**5. Extraction techniques of carbamates pesticides**

The separation of pesticides is necessary from the sample before introducing into the instrument. This approach is expected to limit measuring interferences while enhancing the analyte concentration for research. Besides, the extraction method is a standard procedure that begins with releasing a preferred analyte from matrices and ends with a purification procedure, which directs to a series of stages via the analytical approach wherein a high proportion of potential interference co-extracts is eliminated using chemical or physical means [53]. Liquid-liquid extraction (LLE), solid-phase extraction (SPE), solid-phase microextraction (SPME), quick, easy, cheap, effective, rugged, and safe, microwave-assisted extraction (QuEChERS), and microwave accelerated selective Soxhlet extraction are among the extraction technologies available.

*Extraction and Identification Techniques for Quantification of Carbamate Pesticides in Fruits… DOI: http://dx.doi.org/10.5772/intechopen.102352*

#### **5.1 Liquid-liquid extraction (LLE)**

Liquid-liquid extraction (LLE) has become a standard procedure in sample preparation due to its convenience and efficacy for insecticide contamination of food [54]. However, LLE requires a lot of solvents, which is terrible for the environment compared to solventless extraction technologies like solid-phase microextraction. On the other hand, the LLE approach is poor in yield analyte concentration, laborious, and requires a significant volume of toxic organic solvents [55]. Previously, liquid-liquid extraction/low-temperature purification incorporated with HPLC-UV was applied for determining aldicarb, carbofuran, and carbaryl in water samples. The separation for the carbamates aldicarb, carbofuran, and carbaryl show a high recovery rate. Although in small amounts of material and solvent, the extraction method was selective, with a limit of detection was found 5.0 and 10.0 g L−1 [56].

#### **5.2 Solid-phase extraction (SPE)**

Solid-phase extraction (SPE) was initially presented during the 1970s, then widely accessible in 1978. At the moment, the most often used widely is SPE procedures for the pretreatment of environmental materials [55]. SPE is simpler, acceptable, and convenient than traditional LLE. Wang et al. [57] recently published an SPE technique utilizing porous organic polymers as an absorbent to extract isoprocarb, metolcarb, bassa, carbaryl, and lastly, diethofencarb, from white wine, milk, and juice before HPLC-diode array detection. The findings showed that milk and white wine samples have excellent linearity, with low detection limits for milk, white wine, and juice samples.

Earlier, Li et al. [58] used a simple one-step synthesis technique to make graphenebased magnetic nanoparticles by using MSPE to detect trace carbamate insecticides in tomatoes. Under ideal conditions, this technique has high enrichment factors, good linearities, low detection, and satisfactory spiking recoveries. The findings show that this approach was an adequate preparation and enhancement approach that may be used to extract and determine trace carbamate pesticides in complicated matrices. Besides that, Shi et al. [59] used graphene-based solid-phase extraction with ultra-HPLC-tandem mass spectrometry to analyze carbamate in ambient water samples. The LOD ranged from 0.5 to 6.9 ng L−1, with relative standard deviations of 5.54%. The graphene-packed SPE cartridge may be reused over 100 times for a typical solution after proper regeneration with no appreciable performance degradation. The target analytes' has good enrichment values, which indicate that the developed approach successfully determined carbamate pesticide residues in ambient water samples.

#### **5.3 Solid-phase microextraction (SPME)**

Solid-phase microextraction (SPME) is a technology that is a highly selective, sensitive, and solvent-free sample and is frequently used to extract volatile and semivolatile chemicals by its absorption fibers. The range of SPME coatings available, dependent on the analytes' polarity, results in high sensitivity and selectivity because of the strong coating affinity for particular analytes that build up in the environment until they reach equilibrium [60]. Zhou and Fang [61] developed a graphene-modified TiO2 nanotube array by electrodeposition utilizing a cyclic voltammetric reduction approach to detect carbamate. When utilized in TiO2 nanotube arrays for MSPE,

the combination of graphene's adsorptive solid properties and its higher extraction capabilities results in remarkable sample preconcentration performance. These results indicate that graphene-modified TiO2 nanotube arrays have a high capacity for adsorption of contaminants. The technique demonstrates a quick and efficient alternative analytical solution for detecting and quantifying carbamate in fruits and vegetables.

#### **5.4 QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction**

Quick, easy, cheap, effective, rugged, safe (QuEChERS) is a sensitive food analysis technology that has undergone numerous revisions and advancements. QuEChERS is a two-stage technology employed to detect carbamate residues in foods that includes salting-out partitioning, which involves the transition between an aqueous and an organic layer. This technique necessitates further cleaning to remove interfering chemicals by combining magnesium sulfate with various sorbents like C18, graphitized carbon black (GCB), or primary-secondary amines (PSA). It may be used to clean a variety of complex substances like food products while also allowing for a less organic solvent [62]. Due to its numerous advantages, the QuEChERS technique has gained massive attention and is widely utilized and regarded as a preferable approach for measuring toxic contaminants in foods.

Previously, Anastassiades et al. [63] introduced the QuEChERS technique to extract carbamate from food matrices by using a small quantity of acetonitrile, followed by a clean-up step employing DSPE. This method was first used to examine fruits and vegetables. Nonetheless, recent research adapted QuEChERS and used dried samples, animal-based food, cereal, milk-based products, and soil-sediment analysis [64]. The approach is based on analyte extraction in buffered acetonitrile (MeCN) and subsequent separation by salting out and d-SPE. The primary disadvantage of this technique is that the natural elements of the sample must be removed. Based on a study by Zhang et al. [65], they adopted LC-MS/MS to assess 60 different insecticide contaminants in cinnamon bark using a repeated dispersive SPE with QuEChERS.

Some studies reported that almost 54 pesticides residues were extracted and analyzed by acetonitrile. Furthermore, Reddy and Reddy [66] employed QuEChERS to extract pesticides from sunflower oil using modified charcoal to reduce fat and pigment thermal deterioration during analysis. Furthermore, according to Neufeld et al. [67], QuEChERS extraction has a high sensitivity to organophosphates and carbamates. Besides, the QuEChERS technique combined with magnetic SPE and DLLME was developed to remove pesticides from high-solid vegetable, fruit, and nectar samples [68].

#### **5.5 Microwave-assisted extraction (MAE)**

Environmental Canada pioneered microwave-assisted extraction (MAE), which is currently used in research applications and industrial settings. This approach employs microwave radiation to induce polar molecules and ions to migrate and dipoles to spin to heat solvents and assist the transfer of the target from the food matrix to the extractant [69]. According to Wang et al. [70], the significant edges of adopting MAE are reducing the time extraction, which could be assigned to the differences in the microwave and traditional heating performance. MAE also allows for on-the-fly connection to different analytical processes and the simultaneous execution of several *Extraction and Identification Techniques for Quantification of Carbamate Pesticides in Fruits… DOI: http://dx.doi.org/10.5772/intechopen.102352*

samples. A quick and straightforward analytical method based on LC-MS/MS has been established to measure carbamate residues and mycotoxins in apples using MAE simultaneously. In the recovery rate range of 70–116%, the technique displayed strong linearity with high acceptable accuracy and a lower limit of detection [71].

#### **5.6 Microwave accelerated selective Soxhlet extraction (MA-SSE)**

Microwave accelerated selective Soxhlet extraction (MA-SSE) is a technique similar to traditional Soxhlet extraction but employs microwaves to improve the procedure [72]. Although MA-SSE is fast and effective, its poor selectivity requires additional cleaning operations. Besides, a selective MA-SE approach is required due to its time-consuming and labor-intensive nature. Zhou et al. [72] employed MA-SSE as a selective extraction strategy in their investigation to detect the carbamate contaminants in ginseng. The MA-SSE extracts the sample's target analytes and interfering components using microwave-irradiated extraction solvent. After the solvent passed through the extraction container, the sorbent adsorbed the interfering elements in the solvent and collected the target analytes. Because of the effect of microwave irradiation, MA-SSE outperformed conventional extraction processes significantly. According to the findings, MA-SSE has much potential as a fast and reliable method for preparing samples to detect pesticide residue in complex matrices.

### **6. Conventional techniques for detection of carbamate pesticides**

Various techniques for identifying carbamate residues are summarized in **Table 1**.

#### **6.1 Capillary electrophoresis (CE)**

Capillary electrophoresis (CE) is a proper analytical method that could also be applied in various situations and is expected to offer several advantages, including fewer chemicals and samples, higher removal efficiency, and time efficiency. The capillary's inner diameter (50–75 m) is tiny, allowing only a limited sample volume to be injected into the system, thus limiting sensitivity detection. Due to the small volume of sample that can be injected into such a capillary system, CE has been combined with sensitive detection [81] and combined with internet-basedconcentration methods. Attig et al. [82] described a microextraction technique for selective preconcentration of N-methyl carbamate in water prior to CE analysis using temperature-controlled IL-DLPME in an alkaline buffer. Microextraction with ionic liquid and elution with a trace amount of dichloromethane was used to obtain the samples. MMWCNTs enhanced ionic liquid-analyte binding and recovery compared to using simple nanomaterials as a sorbent. Cheng et al. [83] developed a CE with amperometric detection based on a polyamide-modified carbon paste electrode to determine carbamate in alkaline water solutions. According to Zhang et al. [84], an efficient method for simultaneous determination of carbamate pesticides in vegetables included solid-phase microextraction for purification and enrichment, followed by CE separation. Standard addition recoveries of 86.1–115.8% for vegetable samples are quick and accurate. The presence of carbamates has been determined using nanomaterials such as graphene and gold nanoparticles in pesticide biosensors [85]. Direct electrodeposition of electrochemically reduced graphene oxide-gold


#### **Table 1.**

*Detection techniques of carbamate pesticides.*

nanoparticles-cyclodextrin and Prussian blue-Chitosan modified glass carbon electrodes was used to identify pesticides. Carbamate pesticides inhibit AChE activity, with malathion having a LOD of 4.14 pg mL−1 and carbaryl having a LOD of 1.15 pg mL−1.

#### **6.2 Micellar electrokinetic capillary chromatography (MEKC)**

Micellar electrokinetic capillary chromatography (MEKC), a hybrid methodology incorporating chromatographic and electrophoretic extraction principles, extends the usability of capillary electrophoretic procedures to neutral analytes. Surfactants are added to the buffer solution at quantities remarkably different from their essential micellar concentrations, producing micelles that move electrophoretically like any other charged particle. The separation is based on the differential partitioning of an analyte between two-phase systems: the moving aqueous phase and the micellar pseudo stationary phase [86]. Using MEKC with a UV-Vis detector, the best separation conditions were 20 mM phosphate buffer (pH 8.0) and 15 mM sodium dodecyl sulfate. The detecting wavelength was set at 200 nm, with a voltage of 12.5 kV supplied. Baseline separation of five pesticides took 15 minutes under these circumstances with low detection limits. This method produced high repeatability, reproducibility, separation efficiency, and a reasonable recovery rate in rice samples [87]. MEKC has evolved into an effective separation technology for neutral and ionic chemicals in complex mixtures, including a broad spectrum of analytes. MEKC is based on the separation of the micellar and aqueous phases. See et al. [88] originally described a technique for determining glyphosate and aminomethylphosphonic

*Extraction and Identification Techniques for Quantification of Carbamate Pesticides in Fruits… DOI: http://dx.doi.org/10.5772/intechopen.102352*

acid in tap and river water using a dynamic supported liquid membrane tip extraction approach followed by MEKC with capacitively linked contactless conductivity detection. Besides, Sung et al. [89] used in-line LLE surface analysis with CE to detect pesticides on solid surfaces of apples. Other research used the SPE-MEKC approach to identify trifloxystrobin, tebufenozide, and halofenozide in foods with detection limits ranging from 0.088 to 0.094 mg/kg [90]. Moreover, Santalad et al. [91] described an SPE-MEKC approach for determining the presence of six carbamate pesticides with low detection limits. Water-soluble CdTe/CdSe core-shell quantum dots were employed to enhance pesticides selective fluorescence enhancement [92]. The baseline separation took 12 minutes, and the detection limits obtained varied from 50 to 180 μg/kg [93]. DLLME coupled with sweeping in MEKC, a quick, easy, and sensitive approach for detecting certain neonicotinoid pesticides in cucumber samples has been devised. Under optimal circumstances, enrichment factors ranging from 4000 to 10,000 were obtained. The method's linearity ranged from 2.7 to 200 ng g−1 for thiacloprid, acetamiprid, and imidacloprid in cucumber samples and from 4.0 to 200 ng g−1 for imidaclothiz, with the limit of detection varied from 0.8 to 1.2 ng g−1. The new approach successfully analyzed neonicotinoid pesticides in cucumbers, promising outcomes [94].

#### **6.3 Enzyme-linked immunosorbent assay (ELISA)**

Immunochemical techniques, such as enzyme-linked immunosorbent assay (ELISA), have recently gained interest and recognition as rapid and low-cost extraction and detection procedures for pesticide compounds. Based on the antigenantibody interaction, this analytical technique can give high sensitivity and specificity (selectivity) for particular kinds of pesticides. Additionally, since it can load many samples concurrently, it enables rapid and precise assessment of pesticide residues in agricultural items prior to shipping. Indeed, the primary advantage of ELISA for identifying pesticide residues is the convenience of sample preparation methods [95]. Bellemjid et al. [96] created a rapid ELISA to detect carbamates such as carbendazim and carbofuran using synthetic compounds with acid functions linked with BSA protein and injected into rabbits with antibodies collected for the immunoanalytical test. Zhang et al. [97] used nanobody Nb316 to develop an indirect competitive enzyme-linked immunosorbent test (ELISA) to detect carbofuran in vegetable and fruit samples. A phage display platform was used to extract and characterize unique nanobodies against the pesticide carbofuran from an immunized library. The average recovery rate of spiked samples was 82.3–103.9%, comparable to the conventional UPLC-MS/MS approach.

#### **6.4 Gas chromatography-mass spectroscopy (GC-MS)**

James and Martin [98] devised the gas chromatography (GC) technology in 1952. The fundamental working concept of gas chromatography is the volatilization of the sample in the input or injector of the gas chromatograph, followed by the separation of the mixture's components in a specially designed column. Pesticide residues were recently found in Chinese liquor using gas chromatography-mass spectrometry [99]. In general, Chinese liquor is an extraction of fermented food. They are a trendy alcoholic beverage in China. In Chinese liquor, ethyl carbamate was found at a detection limit of 0.56 μg/L and a limit of quantification of 1.87 μg/L. Ethyl carbamate was also discovered in Chinese rice wine using gas chromatography-mass spectrometry [100]. According to Yao et al. [101], GC-MS detected ethyl carbamate in grain co-products. A gas chromatography-mass spectrometry assay with the limit of detection of 0.7 ng/g was developed to measure ethyl carbamate extracted from different distillers grains co-products. It was identified in all of the co-products of distillers grains examined in this investigation. The greatest concentration of ethyl carbamate was found in corn condensed distillers solubles, ranging from 1618 to 2956 ng/g. Other kinds of distillers grains co-products exhibited ethyl carbamate concentrations ranging from 17 to 917 ng/g.
