Changes in Gel Characteristics, Rheological Properties, and Water Migration of PSE Meat Myofibrillar Proteins with Different Amounts of Sodium Bicarbonate.

The changes in the gel and rheological properties and water-holding capacity of PSE meat myofibrillar proteins with different amounts of sodium bicarbonate (SC, 0−0.6/100 g) were studied. Compared to the PSE meat myofibrillar proteins with 0/100 g SC, the texture properties and cooking yield significantly increased (p < 0.05) with increasing SC; meanwhile, adding SC caused the gel color to darken. All samples had similar curves with three phases, and the storage modulus (G') values significantly increased with the increasing SC. The thermal stability of the PSE meat myofibrillar proteins was enhanced, and the G' value at 80 °C increased with the increasing SC. Because water was bound more tightly to the protein matrix, the initial relaxation times of T21 and T22 shortened, the peak ratio of P21 significantly increased (p < 0.05), and the P22 significantly decreased (p < 0.05), which implied that the mobility of the water was reduced. Overall, SC could improve the thermal stability of the PSE meat myofibrillar proteins and increase the water-holding capacity and textural properties of the cooked PSE meat myofibrillar protein gels.

[Determination of Haloacetic Acids, Disinfection Byproducts, in Tap Water with Reversed-Phase Ultra-Performance Liquid Chromatography-High Resolution Mass Spectrometry].

Objective: To establish a method for quantitative analysis of haloacetic acids (HAAs), disinfection byproducts, in tap water with reversed-phase ultra-performance liquid chromatography-quadrupole-orbitrap high resolution mass spectrometry. Methods: Tap water samples were collected and 0.70 g/L ascorbic acid was added to eliminate residual chlorine. Then, the water samples were directly injected into the instrument for analysis after filtration. After separation on a pentafluorobenzene (PFP) column with an inner diameter of 1.0 mm at a higher linear velocity and a lower volume flow rate compared with those of a narrow-bore column, nine HAAs, namely, monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), dichloroacetic acid (DCAA), bromochloroacetic acid (BCAA), dibromoacetic acid (DBAA), trichloroacetic acid (TCAA), bromodichloroacetic acid（BDCAA), chlorodibromoacetic acid (CDBAA) and tribromoacetic acid (TBAA), were examined by negative electrospray ionization and full MS/dd-MS 2 acquisition mode. In order to adjust for the matrix effect, matrix matching calibration curves were used to quantitate the nine HAAs. Results: Good linearity was obtained for each of the nine HAAs within their respective linear ranges. The detection limits and quantification limits of the method were 0.020-1.0 µg/L and 0.060-3.0 µg/L. The recoveries were 69.8%-119%. Conclusion: The proposed method showed strengths in separation speed and qualitative accuracy. It did not require for complicated pretreatment procedures and can meet the need of tap water sample analysis.

[The Screening Approaches for 34 Common Drugs and Metabolites in Biological Samples by Liquid Chromatography Orbital Trap Mass Spectrometry].

Objective: To establish a high-performance liquid chromatography orbital trap mass spectrometry (HPLC-Obitrap MS) method for screening 34 common drugs and metabolites in biological samples. Methods: The target analytes in urine and blood samples were extracted with ethyl acetate, concentrated by nitrogen blowing and redissolved. The hair samples were washed with water and acetone, dried and cut into bits of about 1 mm, and then crushed in a freezing grinder. The analytes were extracted with methanol, and after filtration, the filtrate was used for instrumental analysis. Hypersil Gold PFP (2.1 mm×100 mm, 3 µm) column was used for chromatographic separation. Methanol and 5 mmol/L ammonium acetate solution were used as mobile phase with gradient elution at a flow rate of 400 µL/min. Mass spectrometry was done by electrospray positive and negative ion alternation mode. The data were collected using Full MS and Full MS/dd-MS2 mode. Xcalibur 4.0 software was used to control instruments and to collect data, and TraceFinder 3.3 was used for screening and identification. Results: The method's detection limits for 34 drugs and their metabolites in blood, urine and hair samples were 3.30-10700 ng/L, 4.43-5440 ng/L, 0.0350-4.21 µg/kg, respectively. The intra-day and inter-day precisions of the spiked samples at the levels of 5.0, 10, and 20 µg/L were 3.50%-6.00% and 4.18%-9.90%, respectively. A total of 1125 biological samples of urine, blood and hair were collected and screened. The results showed that 96.7% of the drug users were taking a single drug, while 3.3% were mixed drug users. The main types of drug of abuse were methamphetamine (75.8%), heroin (18.5%), ketamine (2.4%) and other drugs (3.3%), and 87.9% of the positive samples were from male users. Compared with the results of high-performance liquid chromatography triple quadrupole mass spectrometry, this method can be used to identify more types of drugs in one run and to conduct retrospective analysis. Conclusion: The method established in the study is simple and sensitive and is well suited for the screening of common drugs and metabolites in biological samples.

[Study on the Analytical Method of Solid Phase Extraction-Ultra Performance Liquid Chromatography Tandem Quadrupole Linear Ion Trap Mass Spectrometry for 12 Perfluorinated Compounds in Human Urine].

OBJECTIVE: To establish a method for simultaneous determination of 12 kinds of perfluorinated compounds (PFCs) in human urine based on ultra performance liquid chromatography tandem quadrupole linear ion trap mass spectrometry (UPLC-QTtrap-MS). METHODS: After pH adjustment with 2% formic acid, the urine samples were loaded on a WAX solid phase extraction (SPE) cartridge for extraction, purification and concentration. The eluates were collected, concentrated to dryness under nitrogen, and reconstituted with 10 mmol/L ammonium acetate aqueous solution-methanol ( V water∶ V methanol = 70∶30) before injection. UPLC was performed on a C 18 cartridge, and methanol and 10 mmol/L ammonium acetate aqueous solution was used as mobile phases with gradient elution. QTtrap-MS was operated in multiple reaction monitoring (MRM) mode, and the internal standard calibration curves were applied for quantitative analysis. RESULTS: Good linearity was obtained in the linear range, with the method detection limits and method quantification limits being 0.032 ng/L-6.5 ng/L and 0.10 ng/L-21 ng/L, respectively, for the 12 kinds of PFCs. The spiked recoveries of the 12 kinds of PFCs were 91.5%-114%, with the intra-day precision and the inter-day precision being 0.57%-16.0% and 1.88%-20.1%, respectively. The established method was applied to the determination of 12 kinds of PFCs in the urine samples of primary school students collected in one area. Nine kinds of PFCs were detected in the urine samples in this area. Among the PFCs detected, perfluorobutanesulfonic acid (PFBS) and perfluorooctanoic acid (PFOA) were the main PFCs found in the student urine samples. CONCLUSION: The method established in this study could be used to simultaneously examine 12 kinds of PFCs in urine. The method combined SPE with isotope internal standard correction and achieved good sensitivity and accuracy.

[Determination of 8-oxo-2'-deoxyguanosine and Cotinine in Urine by Hydrophilic Chromatography-tandem Mass Spectrometry with Isotope Dilution].

OBJECTIVE: To develop an assay for determination of 8-oxo-2'-deoxyguanosine and cotinine in human urine by hydrophilic chromatography tandem mass spectrometry (HILIC-MS/MS) with isotope dilution. METHODS: The urine supernatant was 1∶5 diluted with 3 mmol/L ammonium formate aqueous solution containing 15N 5-8-OHdG and D 3-cotinine as internal standard. After being filtered through a 0.22 µm water filter, the sample solution was injected into ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for analysis. Separation was performed on ACQUITY UPLC® BEH HILIC column (50 mm×3.0 mm, 1.7 µm) with isocratic elution (A∶B=10∶90) at 40 ℃. The mobile phase was composed with acetonitrile (B) and 3 mmol/L ammonium formate water soulution (A). The flow rate was 0.3 mL/min. Positive ion scan-multiple reaction monitoring (MRM) mode were used for monitoring and internal standard curves were applied for quantification. RESULTS: Good linearity was obtained under the optimal conditions. Detection limits for 8-OHdG and cotinine were 0.064 µg/L and 0.035 µg/L respectively, the quantitation limits were 0.21 µg/L and 0.12 µg/L respectively, and the recoveries of the spiked urine samples were 92.6%-102% and 102%-106% respectively. Statistical analysis of 40 urine sample determination results obtained by using the above assay showed that there were significant differences in tobacco smoke exposure and tobacco-specific nitrosamine intake between active and passive smoker ( P<0.05). The concentration of NNAL and cotinine were higher in urine samples of active smoker. Tobacco smoke exposure was positively correlated with tobacco specific nitrosamine intake in both active and passive smokers (the correlation coefficients were 0.487 and 0.786 respectively, P<0.05). CONCLUSION: We successfully established a simple and fast assay for simultaneously detecting 8-oxo-2'-deoxyguanosine and cotinine in human urine. It was sensitive and accurate for quntification via the calibration by the isotope internal standards, and can meet the needs of batch analysis.

[Determination of Aromatic Compounds Metabolites in Human Urine by Solid Phase Extraction-liquid Chromatography-Tandem Mass Spectrometry].

OBJECTIVE: To establish the method based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with solid phase extraction (SPE) for simultaneous determination of the biological metabolites of aromatic compounds, including N-acetyl-S-phenyl-L-cysteine (SPMA), N-acetyl-S-benzyl-cysteine (SBMA), p-nitrophenol (PNP), methylhippuric acids (MHA), p-Aminophenol (PAP), mandelic acid (MA), phenylglyoxylic acid (PGA) and 1-hydroxypyrene (1-OHP) in urine. METHODS: After adding 20 µL of ß-glucuronidase and 1 mL ammonium acetate buffer solution in 1 mL of urine, the sample was digested in a 37 ℃ incubator for 20 h. After digestion, the enzymatic hydrolysate was purified by PRIME HLB solid phase extraction column. The target compounds were eluted with 4 mL of acetonitrile and blown to dryness with nitrogen, reconstituted with 0.20 mL of methanol. Injected the sample solution into LC-MS/MS system for analysis after filtering with 0.22 µm filter membrane. LC separation was carried out on a reversed-phase C18 column (2.1 mm×150 mm, 3.5 µm); gradient eluting was performed at a flow rate of 0.2 mL/min. The water containing 0.1% formic acid was used as mobile phase A and methanol was used as mobile phase B. The mass spectrometry was performed with multiple reaction monitoring (MRM) mode, using alternating positive and negative ions, and internal standard curves were used for quantification. RESULTS: The eight metabolites showed good linearity within the range of 1-100 ng/mL, with a correlation coefficients greater than 0.995, and the relative precision deviation (RSDs) was 0.050%-9.95%. The method detection limits (MDLs) of the eight target metabolites were 0.041-0.12 ng/mL. The proposed method was used for urine sample analysis and the spiked recoveries were 80.1%-114.0%. CONCLUSION: The established method is quick, sensitive and accurate; it meets the requirementof the biological monitoring of aromatic compounds for the general population and occupational population.

[Detecting Nicotine and Cortinine in Hair by Hydrophilic Interaction Liquid Chromatography Tandem Mass Spectrometry].

OBJECTIVE: To develop a method for detecting nicotine and cotinine in hair by hydrophilic interaction chromatography tandem mass spectrometry. METHODS: Hair samples were hydrolyzed in sodium hydroxide solution before extraction with dichloromethane. The samples were blown to dry with nitrogen and dissolved with mobile phase. The filtrate of the samples was injected into a chromatographic-mass spectrometry system for analysis. The separation was performed by a hydrophilic column, with which methanol-0.1% ammonia was used as the mobile phase. The quantitative detection of Nicotine and Cortinine was carried out with electron spray ionization-triple quadrupole mass spectrometry. The established method was used for detecting nicotine and cotinine in 602 hair samples of pregnant women and 31 hair and urine samples of volunteers. RESULTS: A standard curve was drawn for the established method of hydrophilic liquid chromatography tandem mass spectrometry. Good linearity was obtained for detecting nicotine and cotinine in the range of 0.030-100.000 µg/L, with a detection limit (MDL) of 0.007 6 µg/g and 0.004 4 µg/g, respectively. The inter-day and intra-day precisions reached a level of less than 10%. The recoveries of the spiked samples ranged from 81.0% to 102.0%. About 0.020-0.260 µg/g nicotine and 0.004 8-0.069 0 µg/g cotinine were detected in the pregnant women without exposure to secondhand smoking (SHS), compared with 0.029-0.350 µg/g nicotine and 0.005 6-0.085 0 µg/g cotinine in those exposed to SHS. Nicotine and cotinine were also found in the hair and urine samples of volunteers, which were correlated with smoking (P < 0.05). A dose-response relationship were found between smoking and hair nicotine. CONCLUSIONS: The proposed method is accurate and sensitive for detecting nicotine and cotinine in hair samples. Hair nicotine can be a specific biomarker for assessing exposure to tobacco smoking.

[Detection of 11 Organophosphate Pesticides and Atrazine in Water by Dispersive Liquid-Liquid Microextraction Combined with Gas Chromatography Mass Spectrometry].

OBJECTIVE: To develop a method for detecting 11 organophosphate pesticides and atrazine in water samples by dispersive liquidliquid microextraction combined with gas chromatographymass spectrometry (DLLMEGC/MS) . METHODS: DLLME and GCMS parameters were optimized for efficient extraction of chemicals. The proposed method was used for detecting organophosphate pesticides in tap water and river water samples,with 200 µL of dimethylbenzene as extractant and 800 µL of methanol as dispersant. They were mixed,emulsified and dispersed into 10 mL of water samples. The extractant (1 µL) from centrifugation was injected into the GC/MS system for analyses. GC separation was performed on HP5 column (30 m×0.25 mm,0.25 µm) by temperature programming. Mass spectrometric analysis was done with EI and selected ion monitoring (SIM) mode was used for quantitative analysis. RESULTS: Good linear ranges for detecting the 11 pesticides and atrazine appeared from 2.0 ng/mL to 50 ng/mL,with a limit of 0.121.38 ng/mL. The relative standard derivations (RSDs) ranged from 5.57% to 9.85%. The average recoveries ranged from 75.5% to 107%. CONCLUSION: The method is sensitive and rapid,with simultaneous extraction and concentration procedures. The lowdensity organic solvent after extraction is easy to isolate. The method fits for analyses of organophosphate pesticides and atrazine in water samples.

[Determination of Nicotine and Cotinine in Urine by Dispersive Liquid-Liquid Microextraction Combined with Gas Chromatography-Mass Spectrometry].

OBJECTIVE: To develop a method for the determination of nicotine and cotinine in urine samples by dispersive liquid-liquid microextraction (DLLME) combined with gas chromatography-mass spectrometry (DLLME-GC/MS). METHODS: The experimental conditions for GC-MS and DLLME were investigated in detail. DLLME was performed with the following procedure: 5 mL of urine sample was adjusted to pH9. 0 with NaOH solution; NaCl was added to increase ionic strength; 100 µL chloroform (containing internal standard of quinolone) as extractant was mixed with 1 000 pL methanol as dispersant and then injected into the urine sample to make it emulsified and dispersed. The sample solution was centrifuged for 5 min at 4,000 r/min, and 1 µL of its extraction solvent was injected into the GC/MS system for analysis. GC separation was performed with DB-5 column under programmed temperature. Nicotine and cotinine were quantified using selected ion monitoring (SIM) mode of mass spectrum detection and internal standard working curve. RESULTS: Good linear relationship was obtained for detecting nicotine and cotinine ranging from 0. 2 ng/mL to 100 ng/mL, with a detection limit of 0. 010 ng/mL and 0. 022 ng/mL for nicotine and cotinine respectively. The relative standard derivation (RSD) for determination of nicotine and cotinine in urine samples were 8.2% and 9.6% respectively. The spiked recoveries ranged from 92.0% to 108.0% for nicotine, 83.0% to 110.0% for cotinine. CONCLUSION: The method is rapid, sensitive, accurate and simple, with little consumption of organic solvent. It is suitable for determination of nicotine and cotinine in urine, and can meet the requirements for evaluating human tobacco exposure.

[Detecting Thallium in Water Samples using Dispersive Liquid Phase Microextraction-Graphite Furnace Atomic Absorption Spectroscopy].

OBJECTIVE: To develope a method of solvent demulsification dispersive liquid phase microextraction (SD-DLPME) based on ion association reaction coupled with graphite furnace atomic absorption spectroscopy (GFAAS) for detecting thallium in water samples. Methods Thallium ion in water samples was oxidized to Tl(III) with bromine water, which reacted with Cl- to form TlCl4-. The ionic associated compound with trioctylamine was obtained and extracted. DLPME was completed with ethanol as dispersive solvent. The separation of aqueous and organic phase was achieved by injecting into demulsification solvent without centrifugation. The extractant was collected and injected into GFAAS for analysis. With palladium colloid as matrix modifier, a two step drying and ashing temperature programming process was applied for high precision and sensitivity. RESULTS: The linear range was 0.05-2.0 microg/L, with a detection limit of 0.011 microg/L. The relative standard derivation (RSD) for detecting Tl in spiked water sample was 9.9%. The spiked recoveries of water samples ranged from 94.0% to 103.0%. CONCLUSION: The method is simple, sensitive and suitable for batch analysis of Tl in water samples.

[Simultaneous determination of adrenaline, noradrenaline, cortisone and cortisol in plasma with HPLC/MS/MS].

OBJECTIVE: To develop a method for simultaneous determination of adrenaline, noradrenaline, cortisone and cortisol in plasma using HPLC/MS/MS. METHODS: Sample proteins were precipitated with acetonitrile and the sample solution was injected into HPLC/MS/MS after centrifugation at 15,000 r/min for 5 min. Electrospray ionization (ESI) and the positive ion detection were applied with a multiple reaction monitoring (MRM) mode for quantitative analyses. RESULTS: Under the optimal conditions, good linearity (r > 0.999) was observed in the range of 0.02-200.00 ng/mL of target compounds. The detection limit reached 4.13 pg/mL, 4.64 pg/mL, 4.29 pg/mL and 4.52 pg/mL for adrenaline, noradrenaline, cortisone and cortisol respectively. The inter-day and intra-day precisions ranged from 1.19%-5.42% and 2.16%-6.04% respectively. Satisfied results were achieved using human plasma samples, with a spiked recovery in the range of 80.0%-109.0% and a relative standard deviation of 3.93%-7.57%. CONCLUSION: The proposed method is quick, sensitive and suitable for batch analyses of plasma samples.

[Determination of organochlorine pesticides in water using solidification of floating organic drop liquid phase microextraction by gas chromatography].

OBJECTIVE: To develop a new method for simultaneous determination of eight organochlorine pesticides (OCPs) in water samples using solidification floating organic drop liquid-phase microextraction (SFO-LPME) combined with gas chromatography-electronic capture detector (GC-ECD). METHODS: The experimental conditions of SFO-LPME were determined with n-Hexadecane as extractant, water samples adjusted to pH 6.0, inonic strength increased by adding 15.0 g/100 mL NaCI. The OCPs were extracted at 55 degrees C for 10 mm and determined with GC-ECD. RESULTS: A good linearity (correlation coefficients > or = 0.996) was obtained for eight target compounds from 5 ng/I. to 100 ng/L. The method detection limits ranged from 0.24 ng/L to 0.78 ng/L. Satisfactory results were achieved with samples of river water, piped water and farmland water, with an average recovery of 76.0%-106.0% and RSD of 3.24%-11.60%. CONCLUSION: The proposed method is rapid, simple and sensitive. It is suitable for hatch analyses of eight organic chlorine pesticides in water samples.

[Determination of canthaxanthin and astaxanthin in egg yolks by reversed phase high performance liquid chromatography with diode array detection].

OBJECTIVE: A method using reversed phase high performance liquid chromatography (RP-HPLC) coupled with diode array detector (DAD) was developed for the simultaneous determination of canthaxanthin and astaxanthin in egg yolks. METHODS: Samples were extracted with acetonitrile in ultrasonic bath for 20 minutes and then purified by freezing-lipid filtration and solid phase extraction (SPE). After being vaporized to dryness by nitrogen blowing and made up to volume with methanol, the extract solution was chromatographically separated in C18 column with a unitary mobile phase consisting of acetonitrile. The proposed method was validated in terms of linearity, precision, accuracy, and limit of detection (LOD). RESULT: Regression analysis revealed a good linearity between peak area of each analyte and its concentration (r > or = 0.998). The intra- and inter-day relative standard deviations (RSDs) were less than 3.6% and 5.2%, respectively. LODs of canthaxanthin and astaxanthin were 0.035 and 0.027 microg/mL (S/N = 3). The average recoveries of canthaxanthin and astaxanthin were 91.5% and 88.7%. CONCLUSION: The proposed method is simple, fast and easy to apply.

Effect of sodium bicarbonate on techno-functional and rheological properties of pale, soft, and exudative (PSE) meat batters.

In the study, changes in salt-soluble protein (SSP) content, gel properties, rheological characteristic, and microstructure attributes of pale, soft, and exudative (PSE) pork batters with different concentrations of added sodium bicarbonate (0-0.6%) were investigated. The pH, b⁎ value, SSP content, cooking yield, texture properties, emulsion stability, and G' values at 72 °C significantly increased with the increase in sodium bicarbonate, but the texture properties and G' values of the samples with 0.4% and 0.6% did not significantly different, while the a⁎ value significantly decreased. Moreover, a greater G' value at 72 °C was in agreement with a higher hardness value of meat batter. The microstructure of cooked PSE meat batters with 0% and 0.2% sodium bicarbonate had a dense structure, and samples with 0.4% and 0.6% had some large cavities. In conclusion, the use of sodium bicarbonate can enhance the water holding capacity, texture and rheological properties of PSE meat batters by increasing their pH, SSP content, and emulsifying stability.

[Rapid determination of ethanol in blood by capillary-gas chromatography].

OBJECTIVE: To develop a method for the rapid determination of ethanol in blood with capillary-GC. METHODS: 0.50 mL of whole blood sample was taken and added with 1.00 mL of dimethyl sulfoxide (DMSO), and 2 g of anhydrous sodium sulfate. The supernatant of the sample solution was directly injected into GC for analysis. RESULTS: Ethanol was separated from other substances in the sample. The liner range of ethanol detected by the capillary-GC was 0.0-300.0 mg/100 mL, and the detection limit was 0.2 mg/100 mL. The RSD for standard solution determination was 1.36%. Satisfactory results were obtained for the determination of ethanol in whole blood samples, with recoveries ranging from 90.9% to 107.3% and a RSD of 1.98%. The combined uncertainty was 2.2%. CONCLUSION: This is a rapid, sensitive and simple method for determination of ethanol in large quantities of samples. The method has shortened the duration of analysis cycle in comparison with the traditional headspace-GC, with a reduction from 20-30 min to less than 10 min.

[Determination of adenosine in food by high performance anion exchange chromatography].

OBJECTIVE: To establish a high performance anion chromatography method for the determination of adenosine in food. METHODS: Adenosine in the food sample was extracted with Acetonitrile-water, and separated with Amino PAC PA10 Amino acid-separation column, with 0.25 mol/L NaOH as the mobile phase. A pulse ampere detector with Au as working electrode was used throughout the experiment. RESULTS: A good linear result was produced for adenosine in the range of 1.00-20.00 microg/mL. The inner-day RSD of peak area and retention time for the standard adenosine solution were 4.97% and 0.47%, respectively. The intra-day RSD of peak area and retention time for the standard adenosine solution were 6.08% and 0.52%, respectively. The proposed method was applied to food and satisfactory results were obtained, with and average recoveries of 93.3%-106.7% and 8.86% of RSD. CONCLUSION: The high performance anion exchange chromatography method is a simple, accurate, and reliable method for measuring adenosine in food, which can be completed within 10 minutes.

[Determination of monosaccharides in honey and polysaccharide hydrolyzate of functional food by high performance anion exchange chromatography].

OBJECTIVE: To develop a method for analysis of eight kinds of monosaccharides using high performance anion exchange chromatography. METHODS: Amino PAC PA-10 (2 x 250 mm) column with a pulse amperometric detector with an Au working electrode and an Ag/AgCl reference electrode was applied to determine the monosaccharides. RESULTS: The linear range was 0.1-5.0 microg/mL and the detection limits were 2-26 microg/L. The relative standard derivation for retain time and area of standard solution were 0.34%-7.42% and 0.02%-2.16% respectively. The satisfactory results were obtained for analysis of honey and polysaccharide hydrolyzate of functional food with the proposed method. The average recoveries were 81.4%-122.0%. The method was sensitive and with high precision. CONCLUSION: This method was available for determination of monosaccharides in honey and polysaccharide hydrolyzate of functional food.

Immunohistochemical distribution of NGF, BDNF, NT-3, and NT-4 in adult rhesus monkey brains.

Immunohistochemical distribution and cellular localization of neurotrophins was investigated in adult monkey brains using antisera against nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4). Western blot analysis showed that each antibody specifically recognized appropriate bands of approximately 14.7 kDa, 14.2 kDa, 13.6 kDa, and 14.5 kDa, for NGF, BDNF, NT-3, and NT-4, respectively. These positions coincided with the molecular masses of the neurotrophins studied. Furthermore, sections exposed to primary antiserum preadsorbed with full-length NGF, BDNF, NT-3, and NT-4 exhibited no detectable immunoreactivity, demonstrating specificities of the antibodies against the tissues prepared from rhesus monkeys. The study provided a systematic report on the distribution of NGF, BDNF, NT-3, and NT-4 in the monkey brain. Varying intensity of immunostaining was observed in the somata and processes of a wide variety of neurons and glial cells in the cerebrum, cerebellum, hippocampus, and other regions of the brain. Neurons in some regions such as the cerebral cortex and the hippocampus, which stained for neurotrophins, also expressed neurotrophic factor mRNA. In some other brain regions, there was discrepancy of protein distribution and mRNA expression reported previously, indicating a retrograde or anterograde action mode of neurotrophins. Results of this study provide a morphological basis for the elucidation of the roles of NGF, BDNF, NT-3, and NT-4 in adult primate brains.

[Simultaneous determination of iron, copper and cobalt in food samples by diode array detection-flow injection analysis using partial least squares calibration model].

A flow injection-CCD-diode array detection spectrophotometric method using partial least squares (PLS) algorithm for the simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction between metallic ions and 5-Br-PADAP in the presence of acetic acid-acetic sodium buffer solution (pH 5) containing 30 g x L(-1) ascorbic acid and 2% (phi) Triton X-100. The overlapped spectra of these complexes were collected by CCD diode array detector and the multi-wavelength absorbance data were processed using partial least squares algorithm. The reaction conditions and analytical parameters of FIA were investigated. The food samples can be analyzed without any separation after digestion, and the sampling rate was 45 x h(-1). The linear ranges of Fe2+, Cu+ and Co2+ were 0.2-10.0 microg x mL(-1), 0.1-5.0 microg x mL(-1), and 0.01-1.0 microg x mL(-1) and the detection limits were 0.2, 0.1 and 0.01 microg x mL(-1), respectively. The average recoveries of spiked samples were 89.4%-110.8% for the three elements. The relative standard deviation (RSD) of samples was in the range of 1.1%-12.1%. Comparing the proposed method with ICP-AES, the relative error was below 12.1%. Above all, this method is simple, quick, sensitive, selective, and easy to be apply and generalize.

[Detecting VA, VD3, VE and beta-carotene with HPLC in human serums].

OBJECTIVE: To develop a method of detecting retinol (vitamin A), vitamin D3, alpha-tocopherol (vitamin E) and beta-carotene in human serums with HPLC. METHODS: Proteins were precipitated with anhydrous ethanol. Fat-solutable vitamins in human serums were extracted with aether/petroleum ether mixture and determined with HPLC. RESULTS: The linear ranges for the retinol, VD3, alpha-tocopherol and beta-carotene were 0.012 microg/mL-500 microg/mL, 0.030 microg/mL-500 microg/mL, 0.12 microg/mL-500 microg/mL, and 0.015 microg/mL-500 microg/mL, respectively. The detection limits for the retinol, VD3, alpha-tocopherol and beta-carotene were 0.012 microg/mL, 0.030 microg/mL, 0.12 microg/mL and 0.015 microg/mL, respectively. The relative standard derivations (RSD) for the retinol, VD3, alpha-tocopherol and beta-carotene were 0.75%, 0.54%, 2.06% and 2.74%, respectively. The proposed method recovered 92%-116%, 98%-112%, 84.8%-106%, and 90%-105% retinol, VD3, alpha-tocopherol and beta-carotene in human serums respectively. CONCLUSION: The method is simple, quick and applicable to all of the four fat-solutable vitamins.