Sociedade Brasileira de Espectrometria de Massas – BrMASS
The use of Easy Ambient Sonic-Spray ionization mass
spectrometry (EASI-MS), in the structural elucidation of
degradation products from technical grade pesticide
Andrea F. Machado1,2, Nicolas Schwab2, Marcos N. Eberlin2
[email protected], [email protected], [email protected]
1
2
Bioensaios Análises e Consultoria Ambiental.
Thomson Mass Spectrometry Laboratory, UNICAMP.
As a general principle for the same active substance the level of hazard posed for
health and environmental protection must be comparable for different sources of
technical material. In an equivalence studies, the active ingredient (a.i.) content and
the impurities, which might be present as a result of the manufactured process of
technical grade products, have been determined. The quali-quantitative composition of
pesticides is accessed in order to characterize the manufacturing site. This study is
needed to register products by equivalence in Brazil and worldwide. Recently, a set of
techniques known collective as ambient ionization mass spectrometric (EASI-MS)
techniques have been developed to evaluate degradation products in drugs. The main
aim of this study was to evaluate the impurities and degradation products of the
pesticide Nicosulfuron technical grade by EASI-MS.
Stress studies were carried out under hydrolysis (acid and base) and oxidation
conditions. The product solution was subjected to forced degradation under acidic and
basic by adding 0.1N HCl and 0.1N NaOH at room temperature for 24 h. The pesticide
concentration was 1 mg ml−1. Oxidative stress studies were carried out at room
temperature for 24 h in 3% H2O2. All solutions were diluted 10 times with ultrapure
water before analysis. The analyses were performed in a mass spectrometer (LCMS2010EV Shimadzu Corp., Japan) equipped with a home-made EASI.
The analysis was performed in the pesticide solution before and after stress. In the
unreacted pesticide solution analyses was possible to elucidate three impurities, these
impurities are from the manufacturing process. In the acid conditions beyond a.i. were
observed three impurities, where two of them were found in the product unreacted. In
the basic conditions was not observed the a.i., four degradation products was found,
these products are different from those elucidated in the acid conditions. There was
insignificant degradation in oxidative stress.
As for drugs, the EASI-MS technique proved to be very applicable in the
characterization of pesticide products. This fact makes the elucidation of degradation
products and impurities from raw material (production process), very fast and reliable.
Thus assisting critical steps control of the manufacturing process by knowing of
possible impurities that could be formed during synthesis.
[1] EUROPEAN COMMISSION. Health & Consumer Protection Directorate-General. Guidance
Document On The Assessment Of The Equivalence Of Technical Materials Of Substances
Regulated Under Council Directive 91/414/EEC. – SANCO/10597/2003-ver.9. 2011.
[2] Eberlin, M. N.et al. Journal of Mass Spectrometry. Drug Degradation Monitoring by Easy
Ambient Sonic-Spray Ionization Mass Spectrometry. 2011.
4º Congresso BrMass – 10 a 13 de Dezembro de 2011