ABSTRACT

One of the most important applications of pesticide analysis is the analysis of environmental samples. Manufacturers of pesticides must analyze wastewaters. Communities analyze air, water, and soil samples, and they find them—even in remote locations far from where they were originally used. International organizations have analyzed honeybees and their pollen to show that neonicotinoid and phenylpyrazole pesticides contribute to colony collapse disorder (CCD) [1]. The medical community and the general public are quite interested in finding the concentrations of pesticides in people, especially babies, children, and pregnant women. Even the popular press and mass media are quite interested although they can be easily confused. For example, it has been reported that children with attention deficit hyperactivity disorder (ADHD) have higher levels of pesticide metabolites in their urine and blood than children who do not [2]. Much of the mass media reported that this showed that pesticides can cause ADHD even though a principal rule of logic is that correlation does not imply causality. Just because two things are correlated, it tells us nothing about which 290one is the cause and which is the effect or if they both have the same cause. For example, it is just as likely that ADHD indirectly causes elevated levels of pesticides. Concerned, loving parents of children who have behavioral disorders (such as ADHD and autism spectral disorders) may be less likely to take their children to restaurants where they have to sit still and consume foods with high caloric, saturated fat, and sugar contents (but all low in pesticides) than “normal” children who consume the typical American diet. Instead, such parents might be more likely to feed their children healthy fruits and vegetables that do have some human-made pesticides in them. Some parents may even realize that 99.9% of the pesticides that we consume in our diets are “natural” and not made by humans [3]. Still, pesticides may help cause not just ADHD, but also autism spectral disorders [4] and autoimmune diseases [5]. It should be noted that modern medicine is becoming a fusion of traditional and Western medicine. That is, complex problems (such as autoimmune diseases) have complex causes. Seldom is there a single cause or a single cure for many diseases [5]. So there is a trend to increase the analysis of environmental samples and inform the public about them. There is also a trend to analyze samples from remote regions, to show that pollution can spread across the globe. As for sample preparation, the QuEChERS method (quick, easy, cheap, effective, rugged, and safe) has become quite popular for many food samples [6]. However, solid phase extraction (SPE) is the most commonly used method for preparing relatively clean water samples for analysis. Still, many others have started using direct injection with no sample preparation or enrichment of analytes because modern tandem mass spectrometers can provide excellent sensitivity (0.1 μg/L) in the multiple-reaction monitoring mode [7]. Another approach is to use standard addition, but it is often considered to be labor-intensive because several aliquots of each sample must have standards added to them. So one group has developed an automated standard addition method for the determination of 29 polar pesticide metabolites in wastewater and groundwater [8]. To help automate analysis, 96-well plates made from polytetrafluoroethylene coated with solid phase microextraction (SPME) fibers were used to analyze cucumbers for pesticides [9]. In the next sections, sample preparation for determining pesticides in water, air, sludge, and soil will be discussed.