple、accurate, it is very suitable for the ethephonin fruits and vegetables detecting.