Simple analytical method for determination of pesticide residues in human serum by liquid chromatography tandem mass spectrometry

A Review on Spike and Recovery Method in Analytical Method Development and Validation

In multidisciplinary science, Analytical approaches based on spike and recovery (SAR) play a substantial role in analytical testing. The spike and recovery method is an important technique for analyzing and accessing the accuracy of analytical methods. The goal of this review seeks to provide clarity on the role of SAR methods in the forensic science discipline. Recent literature has been searched from numerous databases like Google, Web of Sciences, Scopus, PubMed, Google Scholar, and SciFinder. Websites like Science Direct are critically explored to gather scientific reports related to SAR utility. This review discusses the applications and current role of the SAR methods in Forensic Toxicology. It is suggested as one of the major parameters in the validation of the analytical method. SAR methodology is extremely important for the identification and quantitation of analytes in the sample matrix. Moreover, the extension of SAR methods to any scientific discipline is equally important for quality assurance. All relevant processes like method development and its optimization, quality control, and assurance rely on SAR-based studies. However, the method requires better apprehension and needs to be utilized using standard guidelines.

Liquid chromatography tandem mass spectrometry for the determination of nine insecticides and fungicides in human postmortem blood and urine

Pesticide poisoning is a common occurrence due to their widespread use, easy access and high toxicity even in small concentrations. The most common poisoning fatalities have been observed due to exposure to organophosphates, carbamates and neonicotinoids, thus development of a method for the rapid determination of these compounds in blood and urine is of great importance for clinical and toxicology laboratories. A simple, fast and reliable method was developed for the determination of 9 pesticides in blood and urine using HPLC-MS/MS instrumentation. In order to find the most suitable sample pretreatment technique, three different sample preparation procedures: SPE, protein precipitation and QuEChERS were compared. The final optimized analytical method was fully validated with the values of parameters such as calibration linearity, accuracy, precision, recovery, matrix effect and stability being acceptable. The method proved reliable, accurate, robust and sensitive and was successfully applied for the quantitation of pesticides in three postmortem cases of pesticides poisoning.

Method development for simultaneous determination of polar and nonpolar pesticides in surface water by low-temperature partitioning extraction (LTPE) followed by HPLC-ESI-MS/MS

During this research, chemometric approaches were applied for optimization of the low-temperature partitioning extraction (LTPE) for the simultaneous analysis of the pesticides: acephate, difenoconazole, fenamidone, fluazifop, fluazinam, methamidophos, and thiamethoxam from surface water samples and determination by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. It was used the 2³ full factorial and the Doehlert experimental designs. The extraction technique was optimized by evaluating the effects of the three variables: sample pH, ionic strength (addition of Na₂HPO₄), and organic solvent volume. Considering the interest to find an optimal condition for all analytes simultaneously, the best extraction parameters found were as follows: pH = 5.33, concentration of Na₂HPO₄ = 0.0088 mol L^-1 and organic phase volume = 4.5 mL. The optimized methodology showed LOD and LOQ levels from 0.33 to 8.13 ng L^-1 and from 1.09 to 26.84 ng L^-1, respectively. The recovery values ranged from 38.37 and 99.83% and the RSD values varied from 2.33 to 18.92%. The method was applied to surface water analysis sampled in areas with intensive agricultural practices in Ouro Branco City, Minas Gerais, Brazil. The difenoconazole was detected in concentrations between 12.53 and 94.76 ng L^-1.

Synthesis and Application of Novel Molecularly Imprinted Solid Phase Extraction Materials Based on Carbon Nanotubes for Determination of Carbofuran in Human Serum by High Performance Liquid Chromatography

Novel molecularly imprinted polymers (MIPs) based on multiwalled carbon nanotubes (MWNTs) were synthesized using carbofuran as template, methacrylic acid as functional monomer, and trimethylolpropane trimethacrylate as cross-liking agent, respectively. Characterization results showed that the carbofuran MIPs have been successfully grafted onto the surface of MWNTs as a thin layer with high stability. The results of adsorption dynamics indicated that the synthesized MWNT-MIPs displayed a biphase adsorption profile and good selective recognition to carbofuran with equilibrium adsorption of 106.2 mg/g. The MWNTs-MIPs synthesized were further applied as the adsorbent material of solid-phase extraction (SPE) for the pretreatment of carbofuran in human serum, analyzed using high performance liquid chromatograph (HPLC). The recoveries obtained ranged from 89.0 ± 4.8 to 93.6 ± 3.2, showing that the MWNTs-MIPs-SPE system developed have specific recognition toward carbofuran. Results above indicated that the proposed system filled with synthesized MWNTs-MIPs provided a fast and selective extraction of carbofuran in serum.

Determination of insecticide residues and their adverse effects on blood profile of occupationally exposed individuals

Insecticides, essential for crop protection measures, leave behind several toxic residues that can result in a series of human health disorders. Therefore, this study was planned for the determination of residues and adverse effects of insecticides in blood samples of sprayers, pesticide-industry workers and controls by using blood parameters of these individuals as biomarkers. Optimized analytical methods using GC-MS and HPLC for the simultaneous detection of 22 currently used insecticides were adopted. Eight of twenty-seven (22.22%) sprayers' blood samples were found positive for five different insecticides. Eleven of twenty-seven (40.74%) pesticide-industry workers were found positive for eight different insecticides. The blood samples of both the exposed groups, sprayers and industry workers had significantly (P < 0.001; Mann-Whitney U-tests) low hemoglobin-Hb concentrations (12.17 ± 2.13 and 12.22 ± 2.37 g/dl respectively) than the average value of the control group with 14.23 ± 2.37 g/dl. The erythrocyte sedimentation rates (ESRs) in sprayers and insecticide industry workers (28.78 ± 20.72 and 28.17 ± 25.14 mm/1st h respectively) were greater significantly (P < 0.001; Mann-Whitney U test) than the control blood samples (9.53 ± 3.34 mm/1st h). These results indicate that the exposed individuals have experienced significant hemotoxic effects during insecticide exposure. The study also predicts the risk to exposed individuals in developing countries like Pakistan and demands realization of safety measures to prevent such dangerous effects of pesticide exposures.

Monitoring of systemic exposure to plant protection products and DNA damage in orchard workers

The systemic exposure of plum tree growers and operators to plant protection products (PPPs) and effects on DNA were assessed. Specifically, a GC-MS/MS method was developed and validated for the analysis of serum samples for the presence of seven active substances of PPPs. The analytical results verified the presence of myclobutanil, propargite, cypermethrin and deltamethrin in 7 out of 19 serum samples. The incidence of DNA damage was monitored using the single cell electrophoresis assay (comet assay). A paired Student's t-test revealed a statistically significant increase of SSBs in the blood samples collected at the end of the cropping period as compared to the samples collected from the same subjects before the start of PPPs application period. Moreover, the group of seven subjects with detectable serum pesticides levels revealed statistically significant increase of SSBs as compared to the group of subjects with no detectable PPP levels. The results of the present study demonstrate that the agriculture workers may exhibit detectable level of systemic exposure to the applied PPPs which are correlated to increased DNA damage during the cultivation period.