Human Sex Hormone Disrupting Effects of New Flame Retardants and Their Interactions with Polychlorinated Biphenyls, Polybrominated Diphenyl Ethers, a Case Study in South China.

Even though sex hormone disrupting effects of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are widely understood, similar effects associated with new flame retardants (NFRs) have not been so well studied. This study aimed to explore the sex hormone disruption of NFRs and their interactions with PCBs and PBDEs through the conduct of an ecological study in an e-waste dismantling and control region in South China. Questionnaires and blood samples were collected from local adult residents. Results of generalized additive model and linear regression analyses indicate that several species of NFRs showed similar disrupting effects with PBDE congeners on female follicle-stimulating hormone (FSH) and male testosterone. Judged by the curved shape and statistical significance, ΣNFR (sum of 8 species of NFRs) showed stronger disrupting effects on male testosterone and female FSH compared to ΣPBDE (sum of 13 congeners of PBDEs). The interactions induced by NFRs complicated the original sex hormone disruption led by PCBs and PBDEs. The disrupting effects and interactions induced by NFRs decreased female FSH levels in the exposed group. Comprehensive evaluation is needed to provide the evidence base for judging the health risks arising from the increased usage of NFRs.

Determination of aminophenols and phenol in hair colorants by ultrasound-assisted solid-phase dispersion extraction coupled with ion chromatography.

A simple and reliable ultrasound-assisted solid-phase dispersion extraction coupled with ion chromatography was developed for the determination of aminophenols and phenol. The highly viscous hair colorant was dispersed in solvents using anhydrous sodium sulfite having dual functions of dispersant and antioxidant. The use of anhydrous sodium sulfite did not change the sample volume because it could completely dissolve in solution after matrix dispersion. The extraction and cleanup were combined in one single step for simplifying operation. The extraction process could be rapidly accomplished within 9 min with high sample throughput under the synergistic effects of vibration, ultrasound, and heating. Satisfactory linearity was observed with correlation coefficients higher than 0.9992, and the limits of detection varied from 0.02 to 0.09 mg/L. The applicability of the proposed method was demonstrated by measuring the concentrations of aminophenols and phenol in 32 different commercial hair color products. The recoveries ranged from 86.4-101.2% with the relative standard deviations in the range of 0.52-4.3%. The method offers an attractive alternative for the analysis of trace phenols in complex matrices.

Microwave-assisted dispersive liquid-liquid microextraction coupling to solidification of floating organic droplet for colorants analysis in selected cosmetics by liquid chromatography.

A convenient and rapid method was developed for determination of fourteen colorants in selected cosmetics based on microwave-assisted dispersive liquid-liquid microextraction (MA-DLLME) using solidification of the floating organic droplet (SFOD) as a clean-up step followed by high-performance liquid chromatography diode array detection (HPLC-DAD). DLLME was performed in a microwave device for reducing manual operations and facilitating rapid extraction equilibrium, resulting in high sample throughput and good extraction efficiency. Matrix effects could be effectively eliminated by SFOD technique. Various parameters affecting the extraction efficiency were optimized by multi-response surface methodology. The limits of detection and quantification were 0.25-3.2 mg kg-1 and 0.85-11.0 mg kg-1, respectively. The recoveries ranged from 90.2% to 106.1% with relative standard deviations of 0.30-3.1%. The method was successfully applied to the analysis of cosmetics, in which all the colorants could be quantified, and their median values ranged from 4.94 to 591 mg kg-1 for seventy-two lipsticks, and from 7.70 to 1.73 × 103 mg kg-1 for fifty eye shadows, respectively. The proposed protocol could achieve batch preparation of samples and avoid measurement errors from the obvious volume reduction of the recovered extract, and it could serve as a powerful tool for high-throughput analysis of multiple colorants in complex samples.

New oxidant used for the post-column derivatization determination of Malachite Green and Leucomalachite Green residues in cultured aquatic products by high-performance liquid chromatography.

With a new oxidant for post-column chemical derivation, a novel approach was developed for the determination of Malachite Green (MG) and Leucomalachite Green (LMG) in fish by high-performance liquid chromatography (HPLC). A C(8) column was used for separation, and elution was performed with a pH 2.5 phosphate buffer (0.02 mol L(-1)) containing 40% acetonitrile. When the eluate was combined with 3.0 x 10(-4) mol L(-1) iodine solution, LMG was converted to MG and detected at 618 nm after post-column derivatization. The recoveries of MG and LMG were ranged from 67.3% to 73.9% and 84.7% to 92.1%, respectively, which were obtained by measuring the amount of MG and LMG in the samples with solvent calibration curve. The decision limit (CCalpha) and the detection capability (CCbeta) obtained for MG and LMG were in the range of 0.10-0.17 and 0.13-0.23 microg kg(-1) in grass carp, shrimp and shellfish. This method appeared suitable for the control of MG and LMG residues in aquatic products.

[A method for determination of volatile organic compounds in drinking water by purge and trap in combination with gas chromatograph/mass spectrometry].

OBJECTIVE: To establish a method of purge and trap in combination with gas chromatograph/mass spectrometry(P and T-GC/MS) for the rapid determination of minimum multi-mixture of volatile organic compounds (VOCs) in drinking water simultaneously. METHODS: The experimental conditions of P and T, such as desorption temperature, desorption time, the type of the trap and the analytical conditions of GC were optimized. 54 VOCs in drinking water were determined by P and T-GC/MS. RESULTS: The method enjoyed a wide linear range and good precision, the method detection limit(MDL) was 0.01 - 0.5 microg/L, the average recoveries of the method was 90% - 110% and the relative standard deviation (RSD) was 1.24%-7.79%. CONCLUSION: The results showed that the method was accurate and high sensitivity and might be good for application and suitable for trace analysis of VOCs in drinking water.

[Determination of curculigoside in crude medicine Curculigo orchioides by HPLC].

OBJECTIVE: To establish a method for the determination of curculigoside in Curculigo orchioides, a species of crude medicine. METHOD: The methanol was used as the solvent of exatraction and the curculigoside was extracted from the crude medicine with the method of the ultrasonic vibration. Using Sep-Pak C18 cartridges to purify the solution, the curculigoside was detected by HPLC. Intersil ODS-3(150 mm x 4.6 mm, 5 microns) chromatographic column was used, mobile phase of methanol-water-ice acetic acid (45:80:1) and detect wavelength was set at UV 283 nm. RESULT: The average recovery was 99.2% for the determination of curculigoside, RSD = 1.7% (n = 5). The content range of the curculigoside for 6 kinds of different samples was from 0.11% to 0.35%. CONCLUSION: This method could be used to control the quality of crude medicine C. orchioides.

Gas chromatography-mass spectrometry determination of earthy-musty odorous compounds in waters by two phase hollow-fiber liquid-phase microextraction using polyvinylidene fluoride fibers.

A rapid and sensitive method for the determination of earthy-musty odorous compounds, 2-methylisoborneol, 2-isopropyl-3-methoxy pyrazine, 2,4,6-trichloroanisole, 2,3,6-trichloroanisole, and geosmin, in water samples has been developed. The method was based on coupling a new polyvinylidene fluoride (PVDF) hollow-fiber liquid-phase microextraction system with gas chromatography-mass spectrometry (GC-MS). The PVDF hollow fibers have high porosity and an enhanced solvent compatibility for extraction of the target analytes. Experimental conditions were optimized by investigating the type of extraction solvent, sample pH, sodium chloride concentration, stirring speed, extraction time, and GC-MS conditions. Under optimized conditions, the earthy-musty odorous compounds exhibited good linearity (R>0.995) in the concentration range of 6.2-250ng/L. The repeatability and reproducibility of the method were lower than 6.8% and 9.8%, respectively. The limit of detection and limit of quantification values were lower than 2.0 and 6.2ng/L, respectively. The analysis of different water samples such as tap, pond, rive and waste water indicated minimal matrix effects. Analyte recoveries for real samples spiked at different concentrations were between 84.4% and 117.5%.

Ultrasound-assisted low-density solvent dispersive liquid-liquid extraction for the determination of alkanolamines and alkylamines in cosmetics with ion chromatography.

A new one-step sample preparation technique termed ultrasound-assisted low-density solvent dispersive liquid-liquid extraction (UA-LDS-DLLE) coupled with ion chromatography (IC) was developed for the determination of three alkanolamines and two alkylamines in complex samples. Sample matrices were rapidly dissolved and dispersed to form cloudy solutions by using two solvents, where target analytes were transferred into acid solutions, while liposoluble substances were dissolved in cyclohexane. The obtained extracts could be used directly for injection analysis without any additional purification because the potential matrix interferences had been effectively eliminated in extraction process. The extraction efficiency could be markedly enhanced and the extraction could be quickly accomplished within 13 min under the synergistic effects of ultrasound radiation, vibration and heating. Various parameters influencing extraction efficiency were evaluated using orthogonal array experimental design. The extraction performance of the approach was demonstrated for the determination of target analytes in 15 commercial cosmetics covering very different matrices. Linearity ranges of 0.3-50 mg L(-1) and limits of detection varying from 0.072 to 0.12 mg L(-1) were achieved. The recoveries ranged from 86.9-108.5% with the relative standard deviations (RSDs) of 1.2-6.2%. The method was proved to be a simple and effective extraction technique that provided an attractive alternative to the analysis of trace amounts of target analytes in large numbers of cosmetics.

Rapid analysis of cyclamate in foods and beverages by gas chromatography-electron capture detector (GC-ECD).

A rapid method for determination of sodium cyclamate in foods and beverages was developed. Sodium cyclamate was converted to N,N-dichloridecyclohexylamine by reaction with sodium hypochlorite under acid condition. N,N-dichloridecyclohexylamine was subsequently extracted by n-hexane and determined by gas chromatography. Conditions such as derivatization time, the concentration of sodium hypochlorite and sulphuric acid were optimised. Amino acids, aliphatic amines, and food additives such as preservatives, dyes and sweeteners showed no interference for quantification of cyclamate. The correlation coefficient of calibration curve was 0.9993 in the range of 5.0-250mg/L. The limits of detection (LOD) and limits of quantification (LOQ) were calculated as three or ten times the signal-to-noise ratio (S/N), respectively. The LOD and LOQ for yellow wine and fruit juice were 0.05 and 0.2mg/L, respectively. The LOD and LOQ for cake and preserved fruit were 0.25 and 0.8mg/kg, respectively. The intra-day and inter-day RSD were 0.28% and 1.1% (n=5), respectively. The method was successfully applied for determination of cyclamate in yellow wine, cake, fruit juice and preserved fruit. This method was simple, fast, and sensitive. It was suitable for the determination of cyclamate in foods and beverages for safety and quality control inspections.

Ultrasound-assisted matrix solid-phase dispersive liquid extraction for the determination of intermediates in hair dyes with ion chromatography.

A novel one-step sample preparation technique called ultrasound-assisted matrix solid-phase dispersive liquid extraction was developed. After sample matrices being dispersed, target analytes were extracted into acid solutions and fat and lipin were dissolved in n-hexane while the interfering components were retained by dispersing sorbent. The extraction process could be rapidly accomplished within 9 min with high sample throughput under the synergistic effects of vibration, ultrasound action and heating. The extraction efficiency of approach was demonstrated for the determination of intermediates in commercial hair dyes with ion chromatography. Linearity ranges of 0.2-100 mg L(-1) and detection limits varying from 0.019 to 0.048 mg L(-1) were achieved. The recoveries ranged from 85.7 to 107.0% with the relative standard deviations (RSDs) of 0.31-3.7%. These results showed that the method was simple, time-saving, reliable and suitable for the routine analysis of intermediates in large numbers of hair dyes.

Optimization of a solid phase extraction and hydrophilic interaction liquid chromatography-tandem mass spectrometry method for the determination of metformin in dietary supplements and herbal medicines.

Metformin is one of the most common adulterants found in anti-diabetic dietary supplements and herbal medicines. An analytical method based on hydrophilic interaction chromatography (HILIC)/tandem mass spectrometry was developed and validated for the determination of metformin in dietary supplements and herbal medicines. Sample preparation involved solid phase extraction of the analyte using Plexa PCX cartridges, and cleanup by a primary-secondary amine (PSA) adsorbent for minimization of the matrix effect. Chromatographic separation was performed on a HILIC column using a mixture of 0.025 mol/L ammonium formate (pH 3) and acetonitrile (18:82, v/v) as the mobile phase at flow rate of 0.25 mL/min. The method was validated in four matrices (capsules, honeyed pills, tablets and oral solutions). The method had a good linear range (5-500 ng/mL), and the overall precision and accuracy ranged from 2.2% to 9.9% and 4.6% to 11.3%, respectively.

Multi-channel purge and trap system coupled with ion chromatography for the determination of alkylamines in cosmetics.

A new multi-channel purge and trap system coupled with ion chromatography for the determination of six alkylamines in cosmetics was developed. The proposed method, based on purge and trap of the volatile alkylamines, involved in a miniaturization and multi-channel integration of classical steam distillation and a simple approach for routine labs. The procedure was rapidly achieved within 10 min and the matrix interferences could be effectively eliminated. Sample pretreatment frequency was higher than 40 h(-1). The linear ranges were 0.1-15 mg L(-1) and the detection limits varied from 0.023 to 0.038 mg L(-1). This method was successfully utilized to determine the amounts of alkylamines in cosmetics with recoveries ranging from 80.3 to 105.5% and the relative standard deviations (RSDs) ranging from 0.78 to 7.5%. It was proved to be accurate, time-saving, and suitable for the determination of large numbers of cosmetics in a short time.

Aptamer-targeted magnetic nanospheres as a solid-phase extraction sorbent for determination of ochratoxin A in food samples.

A sorbent based on the aptamer for ochratoxin A was immobilized onto magnetic nanospheres (MNS) and used to develop a magnetic solid-phase extraction procedure to clean up food samples in conjunction with high-performance liquid chromatography separation and fluorescence detection. Specific retention of ochratoxin A by the sorbent was demonstrated, and the capacity of the MNS-aptamer sorbent was determined. The efficacy of this new approach was successfully evaluated through comparison with solid-phase extraction on commercial C18 cartridge. Several different food samples fortified in the range of with 2.5-50 µg/kg yielded mean recoveries from 67% to 90%, respectively. Finally, this oligosorbent was applied to the selective extraction of ochratoxin A from unfortified food samples.

[Determination of 15 volatile organic compound residues in cosmetics by headspace gas chromatography].

A headspace gas chromatography (HS-GC) method was developed for the rapid determination of multimixture of 15 residual volatile organic compounds in cosmetics. The experimental conditions of HS-GC such as headspace temperature, headspace time and the analytical conditions of GC were optimized. Cosmetic samples were extracted and cleaned-up by headspace at 60 degrees C for 30 min, determined by GC-flame ionization detector (FID) and quantified by external standard method. The 15 poisonous volatile organic compounds were separated efficiently from impurities with high sensitivity and reproducibility. The relative standard deviations (RSDs) were less than 5%, the recoveries were from 62.8%-116%, the linear range was 0.002-2.0 mg/L with a good linear correlation coefficient (r > 0.999) and the limits of detection were 0.09-0.68 mg/kg. By means of the above developed HS-GC method, 15 residual volatile organic compounds in cosmetics were detected accurately and simultaneously in a single sample injection. The method is accurate, simple, rapid, and is suitable for the trace analysis of multimixture of residual volatile organic compounds in various cosmetics.

[Simultaneous determination of ammonium and six alkylamines in cosmetics by ion chromatography].

A method for the simultaneous determination of ammonium and six alkylamines in cosmetic products by ion chromatography (IC) was developed. The sample pretreatment process and the separation resolution of chromatography were investigated. The samples were extracted by 100 mmol/L acetic acid-20% (v/v) acetonitrile solution at room temperature, and then solid phase extraction (SPE) column was used to eliminate the interferences. The influences of pH value, organic solvent and coexisted ions were investigated. The separation was carried out on IonPac CS17 (250 mm x 4 mm)analytical column and IonPac CG17 (50 mm x 4 mm)guard column using 1.5 - 15 mmol/L methanesulfonic acid and 0.5% - 5% (v/v) acetonitrile gradient elution at a flow rate of 1.0 mL/min at 24 degrees C, coupled with suppressed conductivity detector. Under the optimum conditions, a measurement could be completed less than 26 min. The linearity ranged from 0.3 to 15 mg/L, the detection limits and the quantification limits were in the ranges of 2.1 - 7.9 mg/kg and 7 - 26 mg/kg, respectively. The method was successfully employed for the determination of ammonium, methylamine, dimethylamine, trimethylamine, ethylamine, propylamine and butylamine in samples including cleaning, body lotion, skin-bleaching, sun block, marcel, hair dye and pilatory cosmetics with the recoveries of 80.2% - 109.2% and the relative standard deviations (RSDs) of 0.5% - 3.1%. The method offered high selectivity, sensitivity, and gave satisfactory results for real sample analysis.

Synthesis and characterization of a novel molecularly imprinted polymer for simultaneous extraction and determination of water-soluble and fat-soluble synthetic colorants in chilli products by solid phase extraction and high performance liquid chromatography.

A sorbent was synthesized and investigated for molecularly imprinted solid phase extraction (MISPE). Molecularly imprinted polymers (MIP) were synthesized via precipitation polymerization procedure, where 4-vinyl pyridine (4-VP) was used as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The imprinting effect of the MISPE was evaluated by elution experiments. The resulting MISPE showed high extraction selectivity to water-soluble and fat-soluble synthetic colorants. The determination of multi-residue for three kinds of water-soluble and six kinds of fat-soluble synthetic colorants in chilli products was also investigated by HPLC coupled with MISPE. The mean recoveries calculated by solvent calibration curve for water-soluble and fat-soluble synthetic colorants were from 72.1% to 95.6% for chilli spice and 72.1% to 92.3% for chilli powder. The decision limit (CCalpha) and the detection capability (CCbeta) obtained for water-soluble and fat-soluble synthetic colorants were in the range of 1.2-1.6 and 1.9-2.4 microg kg(-1) in chilli spice and chilli powder. The resulting MISPE was successfully used off-line for the determination of nine kinds of synthetic colorants in chilli products.

Determination of multi-residue for malachite green, gentian violet and their metabolites in aquatic products by high-performance liquid chromatography coupled with molecularly imprinted solid-phase extraction.

A sorbent was synthesized and investigated for molecularly imprinted solid-phase extraction (MISPE). Molecularly imprinted polymers (MIPs) were synthesized via precipitation polymerization procedure, where methacrylic acid (MAA) was used as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The imprinting effect and selectivity of the MISPE were evaluated by elution experiments. The resulting MISPE showed high extraction selectivity to malachite green, gentian violet and their metabolites, which may be caused by both the ion exchange and the hydrophobic interactions. The determination of multi-residue for malachite green, gentian violet and their metabolites in aquatic products by HPLC coupled with MISPE was also investigated. The mean recoveries calculated by solvent calibration curve for malachite green (MG), gentian violet (GV), leucomalachite green (LMG) and leucogentian violet (LGV) were from 89.8% to 99.1% for grass carp, 90.6% to 101.2% for shrimp and 91.3% to 96.3% for shellfish. The decision limit (CCalpha) and the detection capability (CCbeta) obtained for MG, GV, LMG and LGV were in the range of 0.11-0.14 and 0.19-0.24 microg kg(-1) for grass carp, shrimp and shellfish. The MISPE was successfully used off-line for the determination of MG, GV and their metabolites in aquatic products.