Optimizing the ultrasonic extraction of polyphenols from mango peel and investigating the characteristics, antioxidant activity and storage stability of extract nanocapsules in maltodextrin/whey protein isolate.

In this study, the extraction and nanoencapsulation of mango peel extract (MPE) were investigated to enhance its stability and preserve its antioxidant properties. Initially, using the central composite design (CCD)-response surface methodology (RSM), optimal conditions for the extraction of MPE via an ultrasonic system were determined to be a temperature of 10.53 °C, a time of 34.35 min, and an ethanol concentration of 26.62 %. Subsequently, the extracted extract was spray-dried and nanoencapsulated using three types of coatings: maltodextrin, whey protein isolate (WPI), and their combination. The results showed that nanoencapsulation led to a significant improvement in the stability of phenolic compounds in the extract during storage compared to free extract. Furthermore, capsules prepared with the combined coating exhibited the highest levels of phenolic compounds and antioxidant activity. Therefore, it can be concluded that nanoencapsulation can serve as an effective method for preserving the bioactive properties of MPE.

Bromelain-loaded nanocomposites decrease inflammatory and cytotoxicity effects of gliadin on Caco-2 cells and peripheral blood mononuclear cells of celiac patients.

Enzyme therapy can be an appropriate treatment option for celiac disease (CeD). Here, we developed Bromelain-Loaded Nanocomposites (BLNCs) to improve the stability and retention of bromelain enzyme activity. After the characterization of BLNCs, the cytotoxicity of BLNCs was determined on the Caco-2 cell line. The effect of BLNCs on gliadin degradation and the production of pro-inflammatory cytokines and anti-inflammatory molecules in peripheral blood mononuclear cells (PBMCs) obtained from celiac patients were assessed. Furthermore, the expression of CXCR3 and CCR5 genes was measured in CaCo-2 cells treated with gliadin, gliadin-digested with BLNCs, and bromelain. Our study demonstrated that the Bromelain entrapment efficiency in these nanoparticles was acceptable, and BLNCs have no toxic effect on cells. SDS-PAGE confirmed the digestion effect of bromelain released from nanocomposites. When Caco-2 cells were treated with gliadin digested by free bromelain and BLNCs, the expression of CXCR3 and CCR5 genes was significantly decreased. PBMCs of celiac patients treated with Bromelain and BLNCs decreased inflammatory cytokines (IL-1ß, IL-6, TNF-α, and IFN-γ) production compared to untreated PBMCs. This treatment also increased IL-10 and CTLA-4 in PBMCs of CeD patients. According to the promising results of this study, we can hope for the therapeutic potential of BLNCs for CeD.

An Experimental Study on The Oxidative Status and Inflammatory Levels of A Rat Model of Polycystic Ovary Syndrome Induced by Letrozole and A New High-Fat Diet.

BACKGROUND: Although there are numerous animal models of polycystic ovary syndrome (PCOS), they often fail to accurately replicate the reproductive and metabolic phenotypes associated with PCOS. The objective of this study is to assess oxidative status and inflammatory levels in a rat model of PCOS subjected to a new high-fat diet (HFD) in combination with letrozole. MATERIALS AND METHODS: In this experimental study, mature, six-week-old female Sprague-Dawley rats (n=20) were divided into four groups: control (standard diet); letrozole (letrozole plus a standard diet); HFD; and letrozole+HFD. After 16 weeks, the rats underwent vaginal smear analysis, measurement of hormonal and lipid profiles, and an oral glucose tolerance test (OGTT). Ovarian tissue morphology, oxidative parameters, and inflammatory status were evaluated. RESULTS: The experimental groups exhibited anoestrus profiles in the vaginal smears and abnormal ovarian morphology, which was not observed in the control group. Steroid hormone levels were significantly higher in the letrozole+HFD group compared to the other groups (P=0.00). The experimental groups also showed abnormal glucose levels and lipid metabolism. The relative expression levels of inflammatory genes were significantly elevated in the experimental groups compared to the control group (P=0.00), and the letrozole+HFD group exhibited the highest expression level (P=0.00). The HFD, letrozole, and letrozole+HFD groups demonstrated significantly increased levels of malondialdehyde (MDA) and reactive oxygen species (ROS), while the levels of enzymatic antioxidants were significantly reduced compared to the control group (P=0.00). CONCLUSION: The combination of a new HFD and letrozole treatment induces inflammation and oxidative stress (OS) in a rat model of PCOS. This model accurately exhibits abnormal metabolic phenotypes and disruptions in hormonal profiles associated with PCOS.

Molecular imprinting of miR-559 on a peptide-immobilized poly L-DOPA/silica core-shell and in vitro investigating its effects on HER2-positive breast cancer cells.

In a significant percentage of breast cancers, increased expression of the HER2 receptor is seen and is associated with the spread and worsening of the disease. This research aims to investigate the effect of miR-559 (which targets HER2 mRNA) on SKBR3 breast cancer cells and the possibility of their effective delivery with polymeric nanoparticles and tumor-targeting peptides. L-DOPA monomers were polymerized on the surface of silica nanoparticles in the presence of miR-559 (as a molecular template for molecular imprinting) then an anti-HER2 peptide coupled to the surface of these polymeric nanocomposites (miR-NC-NL2), and the effects of this construct against a HER2-positive breast cancer cells (SKBR3 cells) investigated in vitro conditions. The results showed that miR-NC-NL2 is selective for HER2-positive cells and delivers the miR-559 to them in a targeted manner. miR-NC-NL2 decreased the proliferation of SKBR3 cells and reduced the expression and production of HER2 protein in these cells. Effective and targeted delivery of miR-559 to HER2-positive cancer cells by the miR-NC-NL2 promises the therapeutic potential of this nascent structure based on its inhibitory effect on cancer growth and progression. Of course, animal experiments require a better understanding of this structure's anti-tumor effects.

Synergistic Effect Evaluation of Magnetotherapy and a Cationic-Magnetic Nanocomposite Loaded with Doxorubicin for Targeted Drug Delivery to Breast Adenocarcinoma.

This work investigates the synergistic effect of magnetotherapy and a novel cationic-magnetic drug delivery system on inhibiting breast cancer cell growth and other tissues. First, super-paramagnetic magnetite (Fe3O4) nanoparticles were coated with doxorubicin-imprinted poly(methacrylic acid-co-diallyl dimethylammonium chloride) [Fe3O4/poly(MAA-DDA)]. The cationic-magnetic nanocomposite (CMC) was characterized using XRD, FT-IR, VSM, TGA, TEM, FESEM, EDS, DLS, and BET. In vitro analyses, including drug release kinetics, cytotoxicity, and hemolytic assays, confirmed this novel CMC's good drug release profile and biocompatibility. Finally, in vivo experiments on BALB/c mice were designed to evaluate the synergistic effect of magnetotherapy on targeted drug delivery using the CMC. In vivo fluorescence imaging evaluated the drug distribution in different tissues of mice. Tumor volume evaluation demonstrated the efficiency of the CMC and magnetotherapy in preventing tumor growth; the two techniques significantly reduced tumor volume. Histopathological analysis proved that applying magnetotherapy in conjunction with the cationic-magnetic drug delivery system significantly prevented tumor cell proliferation and increased apoptosis with limited impact on other tissues. Also, Dox and Fe concentrations in different tissues confirmed the efficient drug delivery to tumor cells.

The effects of nano-zinc oxide morphology on functional and antibacterial properties of tapioca starch bionanocomposite.

The purpose of this study was to evaluate the effect of nano-zinc oxide (ZnO-N) morphology on the functional and antimicrobial properties of tapioca starch films. For this reason, nanosphere (ZnO-ns), nanorod (ZnO-nr), and nanoparticle of ZnO (ZnO-np) at 0.5%, 1.0%, and 2.0% were added to the starch film. Then, physicochemical, mechanical, and barrier properties were evaluated. Also, UV-visible and Fourier transform infrared spectroscopy (FTIR) spectra and antibacterial activity of prepared nanocomposite films against Escherichia coli were examined. The results revealed that the ZnO-ns had the most effects on mechanical, physicochemical, and barrier properties. The highest values of the tensile strength (14.15 MPa) and Young's modulus (32.74 MPa) and the lowest values of elongation at break (10.40%) were obtained in the films containing 2% of ZnO nanosphere. In terms of UV transmission, ZnO-nr showed the most significant impact morphology. FTIR spectra indicated that interactions for all morphologies were physical interaction, and there are no chemical reactions between starch structure and nanoparticles. The antibacterial effect of the ZnO-ns was higher than that of other morphologies. In summary, ZnO-ns was the best morphology for using ZnO-N in starch-based nanocomposite films.

Targeted delivery of paclitaxel by NL2 peptide-functionalized on core-shell LaVO4: Eu3@ poly (levodopa) luminescent nanoparticles.

Targeted drug delivery enhances drug efficiency and selectivity without affecting normal cells. Luminescent nanoparticles can be used for tumor imaging as well as selective tumor targeting for drug delivery. In this research, LaVO4 :Eu3+ was synthesized, the luminescent nanocrystal was coated by surface polymerization of levodopa in the presence of Paclitaxel (PTX), and then NL2 peptide was coupled on the surface of polymer-coated luminescent nanoparticles. Next, the capability of the modified drug was examined by in vitro and in vivo experiments. MTT assay on SK-BR-3 cell line (as breast cancer cells) and fluorescent microscopy results indicate that this modification decreases significantly drug toxicity and increases its selectivity. In addition, in vivo experiments confirm more capability of the NL2-functionalized nanocomposite for reducing tumor size, drug distribution in the body, and more aggregation of PTX in tumor tissue. Overall, it is concluded that tumor imaging is possible using luminescent LaVO4 :Eu3+ core and NL2 peptide increases significantly the specificity of PTX in combination with a functionalized luminescent polymeric carrier.

In Vitro Targeting of NL2 Peptide Bounded on Poly L-DOPA Coated Graphene Quantum Dot.

Chemotherapy using drug delivery systems (DDS) can target cancer cells selectively and without affecting normal cells. In this paper, NL2 peptide as a tumor targeted peptide was bonded on the surface of poly 3,4-Dihydroxy-L-phenylalanine (Poly L-DOPA) graphene quantum dots (GQD), which was imprinted by Doxorubicin (DOX). The synthesized nanocomposite was characterized by Fourier-transform infrared spectroscopy (FTIR) and particle size was determined by dynamic light scattering (DLS) and Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). DOX release from synthesized nano-composite was investigated spectrophotometrically. Also, the toxicity and selectivity of NL2-GQD-NC on SK-BR-3 cell line were evaluated. FTIR and DLS experiment confirm the successful synthesis of Poly L-DOPA coated graphene quantum dots and their uniform particles. In vitro studies have shown that NL2-GQD-NC attached more to SK-BR-3 cells than NL2-free nanocomposites (GQD-NC). After attaching the cells could be imaged due to the presence of GQD particles and DOX release was accomplished in the tumor cells.

The effect of hydroalcoholic extract of Ziziphora clinopodioides L. on spatial memory and neuronal density of hippocampal CA1 region in rats with sporadic Alzheimer's disease.

OBJECTIVE: Alzheimer's disease is a neurodegenerative disorder associated with gradual loss of cognitive and memory abilities. It was shown that the hippocampus is one of the first structures in the brain that is affected by the disease. Ziziphora clinopodioides (Z. clinopodioides) is a member of Lamiaceae family and contains various substances. MATERIALS AND METHODS: In this experimental study, 72 adult male Wistar rats were used for behavioral and histopathologic studies. They were divided into nine groups included: control, negative control (Alzheimer), positive control (Alzheimer's treated with rivastigmine), aCSF (artificial cerebrospinal fluid) + ziziphora extract with doses of 200,400, and 600 mg/kg, and STZ (stereptozotocine)+ziziphora extract in 200,400,600 mg/kg doses. The injury was created with bilaterally intraventricular injection. The spatial memory was studied by passive avoidance test and neuronal density was evaluated by dissector method. To examine the histopathological lesions, Congo red and toluidine blue staining were done. Data were analyzed by ANOVA Minitab software. RESULTS: The memory index (neuronal density and passive avoidance test results) showed a significant decrease in negative control group compared to control (p≤0.001). Treatment with the hydroalcoholic extract at the doses of 400 and 600 mg/kg showed a significant increase in memory index in rats with Alzheimer's disease (p≤0.001). The effect of 200 mg/kg extract was not significantly different from that of the negative control group. The results of histological analysis indicated beta-amyloid plaques formation in the control group as compared to the negative control group while treatment with the extract at the doses of 400 and 600 mg/kg, significantly reduced beta-amyloid plaques formation. CONCLUSION: These findings suggest that the extract of Z. clinopodioides can improve Alzheimer's condition and alleviate memory and histopathologic damages; also, it decreases beta-amyloid plaques and apoptosis in CA1 region of the hippocampus.

Assessment of novel core-shell Fe3O4@poly l­DOPA nanoparticles for targeted Taxol® delivery to breast tumor in a mouse model.

Drug delivery systems using nanoparticles can deliver to tumor cells without affecting normal cells. In this study, a novel well dispersed magnetic nano drug was synthesized. Thus, a selective drug delivery system was designed for potential cancer treatment. A new nanocomposite, poly 3,4­dihydroxy­l­phenylalanine/Fe3O4 (l­DOPA/Fe3O4), was synthesized and used for targeted Taxol® delivery to breast tumor in inbreed Balb/c mice model with or without magnetic field. Fe and Taxol® concentrations were measured by flame atomic absorption spectrometry and high-performance liquid chromatography, respectively. Antitumor effectiveness was investigated in terms of tumor growth features. In the presence of magnetic field, Taxol® was significantly deposited in tumor tissue in Taxol-nanocomposite-treated group. In addition, the Taxol®-nanocomposite-treated group with magnetic field showed higher antitumor efficacy than the commercial Taxol and Taxol-nanocomposite without magnetic field. The magnetic nanocomposite is promising for targeted Taxol® delivery to breast tumor in a mouse model yielding high performance.

Coating of optical fiber with a smart thermosensitive polymer for the separation of phthalate esters by solid-phase microextraction.

A solid-phase microextraction fiber was prepared by coating an optical fiber with a temperature-sensitive polymer to determine phthalate esters. N-Isopropylacrylamide and N,N'-methylenebisacrylamide were used as the monomer and the cross linker, respectively. The fabricated fiber was characterized by FTIR spectroscopy, thermogravimetric analysis, and scanning electron microscopy. During extraction, important factors such as extraction time, pH, temperature, and ionic strength were optimized. The fabricated fiber, which is firm, inexpensive, stable, and efficient, is a vital material used in solid-phase microextraction. Under optimum conditions, the calibration curve was linear and in the range of 1-20 µg/L (r2  = 0.9747). The high extraction efficiency was obtained for phthalates with a detection limit of 0.12 µg/L. The fabricated fiber was successfully applied to the solid-phase micro extraction of phthalates from water samples after its extraction, followed by gas chromatography with flame ionization detection.

Synthesis of polydopamine as a new and biocompatible coating of magnetic nanoparticles for delivery of doxorubicin in mouse breast adenocarcinoma.

PURPOSE: Carrier-mediated drug delivery systems can be used to increase the intracellular concentration of drugs in cancerous cells, thereby improving drug biodistribution and minimizing unwanted side effects. This study aimed to investigate the effect of synthesized magnetic molecularly imprinted polydopamine for controlled doxorubicin (DOX) delivery in a breast adenocarcinoma model of BALB/c mice with an external magnetic field. METHODS: The synthesized DOX-imprinted polydopamine (DOX-IP) was characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The efficacy of DOX-IP in tumor growth suppression was assessed in terms of tumor growth delay, tumor doubling time, inhibition ratio, and histopathology. High-performance liquid chromatography and flame atomic absorption spectrometry were performed to investigate the drug distribution among tissues. RESULTS: The findings showed higher efficacy of DOX-IP with magnetic field in suppressing tumor growth than free DOX and DOX-IP without magnetic field. Significantly high DOX concentration in tumor tissue was found in the DOX-IP group with magnetic field. CONCLUSION: Magnetic DOX-IP demonstrates effective tumor-targeted drug delivery in a mouse model of breast cancer.

Separation of microRNA 21 as a cancer marker from glioblastoma cell line using molecularly imprinted polymer coated on silica nanoparticles.

In this study for the first time, microRNA was separated on the basis of affinity for a phase made using molecular imprinting technology. We describe the synthesis and preliminary testing of molecularly imprinted polymers for separation of the microRNA 21 from the lysate obtained from brain cancer cell line. A new molecularly imprinted polymer was synthesized using microRNA 21 and dopamine as the template and functional monomer, respectively. Dopamine was polymerized on the surface of silica nanoparticles. A control polymer, or nonimprinted polymer, was prepared under the same conditions without the use of the template molecule. The synthesized polymer was characterized by FTIR spectroscopy and its morphology was investigated by scanning electron microscopy. To compare the performance of this polymer, the results were compared with trizol extraction as a routine method of RNA extraction. The proposed method was applied for separation of microRNA 21 from cell lysate and its specificity was validated with quantitative reverse transcription polymerase chain reaction technique.

Novel molecularly-imprinted solid-phase microextraction fiber coupled with gas chromatography for analysis of furan.

This study combined a molecularly-imprinted polymer with headspace solid-phase microextraction (HS-SPME). Preparation of molecularly-imprinted polymer is not effective for volatile compounds. To overcome this limitation, pyrrole was chosen as a template for the preparation of the furan-imprinted polymer. The holes in the synthesized polymer were suitable for furan adsorption because the chemical structure of pyrrole is similar to that of furan. The extraction properties of the fiber to furan were examined using an HS-SPME device coupled with gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The effects of the extraction parameters of exposure time, sampling temperature, and salt concentration on extraction efficiency were studied. Satisfactory reproducibility was obtained for extractions from spiked water samples at RSD<7.5% (n=5). The calibration graphs were linear at 0.5-100 ng ml(-1) and the detection limit for furan was 0.042 ng ml(-1). The fabricated fiber was successfully applied for headspace extraction of furan from tap water and canned tuna as shown by GC-MS analysis.

Evaluation of magnetic nanoparticles coated by 5-fluorouracil imprinted polymer for controlled drug delivery in mouse breast cancer model.

Nanoparticles (NPs) have been extensively investigated to improve delivery efficiency of therapeutic and diagnostic agents. In this study, magnetic molecularly imprinted polymer (MIP) was synthesized by using polydopamine. Synthesized MIP was used for controlled 5-fluorouracil (5-FU) delivery in a spontaneous model of breast adenocarcinoma in Balb/c mice in the presence of an external magnetic field. Antitumor effectiveness of 5-FU imprinted polymer (5-FU-IP) was evaluated in terms of tumor-growth delay, tumor-doubling time, inhibition ratio, and histopathology. Results showed higher efficacy of 5-FU-IP in the presence of magnetic field upon suppressing tumor growth than free 5-FU and 5-FU-IP without magnetic field. The 5-FU and Fe distribution among tissues were evaluated by high-performance liquid chromatography and flame atomic absorption spectrometry, respectively. The obtained results, showed significantly deposition of 5-FU in the 5-FU-IP treated group with magnetic field. Thus, magnetic 5-FU-IP is promising for breast cancer therapy with high efficacy.

Synthesis of a new molecularly imprinted polymer for sorption of the silver ions from geological and antiseptic samples for determination by flame atomic absorption spectrometry.

A new molecularly imprinted polymer (MIP) was synthesized using methacrylic acid (functional monomer), ethylene glycol dimethacrylate (crosslinker), 2,2'-azobisisobutironitril (initiator), silver (Ag) dithizone complex (template), and chloroform (porogenic solvent). This process was a noncovalent, bulk, thermal radical-polymerization. To compare the performance of this polymer, control polymer (nonimprinted polymer) was prepared under well-defined conditions without the use of a template. Extraction experiments were performed on the MIP and a nonimprinted polymer. Then, various parameters were optimized, such as pH, time, concentration of sample, and type of eluent for elution of Ag from polymer. In addition, interfering effects were investigated on the absorption of Ag by the MIP. This polymer was used for the rapid extraction and preconcentration of Ag from an antiseptic and geological sample. Finally, the amount of Ag was measured by flame atomic absorption spectrometry after preconcentration by the synthesized MIP, and results were compared with a direct inductively coupled plasma method. The results showed high performance of this method in preconcentration of Ag.

Sensitive mercury speciation by reversed-phase column high-performance liquid chromatography with UV-visible detection after solid-phase extraction using 6-mercaptopurine and dithizone.

A highly selective and sensitive method was developed for preconcentration of inorganic and organic mercury compounds followed by reversed-phase column high-performance liquid chromatography (RP-HPLC) with UV-visible detection. The method was based on the reaction of mercury with 6-mercaptopurine and solid-phase extraction (SPE) of the complex on an octadecylsilane (C18) cartridge. The complex was then treated with ammoniacal dithizone solution, and the complexes of inorganic and organic mercury with dithizone were eluted by methanol. The speciation analysis of methylmercury (MeHg), phenylmercury (PhHg), and inorganic Hg (II) was carried out by RP-HPLC. Some experimental variables that influence the SPE and derivatization, such as pH, chelating and derivatizing agent concentration, and surfactant addition, were investigated. The calibration graphs of MeHg, PhHg, and Hg (II) were linear [correlation coefficient (r) > 0.999] from the detection limits (0.12, 0.16, and 0.14 ng) to 8.5, 6.0, and 6.7 ng Hg, respectively. By applying the SPE procedure, a 100-fold concentration of the sample was obtained. The procedure was applied to sea water and tuna fish samples. The method's accuracy was investigated by using tuna fish certified reference material BCR 464 and by spiking the samples with different amounts of MeHg, PhHg, and Hg (II). The average recoveries of MeHg, PhHg, and Hg (II) from spiked samples (0.1-2.0 microg/L Hg) were 96 +/- 4, 98 +/- 3, and 104 +/- 4%, respectively.

Separation and preconcentration of Ag(I) in aqueous samples by flotation as an ion-associate using iodide and ferroin followed the determination by flame atomic absorption spectrometry.

A simple method for separation/preconcentration and determination of Ag(I) in aqueous samples is described. The method is based on formation of an ion-associate between Ag(I)-iodide complex and ferroin, which can be floated at the interface of the aqueous/n-heptane phases. The flotation process was carried out using 500-ml aliquot of the aqueous solution and the floated layer was dissolved in 5 ml of 1 M HNO3 containing methanol (50% v/v) as the solvent. The Ag(I) content was then determined by flame atomic absorption spectrometry (FAAS). The method so could be considered as an enrichment process, was achieved to a quantitative feature, when the pH of the solution was adjusted to 4 and the concentrations of iodide and ferroin were about 3.2 x 10(-4) M and 6.25 x 10(-5) M, respectively. The LOD and RSD (n = 7) were obtained 1.0 x 10(-8) M and 2.4%, respectively. It was found that a large number of cations and anions even at high considerably foreign ion/Ag(I) ratios were not interfered. The method was applied satisfactorily to recovery of Ag(I) from different aqueous samples.

Solid-phase extraction and spectrophotometric determination of mercury with 6-mercaptopurine in environmental samples.

A highly selective, sensitive and rapid method for the determination of trace amounts of inorganic mercury based on the reaction of Hg (II) with 6-mercaptopurine and the solid phase extraction of the complex on C18 membrane disks was developed. The 6-mercaptopurine selectively reacts with Hg (II) to form a complex in the pH range of 5-8. This complex was preconcentrated by solid phase extraction with C18 disks. An enrichment factor of 100 was achieved. The molar absorptivity of the complex is 0.26 x 10(-6) L. mol(-1) cm(-1) measured at 315 nm. The Beer's law is obeyed in the concentration range of 0.002-0.048 microg mL(-1). The relative standard deviation for eleven-replicated measurement of 0.04 microg mL(-1) is 1.5 %. The detection limit is 0.001 microg mL(-1) in the water samples. The advantage of the method is that the determination of Hg (II) is free from interference of almost all the cations and anions found in environment and wastewater samples. The determination of Hg (II) in water samples of different origins and marine sediment were carried out by the present method and cold vapor atomic absorption spectrometry (CVAAS). Also the method's accuracy was investigated by using SRM 2709. The obtained results by the present procedure were in good agreement with those of the CVAAS and certified value, so that the applicability of the proposed method was confirmed for the real samples.

Methylmercury determination in biological samples using electrothermal atomic absorption spectrometry after acid leaching extraction.

An efficient and sensitive method for the determination of methylmercury in biological samples was developed based on acid leaching extraction of methylmercury into toluene. Methylmercury in the organic phase was determined by electrothermal atomic absorption spectrometry (ETAAS). The methylmercury signal was enhanced and the reproducibility increased by formation of certain complexes and addition of Pd-DDC modifier. The complex of methylmercury with DDC produced the optimum analytical signal in terms of sensitivity and reproducibility compared to complexes with dithizone, cysteine, 1,10-phenanthroline, and diethyldithiocarbamate. Method performance was optimized by modifying parameters such as temperature of mineralization, atomization, and gas flow rate. The limit of detection for methylmercury determination was 0.015 mug g(-1) and the RSD of the whole procedure was 12% for human teeth samples (n=5) and 15.8% for hair samples (n=5). The method's accuracy was investigated by using NIES-13 and by spiking the samples with different amounts of methylmercury. The results were in good agreement with the certified values and the recoveries were 88-95%.