한국 및 중국 재배종 미숙과 복분자의 엘라그산 함량의 비교

IntroductionC‐peptide is an important marker to assess residual insulin production in individuals with type 1 diabetes (T1D). The accuracy and detection limits of C‐peptide assays are important to detect C‐peptide microsecretion and to reliably observe changes over time in these people. We compared and verified two commercially available assays able to measure C‐peptide in the picomolar range.MethodsThe ultrasensitive Mercodia enzyme‐linked immunosorbent C‐peptide assay (ELISA) was compared with the Beckman immunoradiometric assay (IRMA) for C‐peptide, assessing reproducibility (coefficient of variation [CV]), limit of blank (LoB), limit of detection (LoD) and limit of quantitation (LoQ).ResultsFor both assays within‐run and between‐run variation were high at the low (around the detection limit) C‐peptide concentration range, with CVs of around 40%. LoB values for the ultrasensitive ELISA and the IRMA were 1.3 and 0.16 pmol/L respectively. LoD values were 2.4 and 0.54 pmol/L respectively. LoQ values were 9.7 and 3.8 pmol/L respectively. Only the IRMA met the specifications claimed by the manufacturer.ConclusionsThe IRMA provided the lowest threshold for quantification of serum C‐peptide. LoQ of commercially available assays should be established in‐house before applying them in research studies and clinical trials in which low C‐peptide levels have clinical or scientific relevance.

Objective: The objective of this study was to develop a new and simple reverse-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous estimation of riluzole (RZ) and levodopa (LD) in the marketed tablet dosage form. Materials and Methods: The chromatographic separation was achieved on a RP hypercil C18 column (250 × 4.6 mm i.d., 5 μm) using a mobile phase consisting of methanol and water (75:25 v/v) at a flow rate of 1.0 ml/min with the ultraviolet detection wavelength of 273 nm at ambient temperature. The developed method was validated as per the International Council on Harmonization guideline for linearity, accuracy, precision, robustness, ruggedness, limit of detection (LOD), limit of quantitation (LOQ), and specificity. Results: Results of validation studies were found satisfactory with % relative standard deviation values of <2% indicating good specificity, validity, and reliability of the method. The method showed good linearity over the concentration range of 20–80 μg/ml with correlation coefficient (r2) values of 0.990and 0.999 for RZ and LD, respectively. The mean percentage recoveries were between 99.46–99.80% and 100.15–101.24% for RZ and LD, respectively. The LOD and LOQ values were found to be 0.036and 0.012 μg/ml, and 0.110and 0.036 μg/ml for RZ and LD, respectively. The assay of RZ and LD in the marketed tablet formulation was found to be 99.67and 98.95%, respectively. Conclusion: The RP-HPLC method is reported to be simple, specific, accurate, and precise. The proposed method can be successfully applied for the routine analysis of RZ and LD in the bulk drugs as well as in combined pharmaceutical dosage forms.

Molecularly imprinted polymer cartridges coupled to liquid chromatography for simple and selective analysis of penicilloic acid and penilloic acid in milk by matrix solid-phase dispersion

Validation method on the determination of Mn in lubricating oil by direct dilution method using Atomic Absorption Spectrophotometer (AAS) in Laboratory &amp; Environment Control PT. Badak NGL Bontang has been done The validation method was done with research stages such as determination of optimum solvent, and determination of some important parameters influential for validation method such as parameter of liniearitas (r), Instrument Detection Limit (IDL), Methode Detection Limit (MDL), accuracy, precision, Limit of Detection(LOD) and Limit of Quantitation(LOQ). The result of research obtain is good, showed that the linearity value with R2 ≥ 0,997. The IDL and MDL value was 0.0021 ppm and 0.0092 ppm respectively and has been acceptability requirements of MDL. The accuracy paramater obtained recovery value with range 82.25-88.34%. The measurement of repeatability and reproducibility, the CV Horwitz value smaller than % RSD, indicating the method had a good precision. The measurement of LOD and LOQ value was 0.095 ppm 0.317 ppm respectively. Based on the result of the research determination method of Mn in lubricating oil by direct dilution method using AAS concluded valid.

Switchable-hydrophilicity solvent liquid-liquid microextraction for sample cleanup prior to dispersive magnetic solid-phase microextraction for spectrophotometric determination of quercetin in food samples

Miniaturized matrix solid-phase dispersion based on deep eutectic solvent and carbon nitride associated with high-performance liquid chromatography: A new feasibility for extraction and determination of trace nitrotoluene pollutants in soil samples

A selective, sensitive and low sample consumption GC method for determination of residual solvents in PSMA samples was developed. Selectivity with respect to solvents such as ethanol, diethyl ether, 2-propanole, acetonitrile, dichloromethane, used in manufacturing of PSMA-11, was obtained on two different GC systems and columns. In all these cases, good separation and other system suitability parameters were obtained. The values of detection limit (LOD) and limit of quantitation (LOQ) were estimated and verified experimentally for ethanol, diethyl ether, 2-propanol (IPA), acetonitrile (ACN) and dichloromethane. Full validation parameters i.e.: selectivity, limit of detection (LOD), limit of quantitation (LOQ), linearity, precision, accuracy, robustness and system suitability parameters are presented with respect to ACN and IPA. Accuracy and precision were measured on two GC systems. Statistical tests exhibit, that there are no significant differences in accuracy and precision between two GC systems

Determination of N-nitrosodimethyl amine impurity in valsartan by HPLC and LC-MS/MS methods

Comparison of amino acid derivatization reagents for LC–ESI-MS analysis. Introducing a novel phosphazene-based derivatization reagent

Ligandless reversed-phase switchable-hydrophilicity solvent liquid–liquid microextraction combined with flame-atomic absorption spectrometry for the determination of copper in oil samples

In this study, we introduce a new nondestructive measurement technique based on a thermal approach for the determination of substandard amoxicillin. The quality control of amoxicillin is critical for patient safety, and one of the essential parameters for its evaluation is the content of the active ingredient. Traditional methods for assessing amoxicillin content are defined by their time-consuming nature, reliance on skilled personnel, and frequent necessity for specific reagents. The proposed device aims to provide a rapid and low-cost alternative that can accurately measure the amoxicillin content without damaging the sample. The method validation results indicate coefficient of determination (R2) exceeding 0.99, with percent recoveries falling within the range of 98.70-103.40%. The calculated values for limit of detection and limit of quantitation were determined to be 28.11 and 85.17 mg/L, respectively. Our experiments employed amoxicillin samples with predetermined concentrations, all of which were below the standard quality. It was observed that the proposed analytical device effectively quantifies the amoxicillin content in aqueous solutions. Each measurement took no more than 10 min, underscoring the efficiency of the analysis process. The experiments were validated through independent testing at the Government Pharmaceutical Organization in Thailand and the department of engineering science in Oxford, which provides strong evidence for the effectiveness and robustness of the technique. Overall, this study demonstrates the feasibility of using a thermal approach for the nondestructive measurement of substandard amoxicillin.

In this work, we developed and validated an effective reversed-phase HPLC method with photodiode array (PDA) detection for the quantitative analysis of amphotericin B (AmB) in poly(lactide)-poly(ethylene glycol) (PLA-PEG) blend nanoparticles. Chromatographic runs were performed on a reverse phase C18 column using a mobile phase comprising a 9% acetic acid and acetonitrile mixture (40:60, v/v) under isocratic elution with a flow rate of 1 mL/min. AmB was detected at a wavelength of 408 nm. The validation process was performed considering the selectivity, linearity, precision, accuracy, robustness, limit of detection (LOD) and limit of quantitation (LOQ) of the method. A concentration range of 1-20 µg/mL was used to construct a linear calibration curve. The LOQ and LOD were 55 and 18 ng/mL, respectively. The mean recovery of AmB from the samples was 99.92% (relative standard deviation (RSD) = 0.34%, n=9), and the method was robust for changes in the flow rate of the mobile phase (maximum RSD=4.82%). The intra- and inter-assay coefficients of variation were less than 0.59%. The method was successfully used to determine the entrapment efficiency of AmB in PLA-PEG blend nanoparticles.

&lt;pre&gt;Atorvastatin is one of the first choice in the treatment of dyslipidemia associated with a decreased risk of cardiovascular disease. Drug patent expires in 2011. Currently in Indonesia circulated atorvastatin dosage tablet innovator , several trade names , and one generic. The purpose of this study was conducted to determine the quality of the preparation of atorvastatin market in Indonesia through tablet dosage uniformity test , so that the appropriate levels of drugs can provide the desired therapeutic effect.&lt;/pre&gt;&lt;pre&gt;Uniformity tablet dosage form of atorvastatin is done by measuring the uniformity of tablet weight, and content uniformity was done using ultraviolet spectrophotometry in methanol at the maximum wavelength of 246.2 nm and their validity was tested on the value of LOD (limit of detection), and LOQ (limit of quantitation). One- Way ANOVA analyzis was their also conducted. &lt;/pre&gt;The results showed that of the calculation data obtained , either in column A or column B that there is no deviation from the weight of the tablet , and based on the calculation of CV showed that all the tablets of atorvastatin in the market already qualified uniformity of weight as indicated by the value of CV &amp;lt; 5 %, and the levels atorvastatin tablet generic and tablets under the trade name meets the standard requirements of a tablet that in the range 90.0 % - 110.0 % of the amount listed on the label

Speciation analysis of mercury in sediments using vortex-assisted liquid–liquid microextraction coupled to high-performance liquid chromatography-cold vapor atomic fluorescence spectrometry

ABSTRACTFour commonly found pesticides (alachlor, atrazine, metolachlor, and simazine) in surface water were determined using dispersive pipette extraction followed by gas chromatography–mass spectrometry. The rapid mixing and equilibrium between the dispersive pipette extraction adsorbent and water sample resulted in fast and efficient extraction. Using only 5 mL of water sample, the estimated time consumption for extraction of each sample was less than 5 min. Method validation was performed to evaluate accuracy, precision, linearity, the limits of detection, and the limits of quantitation. Average recovery of above 90% was obtained with relative standard deviations below 10%, which indicated good accuracy and precision of the dispersive pipette extraction method. Coefficients of determination were all above 0.9901 and showed good linearity. For the four pesticides studied using the current method, the limits of detection ranged from 7 to 40 ng L−1, and limits of quantitation were from 20 to 130 ng L−1. Method validation results supported the application of the current method for drinking water safety monitoring per National Primary Drinking Water Regulations established by the US Environmental Protection Agency. Water samples from Lake Lanier and Stone Mountain Lake (Georgia, USS) were analyzed with this method as a preliminary work for a larger scale drinking water quality study in the future. Trace amounts of simazine and atrazine were found in lake water samples, but both were below the regulation levels of the US Environmental Protection Agency.