Quality consistency evaluation of commercial transfer factor injections by chromatographic fingerprint combined with multivariate statistical analysis

The current quality control methods relying mainly on chromogenic reaction can hardly ensure the quality and safety of the biochemical drug with complex chemical composition. Therefore, a chromatographic fingerprint method was developed for the quality evaluation of a multicomponent biochemical drug, transfer factor injection. High‐performance liquid chromatography fingerprint was measured by using a C₁₈ column (250 × 4.6 mm, 5 µm) with a mobile phase composed of 0.1% trifluoroacetic acid–water and 0.085% trifluoroacetic acid–acetonitrile under gradient elution. The developed method was validated and was subsequently applied to 57 batches of commercial products which were sampled by National Drug Assessment Program. High‐resolution mass spectrometry analysis was performed on characteristic peaks of fingerprints, and a series of amino acids, nucleosides, and deoxynucleosides were identified. In the fingerprint assessments, principal component analysis and Hotelling T² analysis yielded the best results. The results generally indicated that there was a significant difference among products of batch‐to‐batch or from different manufacturers. Abnormal samples and its discriminatory components were also explored. In summary, the established fingerprinting method with multivariate statistical analysis could offer an efficient, reliable, and practical approach for quality consistency evaluation of transfer factor injection, providing a reference for the quality control of other multicomponent biochemical drugs.     

Determination of phosphate compounds in meat products by 31-Phosphorus Nuclear Magnetic Resonance spectroscopy with methylenediphosphonic acid after alkaline extraction

Modification of the extraction procedure and application of the ³¹P NMR method for the determination of polyphosphates in meat products were studied. In the elaborated procedure threefold water extraction at alkaline pH (borate buffer and 0.1 M EDTA) was applied. Furthermore, the new external standard for ³¹P NMR determination of phosphates was proposed. Obtained recoveries were between 95 and 99% and variation coefficients (CV) was ≤5%, indicating an increase in accuracy and the precision of the proposed procedure in relation to the spectrophotometric method. The described procedure of sample preparation with ³¹P NMR method was applied for the determination of polyphosphate additives in meat products. The satisfactory precision (CV = 0.39-3.40%) shows the benefit of the NMR method in the routine analysis of the phosphate ions in meat products.     

Determination of 14 heterocyclic aromatic amines in meat products using solid‐phase extraction and supercritical fluid chromatography coupled to triple quadrupole mass spectrometry

A novel, simple, and sensitive method has been developed for simultaneous determination of 14 heterocyclic aromatic amines in meat product using solid‐phase extraction combined with ultrahigh‐performance supercritical fluid chromatography coupled to tandem quadrupole mass spectrometry. The analytes could be separated within 7 min and identified using their retention times and mass. The developed method was validated based on the linearity, limits of quantification, precision, and accuracy. The recovery ranged from 52.3 to 97.5% with an acceptable standard deviation, which is not higher than 6%. The limits of quantitation ranged from 0.03 to 0.17 µg/kg. The selectivity and sensitivity were satisfactory in multiple reaction monitoring mode. The method was applied to commercial meat products, and the results demonstrated that the novel method has potential for the analysis of the targets in food matrices. This is the first work reporting the simultaneous quantification of 14 heterocyclic aromatic amines by means of ultrahigh‐performance supercritical fluid chromatography coupled to tandem quadrupole mass spectrometry.     

Mechanistic aspects of electrochemical hydride generation for cadmium

A reversed-phase chromatographic method has been developed and optimised in order to detect and quantitate soybean proteins in commercial heat-processed meat products. The optimised conditions consisted of a linear binary gradient tetrahydrofurane-water-0.05% trifluoroacetic acid at a flow rate of 1 mL/min. Meat products were defatted with acetone and soybean proteins were extracted with a buffered solution at pH 9.60. The injection of this extract into the chromatographic system enabled the detection of soybean proteins in heat-processed meat products in about 12 min. The method enabled the detection and quantitation of additions of 0.38% (w/w) and 0.63% (w/w), respectively, of soybean proteins (related to 10 g of initial product). The method has been proven to be precise with relative standard deviations (R.S.D.) for repeatability, intermediate precision, and internal reproducibility lower to 7.0%. Recoveries obtained for spiked meat products were close to 100% and no matrix interferences were observed. The application of the method to commercial heat-processed meat products in whose formulation soybean proteins were present yielded soybean protein contents ranging from 0.90% to 1.54%, below the maximum levels established by regulations.     

Phosphate additives determination in meat products by 31-phosphorus nuclear magnetic resonance using new internal reference standard: hexamethylphosphoroamide

New ³¹P NMR internal reference standard - hexamethylphosphoroamide (HMPA) was applied for determination of added polyphosphates and their ionic forms in raw pork meat and meat products. Phosphate species were determined after extraction with a boric acid buffer (pH = 9) and EDTA solution, using internal standard (HMPA) procedure. Hexamethylphosophoroamide was also used as the NMR reference standard. Linear correlations between phosphates and polyphosphate concentrations and ³¹P NMR signal areas were found in the range 81-5236 mg P/dm³, presenting 95-99% recovery and variation coefficient (CV) ≤ 5%. Studied HMPA procedure revealed shorter analysis time and the same recovery (>95%) and precision (CV = 1.3-2.7%) in comparison to MDPA method. Results of phosphate determination by both ³¹P NMR methods were tested against the molybdenumvanadate yellow spectrophotometric method (standard PN-ISO 13730, 1999) using standard reference material (certified phosphate solution).     

湿法消解-原子荧光光谱法测定农产品中的硒

硒是典型的双功能元素,其在人体内的安全范围较窄,适量的硒摄入有利于健康,摄入过量则会导致硒中毒.采用湿法消解样品,对样品前处理、仪器条件、还原剂硼氢化钾浓度、预还原时间等条件进行优化,通过对方法的检出限、准确度和精密度进行研究,建立了湿法消解-原子荧光光谱法测定农产品中硒的方法.结果显示,针对不同浓度范围的标准物质测定...     

Crude fat, hexanes extraction, in feed, cereal grain, and forage (Randall/Soxtec/submersion method): collaborative study

A method for determining crude fat in animal feed, cereal grain, and forage (plant tissue) was collaboratively studied. Crude fat was extracted from the animal feed, cereal grain, or forage material with hexanes by the Randall method, also called the Soxtec method or the submersion method. The use of hexanes provides for an alternative to diethyl ether for fat extractions. The proposed submersion method considerably decreases the extraction time required to complete a batch of samples compared to Soxhlet. The increase in throughput is very desirable in the quest for faster turnaround times and the greater efficiency in the use of labor. In addition, this method provides for reclamation of the solvent as a step of the method. The submersion method for fat extraction was previously studied for meat and meat products and was accepted as AOAC Official Method 991.36. Fourteen blind samples were sent to 14 collaborators in the United States, Sweden, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.23 to 5.80% for crude fat. Among-laboratory (including within) relative standard deviation (reproducibility) ranged from 1.88 to 14.1%. The method is recommended for Official First Action.     

湿法消解-原子荧光光谱法测定农产品中的硒

硒是典型的双功能元素,其在人体内的安全范围较窄,适量的硒摄入有利于健康,摄入过量则会导致硒中毒。采用湿法消解样品,对样品前处理、仪器条件、还原剂硼氢化钾浓度、预还原时间等条件进行优化,通过对方法的检出限、准确度和精密度进行研究,建立了湿法消解-原子荧光光谱法测定农产品中硒的方法。结果显示,针对不同浓度范围的标准物质测定值均在参考值范围内。方法检出限为0.057μg/L,相对标准偏差(RSD)为0.89%～2.7%,加标回收率为93.7%～101%,方法准确、高效、可操作性强,适用于批量农产品中硒的准确检测。     

Dual‐layer column filtration cleanup and gas chromatography‐tandem mass spectrometry detection for the analysis of 39 pesticide residues in porcine meat

A rapid and effective method was developed for the analysis of 39 pesticide residues in porcine meat with dual‐layer multiplug filtration cleanup and gas chromatography‐tandem mass spectrometry detection. The cleanup process was performed with columns packed with two layers, namely multiwalled carbon nanotubes, C18 and anhydrous magnesium sulfate (MgSO₄) as top layer, while mixture of florisil and MgSO₄ as bottom layer. A single‐layer method was tested in parallel, with columns packed with the same amount of absorbents. Extraction conditions and filtration cleanup process were optimized to obtain satisfied method performance. Method linearity was calculated with coefficients of determination more than 0.995. The limits of quantitation were verified with acceptable accuracy at the lowest spiked concentration of 0.01 mg/kg (except pyrimethanil). The recoveries at three fortified levels (0.01, 0.05, and 0.1 mg/kg) in five replicates were between 74 and 118% (except pyrimethanil) with relative standard deviations range from 1 to 16%. The matrix effects were in the range of 1.01 to 2.84. This new method was applied for the analysis of multipesticide residues in market samples of porcine meat. This study showed the dual‐layer multiplug filtration cleanup demonstrated better performance than that with the single‐layer columns in cleanup of porcine meat.     

Crude fat, diethyl ether extraction, in feed, cereal grain, and forage (Randall/Soxtec/submersion method): collaborative study

A method for determining crude fat in animal feed, cereal grain, and forage (plant tissue) was collaboratively studied. Crude fat was extracted from the animal feed, cereal grain, or forage material with diethyl ether by the Randall method, also called the Soxtec method or the submersion method. The proposed submersion method considerably decreases the extraction time required to complete a batch of samples. The increase in throughput is very desirable in the quest for faster turnaround times and the greater efficiency in the use of labor. In addition, this method provides for reclamation of the solvent as a step of the method. The submersion method for fat extraction was previously studied for meat and meat products and was accepted as AOAC Official Method 991.36. Fourteen blind samples were sent to 12 collaborators in the United States, Sweden, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.09 to 9.26% for crude fat. Among-laboratory (including within) relative standard deviation (reproducibility) ranged from 1.0 to 21.0%. The method is recommended for Official First Action.     

Quantification of meat proportions by measuring DNA contents in raw and boiled sausages using matrix-adapted calibrators and multiplex real-time PCR

The quantification of meat proportions in raw and boiled sausage according to the recipe was evaluated using three different calibrators. To measure the DNA contents from beef, pork, sheep (mutton), and horse, a tetraplex real-time PCR method was applied. Nineteen laboratories analyzed four meat products each made of different proportions of beef, pork, sheep, and horse meat. Three kinds of calibrators were used: raw and boiled sausages of known proportions ranging from 1 to 55% of meat, and a dilution series of DNA from muscle tissue. In general, results generated using calibration sausages were more accurate than those resulting from the use of DNA from muscle tissue, and exhibited smaller measurement uncertainties. Although differences between uses of raw and boiled calibration sausages were small, the most precise and accurate results were obtained by calibration with fine-textured boiled reference sausages.     

Preconcentration and analysis of Rhodamine B in water and red wine samples by using magnesium hydroxide/carbon nanotube composites as a solid‐phase extractant

A convenient and accurate analysis approach that combined solid‐phase extraction and high‐performance liquid chromatography was developed to determine the amount of Rhodamine B in red wine and Xiang‐jiang river water samples. A novel composite, magnesium hydroxide/carbon nanotube composites, was synthesized and used as the solid‐phase extractant for the preconcentration/analysis of Rhodamine B. Magnesium hydroxide/carbon nanotube composites, which combined the merits of carbon nanotubes and magnesium hydroxide, exhibited acceptable adsorption and desorption efficiencies for Rhodamine B. The linear range of the proposed solid‐phase extraction with high‐performance liquid chromatography method for Rhodamine B was 0.05–20.0 mg/L, with a limit of detection of 3.6 μg/L. The precision and reproducibility of the developed solid‐phase extraction with high‐performance liquid chromatography method and the batch‐to‐batch reproducibility of the solid‐phase extractant were also validated at spiking levels of 0.5 and 2.0 mg/L. The recovery of Rhodamine B was 94.33–106.7%, and the recovery relative standard deviations of the intra‐ and interday precisions were ≤ 3.83 and ≤ 6.01%, respectively. The relative standard deviation of the batch‐to‐batch reproducibility was ≤ 7.98%.     

Batch Injection Analysis with Amperometric Detection for DNA Biosensing Applications

In this work, batch injection analysis with the amperometric detection (BIA‐AD), employing a detection cell designed to adapt a screen‐printed carbon electrode (SPCE) was used for the first time as a robust electroanalytical system for DNA biosensing applications. The sensitive amperometric detection was used to evaluate the structural changes in double‐stranded DNA (dsDNA) after UV‐C irradiation of its solution for a given time. Batching of DNA samples was performed by precise electronic pipette microinjection of an irradiated sample aliquot onto the unmodified activated SPCE surface incorporated in the BIA‐AD system. Using the optimized experimental conditions (40 μL of 1 mg mL^?1 dsDNA in a 0.1 M phosphate buffer of pH 7.4 sampled at the injection speed degree of 6 and detected at the potential of +1.5 V vs silver pseudo‐reference electrode), a time‐dependent response (gradual decrease of amperometric signal up to 58 % after 10 min of the irradiation) was found for the detection of damage to low molecular weight salmon sperm dsDNA. The advantages of this low‐dimensional and cost‐effective measuring system can be utilized not only for the quantification of DNA damage/degradation by UV irradiation, but they are also promising for studying other types of DNA interactions.     

Preparation of eicosapentaenoic acid ethyl ester from fish oil ethyl esters by continuous batch chromatography

Fish oils are rich in eicosapentaenoic acid, which has the wide‐ranging biological activities. The rapid and efficient separation of eicosapentaenoic acid ethyl ester from fish oils ethyl ester is still regarded as a challenge. In this study, we described an effective and flexible chromatography for eicosapentaenoic acid ethyl ester preparation, named continuous batch chromatography, which combined the batch chromatography with the continuous chromatographic operation mode. After continuous batch chromatography experiment, the recovery of eicosapentaenoic acid ethyl ester was 82.01%, the average relative purity and the relative highest purity of eicosapentaenoic acid ethyl ester were 97.82 and 98.98%. The productivity of continuous batch chromatography was 5.48 times higher than that of batch chromatography, while the solvent consumption of eicosapentaenoic acid ethyl ester was 78% of the batch chromatography. This study provided a reference for the separation of the targeted chemical component from multi‐component mixtures.     

Liquid‐liquid Extraction Coupled to Batch Injection Analysis for Electroanalysis of Levofloxacin at Low Concentration Level

This work presents the integration between phase‐separation by magnetic‐stirring salt‐induced high‐temperature liquid‐liquid extraction (PS‐MSSI‐HT‐LLE) and batch injection analysis with amperometric detection (BIA‐AD) as an alternative strategy for pre‐concentration of analytes before hydrodynamic electroanalysis. To demonstrate the performance of this analytical system, the emerging contaminant levofloxacin was quantified in tap, aquarium and lake water at low concentration level. In the optimized conditions, BIA‐AD enabled fast (160 h⁻¹) and reproducible results (RSD<2 %) and the PS‐MSSI‐HT‐LLE allowed the detection of levofloxacin concentration levels not detected by direct electroanalysis (70 and 80 nmol L⁻¹) corresponding to 100‐folds enrichment factors. The performance of proposed method was evaluated by addition‐recovery test and was obtained satisfactory recovery values (between 70 and 96 %). Moreover, PS‐MSSI‐HT‐LLE allows the pre‐concentration of many samples simultaneously, which is advantageous over pre‐concentration on working electrode surface (stripping methods).     

Determination of selenium in meat products by hydride generation atomic absorption spectrophotometry

Wet digestion using a mixture of nitric, sulfuric, and perchloric acids and an aluminum block digester effectively and rapidly decomposed meat samples for selenium determination by hydride generation atomic absorption spectrophotometry. Digestion did not require constant attention by an operator. Selenium recoveries (range, 94-105%) from National Institute of Standards and Technology standard reference materials and spiked samples were used to validate method accuracy. Coefficients of variation (CVs) of repeatability of in-house reference materials used for precision study were 6.4 and 5.6%, respectively, for seafood mix and mutton liver. Selenium levels in meat products from Brisbane markets varied widely: 0.042-0.142, 0.081-0.42, and 0.050-0.198 microgram/g (wet weight) respectively, for beef, chicken, and pork. Overall, selenium levels in manufactured meat ranged from 0.041 to 0.189 microgram/g. The levels of selenium found in this study were generally lower than those reported in Finland but comparable with those reported in some parts of the United States.     

Determination of synthetic dyes in bean and meat products by liquid chromatography with tandem mass spectrometry

A sensitive and efficient method was developed for the simultaneous determination of eight synthetic dyes (Chrysoidin, Auramine O, Sudan(I–IV), Para Red, and Rhodamine B) in bean and meat products using high‐performance liquid chromatography with tandem mass spectrometry. A simple extraction procedure using acetonitrile has been applied for the extraction of these dyes from spiked bean and meat samples. Chromatographic separation was achieved on a Waters XTerra C₁₈ column (2.1 × 150 mm, 5 μm) with a multistep gradient elution. Detection and quantification were performed using mass spectrometry in multiple reaction monitoring mode. Linear calibrations were obtained with correlation coefficients R² > 0.99. The limits of detection and quantification for the eight dyes were in the ranges of 0.03–0.75 and 0.1–2.0 μg/kg depending on matrices, respectively. The recoveries of these dyes in different food matrices were between 71.2 and 116.9% with relative standard deviations <15.2%, suggesting that the developed method is promising for the accurate quantification of the eight dyes at trace levels in bean and meat products.     

Development of a polymerase chain reaction and capillary gel electrophoresis method for the detection of chicken or turkey meat in heat-treated pork meat mixtures

A polymerase chain reaction and capillary gel electrophoresis (PCR-CGE) method with ultraviolet (UV) or laser induced fluorescence detection (LIF) was established for the detection of chicken or turkey in heat-treated pork meat mixtures. Mitochondrial DNA samples extracted from heat treated meat were amplified with their corresponding specific primers yielding PCR products between 200 and 300 bp. LIF detection was superior than UV detection in terms of precision and sensitivity for the study of DNA fragments. The CGE-LIF method was highly reproducible and accurate for determining DNA fragment size. The PCR-CGE-LIF was sensitive since a significant fluorescent signal was obtained at the minimum admixture level employed of 1% in meat mixtures. Thus, the PCR-CGE-LIF method established was useful for the detection of chicken or turkey in heat treated meat mixtures and may prove to be useful for the detection of poultry meat in pork processed products.     

基于多肽标记物分析的肉制品掺伪定量检测技术

该文开发了一种基于多肽标记物分析的肉制品掺伪检测技术,可同时进行定性和定量分析。样品经蛋白质提取和胰蛋白酶消化后,采用高分辨质谱(HRMS)和生物信息学工具,寻找牛、鸡、鸭、猪和羊5种肉类的特异性热稳定多肽标记物。在多反应监测(MRM)模式下,通过高效液相色谱-串联四极杆质谱(HPLC-QQQ-MS)对这些标记物进一步验证。使用由两种不同质量分数的肉类混合物(0%~100%)建立定量校准曲线,测定低限可达1%。采用该方法对市售的实际样品进行测试,验证结果表明该方法是一种可靠、有效的肉制品鉴定手段,可同时用于生肉和熟肉掺伪的定量检测。     

Voltammetric Determination of Pb,Cu and Hg in Biodiesel Using Gold Screen‐printed Electrode: Comparison of Batch‐injection Analysis with Conventional Electrochemical Systems

This article compares the use of batch‐injection analysis (BIA) with a conventional batch system for the anodic stripping voltammetric (ASV) determination of Pb, Cu and Hg in biodiesel using screen‐printed gold electrode (SPGE). The optimized BIA conditions were 200 µL of injection volume of the digested samples at 5 µL s^?1 directly on the working electrode of the SPGE immersed in 0.1 mol L^?1 HCl solution. Therefore, BIA‐ASV presented the advantages of low sample consumption, which extended the SPGE lifetime to a whole working day of analyses, and potential for on‐site analysis using battery‐powered micropipettes and potentiostats. Although presenting lower sensitivity than conventional systems, the BIA‐ASV presented detection limit values of 1.0, 0.5 and 0.7 µg L^?1, respectively for Pb, Cu and Hg, a linear range between 20 and 280 µg L^?1, and adequate recovery values (90–110 %) for spiked biodiesel samples.