臺灣農藥科學第一期

臺灣農藥科學

(Taiwan Pesticide Science) 1: 178-182 (2016)

DOI: 10.6671/TPS/2016.001.09

Scientific Notes

Determination of Paraquat Residues in Adzuki

Beans (

Vigna angularis

)

Wei-Chen Chuang

, Chia-Wei Lin

, Chen-Hua Huang

, Tsyr-Horng Shyu

, Shao-Kai Lin

Abstract

Chuang, W. C., Lin, C. W., Huang, C. H., Shyu, T. H., and Lin, S. K. 2016. Determination of paraquat

residues in adzuki beans (

Vigna angularis

). Taiwan Pestic. Sci. 1: 178-182.

We developed a rapid and novel method to prepare and determine paraquat samples in

adzuki beans using liquid chromatography -- tandem mass spectrometry (LC-MS/MS). The

method is specifically used for adzuki beans since QuPPe-method (quick polar pesticides

method) gave poor recovery of paraquat residues in adzuki beans. Sample preparation involves

extraction with 1% formic acid/methanol, shaking of sample mixture, ultrasonication in a

hot water bath with a temperature of 80°C, and centrifugation. The extracts were then passed

through a 0.22-μm syringe filter into a plastic storage vial and subjected to LC-MS/MS analysis.

The validity of the method was assessed by evaluating intraday and interday recoveries at low

(0.05 mg/kg), medium (0.20 mg/kg), and high (0.50 mg/kg) levels of paraquat in adzuki beans.

Recoveries ranged from 63.3% to 98.3%. The limit of quantification (LOQ) was 0.05 mg/kg,

which may satisfy current regulatory needs in Taiwan.

Key words:

adzuki beans, LC-MS/MS, paraquat, residue analysis.

Accepted: August 26, 2016.

*Corresponding author, Email:

sklin@tactri.gov.tw

Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture. Taichung.

Introduction

In this study, we developed a rapid and

sensitive method for the preparation and deter-

mination of paraquat samples in adzuki beans

using liquid chromatography -- tandem mass

spectrometry (LC-MS/MS). Paraquat is a non-

selective contact herbicide used for broad-

spectrum control of broad-leaved weeds and

grasses in various crops

(4)

. It is also used as a

harvest-aid for dry beans, including adzuki

beans

(3)

. Adzuki beans (

Vigna angularis (Willd.)

Ohwi et Ohashi

), also known as small red

beans, are an important agricultural product in