Everything below concerns precision. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-06-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
Most routine HPLC testing uses reversed-phase columns, where the stationary phase is nonpolar and the mobile phase is a polar mixture such as water with an organic solvent. Analytes partition between the two phases according to polarity, size, and charge. Gradients that change solvent composition over time can separate compounds with broad retention ranges. Isocratic conditions keep solvent composition constant and suit simpler mixtures. The choice of column chemistry, pH, and temperature affects selectivity and peak shape.
Detection in HPLC testing commonly relies on ultraviolet-visible absorbance, fluorescence, refractive index, or mass spectrometry. UV detection is widely used because many organic compounds absorb light, but it requires a chromophore. Mass spectrometry provides mass-based identification and high sensitivity for trace analytes. Each detector has trade-offs in selectivity, cost, and compatibility with mobile phases. Quantification typically uses calibration curves prepared from reference standards. Results are reported as concentration, purity, or presence above a limit.
HPLC testing separates dissolved compounds by passing a liquid sample through a column packed with stationary phase. A pump delivers mobile phase at controlled flow, and the sample components interact differently with stationary and mobile phases. Compounds that spend more time in mobile phase elute earlier; those retained by stationary phase elute later. Detectors record elution as peaks, and peak area or height relates to amount. This mechanism underpins quantitative analysis of mixtures.
High-performance liquid chromatography is an analytical technique that separates components in a liquid sample by passing them through a packed column under pressure. A pump delivers a mobile phase at a controlled flow rate, and an injector introduces the sample into the stream. Differences in how analytes partition between the mobile phase and the stationary phase cause them to exit the column at different times. Detection then records a signal proportional to the amount of each separated substance. The resulting chromatogram provides retention times and peak areas for identification and quantification.
Instrumentation includes a solvent delivery system, an autosampler, a column oven, and one or more detectors. Reversed-phase columns with chemically modified silica are widely used, but normal-phase, ion-exchange, size-exclusion, and affinity modes exist for specific separations. Detectors may rely on ultraviolet absorbance, fluorescence, refractive index, or mass spectrometry. Column temperature, mobile phase composition, and flow rate are adjusted to improve resolution. System pressure is monitored because rising pressure can indicate column blockage or deteriorating packing.
| Property | Value | Notes |
|---|---|---|
| Separation mode | Reversed-phase | Nonpolar stationary phase with polar mobile phase |
| Typical column particle size | 3–5 µm | Smaller particles improve resolution but raise pressure |
| Typical flow rate | 0.5–2.0 mL/min | Depends on column dimensions and pressure limits |
| Common detection | UV-Vis absorbance | Requires analytes with chromophores |
| Typical run time | 5–30 min | Varies with method, gradient, and sample complexity |
High-performance liquid chromatography testing separates components of a liquid sample by forcing a mobile phase through a packed column. The stationary phase inside the column interacts with analytes to different degrees, so each compound exits at a characteristic retention time. A pump delivers solvent at controlled flow and pressure, while an injector introduces a precise sample volume. Detectors such as ultraviolet-visible, fluorescence, refractive index, or mass spectrometric instruments record the separated bands. The resulting chromatogram provides qualitative and quantitative information about the mixture.
Separation modes differ by the chemistry of the stationary phase and the composition of the mobile phase. Reversed-phase testing uses a nonpolar column and polar solvents, making it common for pharmaceutical, environmental, and food analytes. Normal-phase testing uses a polar column and nonpolar solvents for compounds that are poorly retained in reversed-phase systems. Ion-exchange and ion-pair methods separate charged species, while size-exclusion methods sort molecules by hydrodynamic volume. Gradient elution changes solvent strength over time to resolve complex mixtures, and isocratic elution holds solvent composition constant for simpler assays.
Key performance measures include retention time, peak area, peak height, resolution, tailing factor, and plate count. Retention time helps identify a peak under fixed conditions, but confirmation often requires a second method or detector. Peak area and height relate to concentration through calibration curves, which may be linear or nonlinear depending on the detector response. Resolution describes separation between adjacent peaks, while tailing factor and plate count describe peak shape and column efficiency. Performance checks verify these values before and during a run to confirm that the instrument is performing within limits.
System suitability testing is performed before and during analytical runs to confirm that the instrument and method are working as expected. Common checks include retention time, peak area, resolution between critical pairs, tailing factor, and theoretical plate count. Results are compared with predefined limits, and a failed check requires investigation before sample results are reported. Quality control samples at low, middle, and high concentrations are injected at intervals to monitor accuracy and precision. Blank injections detect carryover and contamination, while control charts track performance over time.
Data handling and documentation are central to HPLC quality control. Electronic systems should have audit trails that record changes to methods, sequences, and results. Integration parameters, such as peak baseline and threshold, can affect reported areas and must be defined in advance. Out-of-specification results trigger a structured investigation that may include reanalysis, instrument checks, and review of sample preparation. Regulatory inspections often examine raw data, audit trails, and training records to verify that reported results are traceable and reliable.
Routine HPLC testing depends on controlled reagents, calibrated instruments, and documented procedures. Columns degrade over time, so retention times and peak shapes are monitored for drift. Mobile phases are filtered and degassed to prevent pump damage and detector noise. Reference standards must be traceable and stored under suitable conditions. Data handling systems record injections, calculations, and audit trails. Quality control samples interspersed with unknowns help detect errors during a run.
Developing an HPLC method begins with defining the purpose, such as quantifying a main component, measuring impurities, or confirming identity. Analysts select separation mode, column, mobile phase, detection, and sample preparation based on analyte properties and matrix. Experiments vary solvent strength, pH, buffer type, and temperature to achieve resolution between critical peaks. The goal is a robust method that produces reliable results across instruments and operators. Method development often involves trial runs and statistical optimization.
Validation demonstrates that a method is suitable for its intended use. Typical performance characteristics include accuracy, precision, specificity, linearity, range, limit of detection, limit of quantitation, and robustness. Regulators and standards organizations provide frameworks, but specific requirements depend on the application and jurisdiction. System suitability tests are run before sample analysis to confirm resolution, peak symmetry, retention time repeatability, and sensitivity. A validated method is not permanently fixed; changes may require partial or full revalidation.
Quality control samples are inserted at intervals to monitor accuracy and precision throughout a batch. Blank samples detect contamination, while spiked samples assess recovery from the sample matrix. Calibration standards establish the relationship between detector response and concentration, and control samples are prepared independently from them whenever possible. Laboratories also participate in proficiency testing and maintain audit trails, instrument logs, and reagent records. Ongoing review of control charts can reveal trends before they cause out-of-specification results.
Method validation demonstrates that an HPLC procedure is suitable for its intended purpose. Common validation parameters include accuracy, precision, specificity, linearity, range, limit of detection, limit of quantification, and robustness. Accuracy reflects agreement with a reference value, while precision describes repeatability under defined conditions. Specificity shows whether the method can measure the analyte in the presence of impurities or matrix components. Validation documents are reviewed before a method is used for routine testing or regulatory submissions.
Deslorelin, sold under the brand name Suprelorin among others, is an injectable gonadotropin releasing hormone superagonist (GnRH agonist) which is used in veterinary medicine for various indications.
In October 2006, the company announced it would acquire PowerMed. On October 15, 2009, Pfizer acquired Wyeth for $68 billion in cash and stock, including the assumption of debt, making Pfizer the largest pharmaceutical company in the world. The acquisition of Wyeth provided Pfizer with a pneumococcal conjugate vaccine, trademarked Prevnar 13; this is used for the prevention of invasive pneumococcal infections. The introduction of the original, 7-valent version of the vaccine, developed by Wyeth in February 2000, led to a 75% reduction in the incidence of invasive pneumococcal infections among children under age 5 in the United States. Pfizer introduced an improved version of the vaccine in 2010, for which it was granted a patent in India in 2017. Prevnar 13 provides coverage of 13 bacterial variants, expanding beyond the original 7-valent version. By 2012, the rate of invasive infections among children under age 5 had been reduced by an additional 50%.
One Mesopotamian myth, a historiographic poem entitled "The curse of Akkad: the Ekur avenged", explains how the empire created by Sargon of Akkad fell and the city of Akkad was destroyed. The myth was written hundreds of years after Naram-Sin's life and is the poet's attempt to explain how the Gutians succeeded in conquering Sumer. After an opening passage describing the glory of Akkad before its destruction, the poem tells of how Naram-Sin angered the chief god Enlil by plundering the Ekur (Enlil's temple in Nippur.) In his rage, Enlil summoned the Gutians down from the hills east of the Tigris, bringing plague, famine and death throughout Mesopotamia. Food prices became vastly inflated, with the poem stating that 1 lamb would buy only half a sila (about 425 ml or 14.4 US fl oz) of grain, half a sila of oil, or half a mina (about 250 g or 8.8 oz) of wool. To prevent this destruction, eight of the gods (namely Inanna, Enki, Sin, Ninurta, Utu, Ishkur, Nusku, and Nidaba) decreed that the city of Akkad should be destroyed in order to spare the rest of Sumer and cursed it.
Sources: en.wikipedia.org
The "Cave of the Sixteen sword bearers" ("Höhle der Schwertträger", 十六带剑者窟) is a famous cave with a series of murals showing swordsmen wearing caftans and armed with long sword and daggers. These murals have been carbon dated to 432–538 CE. The swordsmen have also been dubbed the "Tocharian donors". The interpretations of the nationality or ethnicity of the donors have varied. Some authors claim that the donors are indeed Tocharians, an elusive people of the Tarim Basin who spoke the well-documented Tocharian language, the easternmost Indo-European language. According to this thesis, the donors in the murals are of the Indo-European type, wearing Iranian-style clothes and reddish hair. A more recent interpretation is that the sword-bearers are actually Hephthalites, who are known to have occupied the Tarim Basin from 490 to 560 CE, precisely at the time the paintings were made. Kucha was specifically part of their dominion between 502 and 556 CE. The clothing style, the iconography and the physiognomy of the donors are said to be extremely close to those depicted in the paintings of Tokharistan (Bactria), the center of Hephthalite power, at sites such as Balalyk tepe or Dilberjin Tepe. In particular, the coat with single folded lapel is considered as a result of Hephthalite influence, whereas traditional Kuchean coats had two lapels. At present, the most prevalent opinion among academics seems to be that the Hephthalites were initially of Turkic origin. Similar donors can be seen in the Kumtura Caves.
The Society recognizes achievements and promotes academic research through four annual awards. The Biemann Medal and the John B. Fenn Award for a Distinguished Contribution in Mass Spectrometry both are awarded in recognition of singular achievements or contributions in fundamental or applied mass spectrometry, with the Biemann Medal being focused on individuals who are early in their careers. The Ronald A. Hites Award is awarded for outstanding original research demonstrated in papers published in the Journal of the American Society for Mass Spectrometry. The Research Awards are given to young scientists in mass spectrometry, based on the evaluation of their proposed research. The Fellows of ASMS are awarded to individuals in recognition for their scientific contribution to mass spectrometry and for their contribution to the ASMS community. Journal of the American Society for Mass Spectrometry Measuring Mass: From Positive Rays to Proteins The past presidents of ASMS are:
In molecular biology, Enhancer of rudimentary homolog is a protein that in humans is encoded by the ERH gene. The Drosophila protein enhancer of rudimentary protein is a small protein of 104 amino acids. It has been found to be an enhancer of the rudimentary gene, involved in pyrimidine biosynthesis. From an evolutionary point of view, enhancer of rudimentary is highly conserved and has been found to exist in probably all multicellular eukaryotic organisms. It has been proposed that this protein plays a role in the cell cycle. PDBe-KB provides an overview of all the structure information available in the PDB for Human Enhancer of rudimentary homolog (ERH) PDBe-KB provides an overview of all the structure information available in the PDB for Mouse Enhancer of rudimentary homolog (ERH)
Sources: en.wikipedia.org
Promising results of therapeutic candidates are reported: phase I trialed ultrasound BBB-opening device against brain cancer (1 May), phase I trialed personalized mRNA vaccine against pancreatic cancer recurrence (10 May), a novel antibiotic (Streptothricin F) against ABR bacteria (9 May), an e-skin for prosthetic sensing (18 May), two-dose JYNNEOS vaccine against mpox appears ~86% (19 May) or ~66% (18 May) effective, and a xenografted mice-tested pan-KRAS-inhibitor against cancer (31 May).
Cloths come in various colours, sizes and designs and are worn during social and religious occasions. In a cultural context, kente is more important than just a cloth as it is a visual representation of history and also a form of written language through weaving. The term "kente" has its roots in the Akan word kɛntɛn, which means a basket, and the first kente weavers used raffia fibres to weave cloths that looked like kenten (a basket); and thus were referred to as kenten ntoma; meaning "basket cloth". Kente is also woven by the Ewe people (Ewe Kente) in the Volta Region. The main weaving centres are Agortime area and Agbozume. Agbozume has a kente market that attracts patrons from all over West Africa and the diaspora.
=== Liposomes structure === Liposomes are sphere-shaped vesicular structures self-assembled in a solvent composed of a broad type of lipids or other amphiphilic molecules. The vesicle structure of liposomes improves the effects on drug penetration through biological membranes, which enhance transdermal drug delivery.
The Freight Technology Group, responsible for identifying relevant technologies for the freight sector in the UK, has identified three key technical innovations already in use in rail freight. These include timetable advisory systems which allow drivers to track train progress against timetables via software hosted on tablets, freight collaborative decision-making systems which offer real-time information on arrivals of freight services, and mobile consisting applications which reduce the amount of information sent manually to relevant parties and authorities by collecting information and transmitting it directly. However, advancements in rail freight technology have progressed more slowly than in other sectors due to the decades-long life cycles of locomotives and railcars and the lack of power supply in freight cars. A $10 billion upgrade to the North American rail system was mandated by Congress to include automated safety overrides after a 2008 commuter train accident, laying the groundwork for autonomous rails in the United States. In 2019, mining group Rio Tinto launched the world’s first autonomous heavy-haul freight railway trains in Western Australia to deliver ore from mines to ports.
Sources: en.wikipedia.org
It separates components in a liquid sample and measures their amounts using a detector. Results can indicate concentration, purity, or identity based on retention time and detector response. The technique works for mixtures that can be dissolved and filtered.
It offers high resolution, reproducibility, and compatibility with many sample types. A single run can separate and quantify multiple analytes. It is common in pharmaceutical, food, environmental, and industrial laboratories.
Samples must be soluble in a suitable mobile phase and free of particles that can block the column. Detector response depends on analyte structure, so some compounds need derivatization or alternative detection. Complex matrices may require extensive sample preparation.
HPLC separates and detects individual compounds in a liquid sample, producing peaks at characteristic retention times. Peak area or height can be used to estimate concentration when calibrated with known standards. It does not identify unknown compounds with certainty unless additional detectors or reference materials are used.