Monitoring of 2,4-dichlorophenoxyacetic Acid in Bee Products by Solid Surface Fluorescence

Summary

This work proposes the development of a new alternative methodology to traditional techniques for the control and monitoring of 2,4-dichlorophenoxycarboxylic acid in bee product samples from central and northern Argentina.

Abstract

Bee health is essential for honey production and crop pollination. Honey production can be negatively affected by the use of herbicides, as bees can come into contact with these chemicals when collecting nectar and pollen from treated plants, which can lead to honey contamination with these toxic residues. While 2,4-dichlorophenoxyacetic acid (2,4-D) is designed to control broad-leaf weeds, it can reach flowers and contaminate bees' production, potentially affecting bees' health and quality of life. For these reasons, it is important to analyze honey periodically, in order to detect the presence of herbicide residues and, if necessary, take corrective measures. This work proposes the development of a new alternative methodology to traditional techniques for the control and monitoring of 2,4-D in bee product samples from central and northern Argentina. Samples were conditioned at pH = 7.0 in the presence of the anionic surfactant sodium dodecyl sulfate (SDS), filtering the systems through blue-band filter paper as a solid support before determination by solid phase fluorescence. Under optimal working conditions, detection and quantification limits of 0.33 ng/L and 0.90 ng/L, respectively, and a linearity range of 0.90 x 10³ ng/L to 1.13 x 10³ ng/L were achieved. Among the advantages of the new method are the use of inexpensive instruments and eco-friendly solvents, low waste generation, and, consequently, its safeguarding of some principles of green chemistry.

Introduction

Bee health is essential for honey production and crop pollination. A healthy colony depends on comprehensive health management that includes proper nutrition, hygiene measures, and disease prevention and treatment. Honey production, if carried out responsibly, does not harm bees, as beekeepers only extract a small portion of the total honey, leaving reserves for the colony^1,2.

Honey production can be negatively affected by the use of herbicides, as bees can come into contact with these chemicals when collecting nectar and pollen from treated plants, which can lead to honey contamina....

Protocol

This manuscript does not contain any studies with human participants or animals performed by any of the authors.

Apparatus used
Spectrofluorimetric measurements were performed using a PC-based spectrofluorometer equipped with a 150 W xenon lamp. A sample holder was used for solid surface fluorescence (SSF) measurements. The parameters used for 2,4-D quantification were as follows: λ_em= 580 nm, using λ_ext= 555 nm (Slits 3-3), using a solid sample holder.

Sampling and sample treatment
This study on the production of honey samples produced....

Results

The results presented below indicate how the study of each of the variables that influence the general procedure, its optimization, and the optimal working conditions that were reached was approached step by step.

2,4-D spectrum characterization
2,4-D characterization was carried out by UV-Vis spectroscopy and molecular fluorescence, observing fluorescent intensity maxima at λ_em= 580 nm, using λ_ext= 555 nm (Slits 3-3; Figure 1

Discussion

The intensive use of herbicides has increased exponentially in Argentina and the rest of the world due to the need to meet the food demands of a growing population. If the use of such products is monitored appropriately, rationally, and periodically, it would not compromise the expected benefits or have negative effects on the environment as a whole. 2,4-D has been widely used worldwide, and many studies have shown that this herbicide induces alterations in non-target organisms. Therefore, continuing to evaluate the risk.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
2,4-D	Sigma-Aldrich, St. Louis, USA	49083
Acetic acid/acetate	Mallinckrodt Chemical Works
Blue Ribbon filter papers	Sigma-Aldrich, St. Louis, USA	WHA1001929	2-5 μm pore size and 12.5 cm diameter
Cellulose acetate membrane	Sigma-Aldrich, St. Louis, USA		0.45 μm pore size and 47 mm
Hexadecyltrimethylammonium bromide (HTAB)	Sigma-Aldrich, St. Louis, USA	H5882
hydrochloric acid	Sigma-Aldrich, St. Louis, USA	1.09063
Immobilon (+) membranes	Millipore, Sao Paulo, Brazil	HATF04700	0.45 μm pore size and 47 mm
Mixed esters membranes	Sigma-Aldrich, St. Louis, USA		0.45 μm pore size and 47 mm
Nylon membranes	Millipore, Sao Paulo, Brazil	Z290793	0.45 μm pore size and 47 mm diameter
pHmeter (Orion Expandable Ion Analyzer, )	Orion Research, Cambridge, MA, USA	Model EA 94.
Potassium dihydrophosphate	Biopack, Buenos Aires, Argentina	2000168900
Potassium phthalate acid	Merk &Co., Inc
Sodium Dodecyl Sulfate	Sigma-Aldrich, St. Louis, USA	11667289001
Sodium hydroxide	Sigma-Aldrich, St. Louis, USA	S2770
Sodium tetraborate	Sigma-Aldrich, St. Louis, USA	221732
Spectrofluorimetric	Shimadzu	RF-5301	equipped with a 150 W Xenon lamp and 1.00 cm quartz cells
Tris-(hydroxymethyl)-aminomethane	Sigma-Aldrich, St. Louis, USA	77-86-1