Gel Permeation Column Research Articles

Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography–tandem mass spectrometry

ABSTRACTA sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid–liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC–MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC–MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005–0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.

Extraction of cocoa proanthocyanidins and their fractionation by sequential centrifugal partition chromatography and gel permeation chromatography.

Cocoa beans contain secondary metabolites ranging from simple alkaloids to complex polyphenols with most of them believed to possess significant health benefits. The increasing interest in these health effects has prompted the need to develop techniques for their extraction, fractionation, separation, and analysis. This work provides an update on analytical procedures with a focus on establishing a gentle extraction technique. Cocoa beans were finely ground to an average particle size of <100μm, defatted at 20°C using n-hexane, and extracted three times with 50% aqueous acetone at 50°C. Determination of the total phenolic content was done using the Folin-Ciocalteu assay, the concentration of individual polyphenols was analyzed by electrospray ionization high performance liquid chromatography-mass spectrometry (ESI-HPLC/MS). Fractions of bioactive compounds were separated by combining sequential centrifugal partition chromatography (SCPC) and gel permeation column chromatography using Sephadex LH-20. For SCPC, a two-phase solvent system consisting of ethyl acetate/n-butanol/water (4:1:5, v/v/v) was successfully applied for the separation of theobromine, caffeine, and representatives of the two main phenolic compound classes flavan-3-ols and flavonols. Gel permeation chromatography on Sephadex LH-20 using a stepwise elution sequence with aqueous acetone has been shown for effectively separating individual flavan-3-ols. Separation was obtained for (-)-epicatechin, proanthocyanidin dimer B2, trimer C1, and tetramer cinnamtannin A2. The purity of alkaloids and phenolic compounds was determined by HPLC analysis and their chemical identity was confirmed by mass spectrometry.

Nazumazoles D-F, Cyclic Pentapeptides That Inhibit Chymotrypsin, from the Marine Sponge Theonella swinhoei.

Nazumazoles D-F (1-3) were isolated from the marine sponge Theonella swinhoei. The compounds gave extremely broad peaks by reversed-phase HPLC using an ODS column. HPLC using a gel permeation column was instrumental for the separation of the three compounds. Their planar structures were determined by interpretation of NMR data to be cyclic pentapeptides. Nazumazoles D-F contained one residue each of α-keto-l-norvaline (l-Knv) {or α-keto-d-leucine (l-Kle)}, l-alanyloxazole (l-Aox), d-Abu (or d-Ser), N-α-CHO-β-l-Dpr, and cis-4-methyl-l-proline. The absolute configuration of each amino acid residue was determined by Marfey's method in combination with conversion of the α-keto-β-amino acid to the α-amino acid by oxidation. Nazumazoles D-F are not cytotoxic against P388 cells at 50 μM, but inhibit chymotrypsin.

Purification, structural characterization and in vitro antioxidant activity of a novel polysaccharide from Boshuzhi

A novel polysaccharide, designated GCPB-1b, was obtained from the alkaline extract of the submerged fermentation culturing mycelium powder of Boshuzhi, Ganoderma capense. This polysaccharide was purified by ion-exchange and gel-permeation column chromatography and is a glucan (MW 2847Da). GCPB-1b has a specific optical rotation of [α]D25=+154° (c 1.0, H2O). Based on monosaccharide analysis, partial acid hydrolysis, periodic acid oxidation-Smith degradation, methylation analysis, Fourier transform-infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC–MS) and nuclear magnetic resonance (NMR) spectroscopy, the backbone of GCPB-1b was composed of (1→4)-linked-α-d-glucose residues and (1→4,6)-linked-α-d-glucose residues. Furthermore, GCPB-1b had 1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging ability (EC50 3.23μM) according to antioxidant activity tests which was greater than other antioxidants. These data suggest that GCPB-1b holds promise as an anti-aging functional food.

Analysis of lipoprotein profiles of healthy cats by gel-permeation high-performance liquid chromatography.

Density gradient ultracentrifugation (DGUC) and gel electrophoresis are conventionally used to obtain lipoprotein profiles of animals. We recently applied high-performance liquid chromatography with a gel permeation column (GP-HPLC) and an on-line dual enzymatic system to dogs for lipoprotein profile analysis. We compared the GP-HPLC with DGUC as a method to obtain a feline lipoprotein profile. The lipoprotein profiles showed large and small peaks, which corresponded to high-density lipoprotein (HDL) and low-density lipoprotein (LDL), respectively, whereas very low-density lipoprotein (VLDL) and chylomicron (CM) were only marginally detected. This profile was very similar to that of dogs reported previously. Healthy cats also had a small amount of cholesterol-rich particles distinct from the normal LDL or HDL profile. There was no difference in lipoprotein profiles between the sexes, but males had a significantly larger LDL particle size (P=0.015). This study shows the feasibility of GP-HPLC for obtaining accurate lipoprotein profiles with small sample volumes and provides valuable reference data for healthy cats that should facilitate diagnoses.

Recent Advances in Analytical Methods on Lipoprotein Subclasses: Calculation of Particle Numbers from Lipid Levels by Gel Permeation HPLC Using “Spherical Particle Model”

Recently, we developed an analytical method for determining the lipid levels and particle numbers in lipoprotein subclasses covering a wide size range from chylomicrons to small high density lipoproteins, by using gel permeation high-performance liquid chromatography (GP-HPLC). The challenges in analytical methods on lipoprotein subclasses have been addressed from 1980 by Hara and Okazaki using commercial TSK gel permeation columns. Later, the improvements in the hardware, separation and detection of lipoproteins, and the data processing software, using a Gaussian distribution approximation to calculate lipid levels of lipoprotein subclasses, have been extensively utilized in these analytical methods for over thirty years. In this review, we describe on the recent advances in analytical methods on lipoprotein subclasses based on various techniques, and the calculation of particle numbers from lipid levels by GPHPLC using the "spherical particle model". Free/ester ratio of cholesterol in particular lipoprotein subclass was accurately estimated from triglyceride, total cholesterol (free and esterified) and the size of the particle based on this model originally proposed by Shen and Kezdy.

Broadening of polymer chromatographic signals: Analysis, quantification and correction through effective diffusion coefficients

Average molecular weights and polydispersity indexes are some of the most important parameters considered in the polymer characterization. Usually, gel permeation chromatography (GPC) and multi angle light scattering (MALS) are used for this determination, but GPC values are overestimated due to the dispersion introduced by the column separation. Several procedures were proposed to correct such effect usually involving more complex calibration processes.In this work, a new method of calculation has been considered including diffusion effects. An equation for the concentration profile due to diffusion effects along the GPC column was considered to be a Fickian function and polystyrene narrow standards were used to determine effective diffusion coefficients. The molecular weight distribution function of mono and poly disperse polymers was interpreted as a sum of several Fickian functions representing a sample formed by only few kind of polymer chains with specific molecular weight and diffusion coefficient.Proposed model accurately fit the concentration profile along the whole elution time range as checked by the computed standard deviation. Molecular weights obtained by this new method are similar to those obtained by MALS or traditional GPC while polydispersity index values are intermediate between those obtained by the traditional GPC combined to Universal Calibration method and the MALS method.Values for Pearson and Lin coefficients shows improvement in the correlation of polydispersity index values determined by GPC and MALS methods when diffusion coefficients and new methods are used.

Simultaneous Determinations of Methoxylated Polybrominated Diphenyl Ethers and Polybrominated Diphenyl Ethers in Dairy Products from China by GC-MS

In this paper, the method of simultaneous determinations of methoxylated polybrominated diphenyl ethers and polybrominated diphenyl ethers in dairy products from China was investigated. PBDEs are widely used brominated flame retardant, which are increasingly reported in the environment. MeO-PBDEs are structural analogs to PBDEs, and reported as natural products and novel pollutants present in the environment. A new isotopic dilution GC-MS method was firstly developed to simultaneously determine fourteen PBDEs and eight MeO-PBDEs in dairy products (full cream milk powder, skim milk powder, pure milk and acidophilus milk) in this study. Solvent extraction, gel permeation chromatography (GPC) and silica gel column cleanup were used, some important steps and crucial parameters were modified and intensified compared with other literatures. Besides, the conditions of GC and MS were also optimized. The limits of quantitation values of 1-50, 4-20 μg kg^-1 in full cream milk powders, skim milk powders, pure milks and acidophilus milks were calculated for PBDEs and MeO-PBDEs. In addition, good repeatability and accuracy of the whole method were achieved. Moreover, Eighteen kinds of commercial full cream milk powder samples, sixteen skim milk powder samples, twenty pure milk samples and fifteen acidophilus milk samples were collected from local supermarket in Wuhan, Hubei province. These samples were analyzed to determine whether these samples were contaminated by PBDEs and MeO-PBDEs. The method was successfully applied to determine methoxylated polybrominated diphenyl ethers and polybrominated diphenyl ethers in these dairy products. Using the established methods, PBDEs and MeO-PBDEs were not detected in all samples.

Structural characterization and bioactivities of sulfated polysaccharide from Monostroma oxyspermum

Sulfated polysaccharide was isolated from Monostroma oxyspermum through hot water extraction, anion-exchange and gel permeation column chromatography. The sulfated polysaccharide contained 92% of carbohydrate, 0% of protein, 7.8% of uronic acid, 22% of ash and 33% of moisture respectively. The elemental composition was analyzed using CHNS/O analyzer. The molecular weight of sulfated polysaccharide determined through PAGE was found to be as 55kDa. Monosaccharides analysis revealed that sulfated polysaccharide was composed of rhamnose, fructose, galactose, xylose, and glucose. The structural features of sulfated polysaccharide were analyzed by NMR spectroscopy. Further the sulfated polysaccharide showed total antioxidant and DPPH free radical scavenging activity were as 66.29% at 250μg/ml and 66.83% at 160μg/ml respectively. The sulfated polysaccharide also showed ABTS scavenging ability and reducing power were as 83.88% at 125μg/ml and 15.81% at 400μg/ml respectively. The anticoagulant activity was determined for human plasma with respect to Activated Partial Thromboplastin Time (APTT) and Prothrombin Time (PT) was 20.09IU and 1.79IU at 25μg/ml respectively. These results indicated that the sulfated polysaccharide from M. oxyspermum had potent antioxidant and anticoagulant activities.

Rapid QuEChERS Approach Using Novel Solid Phase Extraction for Insecticides in Lobster and Shellfish Tissue with Gas Chromatography–Tandem Mass Spectrometry

Novel, rapid, inexpensive, and simple QuEChERS extraction followed by phospholipid solid phase extraction was successfully developed and validated for the determination of methoprene, resmethrin, bifenthrin, cyhalothrin, and permethrin in lobster and shellfish tissues by gas chromatography–tandem mass spectrometry. This method is equivalent in final sample purity to the traditional gel permeation and open column chromatography sample preparation techniques, but has clear advantages due to reductions in time, labor, solvent use, and can be performed with minimal staff training. The proposed methodology was effectively applied to the analysis of North Atlantic lobster (hepatopancreas and muscle) and shellfish tissue. The linearity of the calibration curves for all analytes were R2 > 0.9991. The surrogate recoveries were 98.2 ± 18.0%, while the target compound recoveries, for fortified samples, were in the range of 62.0%–128.8% with RSD values <17.2% for all compounds. The detection limits for the analytes ranged from 0.0056 µg/g to 0.76 µg/g with 84.4–119.5% accuracy and relative standard deviations less than 3.77%.

Selective evaluation of high density lipoprotein from mouse small intestine by an in situ perfusion technique

The small intestine (SI) is the second-greatest source of HDL in mice. However, the selective evaluation of SI-derived HDL (SI-HDL) has been difficult because even the origin of HDL obtained in vivo from the intestinal lymph duct of anesthetized rodents is doubtful. To shed light on this question, we have developed a novel in situ perfusion technique using surgically isolated mouse SI, with which the possible filtration of plasma HDL into the SI lymph duct can be prevented. With the developed method, we studied the characteristics of and mechanism for the production and regulation of SI-HDL. Nascent HDL particles were detected in SI lymph perfusates in WT mice, but not in ABCA1 KO mice. SI-HDL had a high protein content and was smaller than plasma HDL. SI-HDL was rich in TG and apo AIV compared with HDL in liver perfusates. SI-HDL was increased by high-fat diets and reduced in apo E KO mice. In conclusion, with our in situ perfusion model that enables the selective evaluation of SI-HDL, we demonstrated that ABCA1 plays an important role in intestinal HDL production, and SI-HDL is small, dense, rich in apo AIV, and regulated by nutritional and genetic factors.

Simultaneous determination of 16 synthetic colorants in hotpot condiment by high performance liquid chromatography.

A simultaneous determination method for 16 synthetic colorants in hotpot condiment was developed by high performance liquid chromatography. The samples were successively extracted with 2 mol/L carbamide solution containing 5% ammonia (dissolved in methanol) and methanol-acetone solution, and then the target analytes could be divided into two groups named as lipid-soluble and water-soluble colorants by ethyl acetate-cyclohexane with liquid-liquid extraction. The lipid-soluble and water-soluble colorants were purified by gel permeation chromatography and solid phase extraction column packed with polyamide resin, respectively. The obtained two eluates were combined, concentrated, and separated by C18 column and determined by diode array detector. Good linear relationships between peak areas and the concentrations of the synthetic colorants were obtained in the range of 0.01-50.0mg/L with correlation coefficients above 0.999 (n=10). The limits of detection and quantitation were 1-3 and 10 μg/kg for 16 synthetic colorants, respectively. The average recoveries at the spiked levels of 5, 10, 20 and 50 μg/kg were in the range of 63.2-97.1% with relative standard deviations (n=6) around 1.5-10.6%. This method is sensitive and reliable, and can be used to simultaneously determine 8 lipid-soluble and 8 water-soluble colorants in hotpot condiment.

콩 배아로 부터 Isoflavone과 Soyasaponin의 동시 분리

콩 관련 제품을 생산하는 과정에서 발생되는 부산물은 가축의 사료 및 퇴비 등에 이용되고 있으나 일부는 폐기물로 처리되어 추가 비용 및 각종 환경오염을 유발하는 등 사회적인 문제점으로 지적되고 있다. 따라서 본 연구에서는 가공 부산물로 다량 발생되는 콩 배아를 활용하여 생리활성물질인 isoflavone과 soyasaponin을 동시에 분리하는 방법을 개발하고자 실시하였다. 1. 콩 배아 methanol 추출물을 preparative <TEX>$C_{18}$</TEX> column에 주입하고, 210 nm의 파장에서 0.5% 초산 용액 30%로부터 100% acetonitrile까지 분당 15mL의 유속으로 53분간 흘려주어 isoflavone과 soyasaponin 분획을 동시에 분리하였다. 2. Preparative <TEX>$C_{18}$</TEX> column으로 분리된 isoflavone 및 soyasaponin 분획은 동결건조시켜 isoflavone 분말 ISF-1과 soyasaponin SAP-1, SAP-2, SAP-3 및 SAP-4의 분말을 얻었다. 3. Isoflavone 분획 ISF-1의 재분리는 젤투과 컬럼에서 100% acetonitrile을 분당 5 mL가 되도록 흘려주면서 254nm 파장에서 관찰하여 2종의 분획 ISF-1-1 및 ISF-1-2을 분리하였다. 4. 분리된 2종의 isoflavone 중 ISF-1-1은 그 조성이 daidzin, glycitin 및 genistin 이고, ISF-1-2는 genistin 단일물질이 주성분인 것으로 나타났다. 5. 분리된 4종의 soyasaponin 중 SP-1은 soyasaponin A계열인 Aa(MW: 1364), Ab(MW: 1436), Ac(MW: 1420), Ae(MW: 1202), Af(MW: 1274), SAP-2는 B계열인 Ba(MW: 958), Bb(MW: 942), Bc(MW: 912)와 E계열인 Bd(MW: 956), Be(MW: 940), SAP-3는 B계열인 Ba, Bb, Bc, E계열인 Bd, Be와 DDMP계열인 <TEX>${\beta}g$</TEX>(MW: 1068), SAP-4는 B계열인 Ba, Bb, Bc, E계열인 Bd, Be와 DDMP계열인 <TEX>${\beta}g$</TEX>, <TEX>${\beta}a$</TEX>(MW: 1038)가 주성분임을 알 수 있었다. The objective of present study was to simultaneously isolate of isoflavone and soyasaponin compounds from the germ of soybean seeds. Soy germ flours were defatted with hexane for 48h at room temperature, and methanolic extracts were prepared using reflux apparatus at <TEX>$90^{\circ}C$</TEX> for 6h, two times. After extraction, extracts were separated with preparative RP-<TEX>$C_{18}$</TEX> packing column (<TEX>$125{\AA}$</TEX>, <TEX>$55-105{\mu}m$</TEX>, <TEX>$40{\times}150mm$</TEX>), and collected 52 fractions were identified with TLC plate (Kieselgel 60 F-254) and HPLC, respectively. Among the identified isoflavone and soyasaponin fractions, isoflavone fractions were re-separated using a recycling HPLC with gel permeation column (Jaigel-W252, <TEX>$20{\times}500mm$</TEX>). Final fractions were air-dried, and the purified compounds of two isoflavones (ISF-1-1, ISF-1-2) and four soyasaponins (SAP-1, SAP-2, SAP-3, SAP-4) were obtained. Two isoflavone compounds (ISF-1-1, ISF-1-2) were acid-hydrolyzed for the identification of their aglycones, and confirmed by comparing with 12 types of isoflavone isomers. While the four kinds of soyasaponins were identified by using a micro Q-TOF mass spectrometer in the ESI positive mode with capillary voltage of 4.5kV, and dry temperature of <TEX>$200^{\circ}C$</TEX>. Base on the obtained results, it was conclude that ISF-1-1 is the mixture isomers of daidzin (43.4%), glycitin (47.0%), and genistin (9.6%), but ISF-1-2 is the single compound of genistin (99.8% <). On the other hand, soyasaponin SAP-1 is the mixture compounds of soyasaponin A-group (Aa, Ab, Ac, Ae, Af); SAP-2 is soyasaponin B-group (Ba, Bb, Bc) and E-group (Bd, Be); SAP-3 is soyasaponin B-group (Ba, Bb, Bc), E-group (Bd, Be), and DDMP-group (<TEX>${\beta}g$</TEX>); SAP-4 is soyasaponin B-group (Ba, Bb, Bc), E-group (Bd, Be), and DDMP-group (<TEX>${\beta}g$</TEX>, <TEX>${\beta}a$</TEX>), respectively.

Production, partial purification and characterization of protease from a phytopathogenic fungi Alternaria solani (Ell. and Mart.) Sorauer

An alkaline serine protease producing strain Alternaria solani was optimized for its enzyme production under submerged conditions. The maximum production of protease by A. solani was achieved by using sodium nitrate at the optimum concentration of 0.2% w/v. A. solani produced higher quantities (3.75 [unit/mg of protein]) of an inducible extracellular proteases on day 9 after incubation in czapek's dox broth medium amended with 1% casein as an inducer at pH 8.5, temperature 27 °C and 3% sucrose as carbon source. Extracellular proteases were precipitated by ammonium sulphate saturation (80%) method and purified on Sephadex G-100 column chromatography. The molecular mass of SDS-PAGE and Sephadex G-100 Column Gel permeation chromatography purified protease was estimated to 42 kDa. In addition, trypsin digestion of 42 kDa protein band was carried out and analyzed by MALDI-TOF for the identification of protease. The sequence IKELATNGVVTNVK (378-391) segment of the alkaline serine protease was found by using MS/MS spectrum at 1485 m/z from the purified fraction. It showed optimal activity at 50 °C and pH 9-10 and broad pH stability between pH 6-12. The protease activity was inhibited by phenyl methyl sulfonyl fluoride (PMSF), all the results indicated that the presence of a serine residue in the active site and is thus most likely a member of the serine protease family. This may function as a virulence protein during pathogenesis by A. solani. The results suggested that the presence of appreciable extracellular proteolytic activity in filamentous fungi may serve as a marker of their phytopathogenicity.

Development of an analytical approach for identification and quantification of 5-α-androst-16-en-3-one in human milk

A method was developed for the quantification of 5-α-androst-16-en-3-one in human breast milk based on application of a stable isotope dilution assay using 5α-androst-16-en-3-one-6, 6-d2. The procedure includes extraction of the human milk by hexane with subsequent clean-up of the obtained extract by gel permeation and silica gel column chromatography. The extracted samples were analyzed by gas chromatography–mass spectrometry. Using this method 5-α-androst-16-en-3-one could be identified and for the first time quantified in a concentration range of 26–155ng/kg in human milk.

New Multidetector Solution Could Lead to Safer Alternatives to Faulty Silicone Breast Implants

Abstract Researchers at the University of Akron have developed a high-resolution characterization system that incorporates six gel permeation chromatography columns, two light scattering detectors, a refractive index sensor, and a viscometer. The new system facilitates the study of separated macromolecules and is expected to play a role in the development of safer biopolymers for breast implants.

Separation, purification, and α-glucosidase inhibition of polysaccharides from Coriolus versicolor LH1 mycelia

Intracellular polysaccharides (iPs) were separated and purified from Coriolus versicolor LH1 mycelia and characterized for their α-glucosidase inhibitory properties. Three iP fractions (iPL-F5-2-1, iPL-F5-4-1, and iPL-F5-5-1) were extracted, separated, and purified from LH1 mycelia using microwave extraction technology, a DEAE-Sepharose™ CL-6B column, a Diaion® HP20 macroporous adsorption column, and a Sephadex™ G-50 gel-permeation column. The principal constituents of iPL-F5-2-1, iPL-F5-4-1, and iPL-F5-5-1 were saponins and polyphenoic compound mixtures. The enzyme inhibition activity, IC50 values, of these three fractions were 1.7, 1.8, and 0.8mg/mL, respectively. The α-glucosidase inhibitory properties were related to the presence of α-(1,4) glycosidic linkages in the polysaccharide structure and the total relative percentage of d-glucose and d-galactose in the structure of polysaccharides, other than triterpenoids.

Discovery and structural elucidation of the illegal azo dye Basic Red 46 in sumac spice

An unknown red dye was discovered in a sumac spice sample during routine analysis for Sudan dyes. LC-DAD and LC-MS/MS did not reveal the identity of the red substance. Nevertheless, using LC-high-resolution MS and isotope ratio comparisons the structure was identified as Basic Red 46. The identity of the dye was further confirmed by comparison with a commercial hair-staining product and two textile dye formulations containing Basic Red 46. Analogous to the Sudan dyes, Basic Red 46 is an azo dye. However, some of the sample clean-up methodology utilised for the analysis of Sudan dyes in food prevents its successful detection. In contrast to the Sudan dyes, Basic Red 46 is a cation. Its cationic properties make it bind strongly to gel permeation columns and silica solid-phase extraction cartridges and prevent elution with standard eluents. This is the first report of Basic Red 46 in food. The structure elucidation of this compound as well as the disadvantages of analytical methods focusing on a narrow group of targeted analytes are discussed.

Simultaneous analysis of organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) from marine samples using automated pressurized liquid extraction (PLE) and Power Prep™ clean-up

An automated pressurized liquid extraction (PLE) method followed by Power Prep™ clean-up was developed for organochlorinated pesticide (OCP) and polychlorinated biphenyl (PCB) analysis in environmental marine samples of fish, squid, bivalves, shells, octopus and shrimp. OCPs and PCBs were simultaneously determined in a single chromatographic run using gas chromatography–mass spectrometry-negative chemical ionization (GC–MS-NCI). About 5g of each biological marine sample was mixed with anhydrous sodium sulphate and placed in the extraction cell of the PLE system. PLE is controlled by means of a PC using DMS 6000 software. Purification of the extract was accomplished using automated Power Prep™ clean-up with a pre-packed disposable silica column (6g) supplied by Fluid Management Systems (FMS). All OCPs and PCBs were eluted from the silica column using two types of solvent: 80mL of hexane and a 50mL mixture of hexane and dichloromethane (1:1). A wide variety of fish and shellfish were collected from the fish market and analyzed using this method. The total PCB concentrations were 2.53, 0.25, 0.24, 0.24, 0.17 and 1.38ngg−1 (w/w) for fish, squid, bivalves, shells, octopus and shrimp, respectively, and the corresponding total OCP concentrations were 30.47, 2.86, 0.92, 10.72, 5.13 and 18.39ngg−1 (w/w). Lipids were removed using an SX-3 Bio-Beads gel permeation chromatography (GPC) column. Analytical criteria such as recovery, reproducibility and repeatability were evaluated through a range of biological matrices.

Gray matter volumetric MRI differences late-preterm and term infants

Gray matter develops rapidly during the third trimester of pregnancy, which is a critical period for lipid deposition. We measured brain volume in term and late-preterm infants to determine if it is related to disabilities in late-preterm infants. In addition, we measured serum lipid concentrations to investigate the relationship between brain volume and lipid nutrition. Magnetic resonance imaging scans were obtained in 16 late-preterm and 13 term infants. We measured cerebrum, gray matter, and white matter volumes. We performed serum cholesterol, triglyceride (TG), and lipoprotein analyses in cord blood by high-performance liquid chromatography using gel permeation columns to assess lipid nutritional levels. The gray matter volume and percent cerebrum volume of gray matter were significantly smaller in late-preterm infants (p<0.001). Head circumference and cerebrum and white matter volume did not differ between the two groups. Gray matter volume correlated positively with gestational age (r=0.647, p<0.001), head circumference (r=0.688, p<0.001), and high-density lipoprotein (HDL)-TG levels (r=0.496, p=0.006). Late-preterm infants had a normal head circumference and a lower gray matter volume than term infants. Gestational age and head circumference were significantly associated with gray matter volume. Only HDL-TG levels were significantly associated with gray matter volume. HDL-TG might contribute to the transport of fatty acids and gray matter development during the postnatal period. Thus, delayed gray matter development may partly contribute to neurodevelopmental disabilities in late-preterm infants.