This is a working overview of Chromatogram, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-05-27. Anything still debated is marked as such rather than presented as settled.
HPLC testing is not a single fixed procedure; it is a family of separation modes. Reversed-phase, normal-phase, ion-exchange, size-exclusion, and affinity chromatography each suit different analyte properties. Reversed-phase methods dominate because they handle many neutral and moderately polar compounds. Detection can be optical, electrochemical, or mass spectrometric, and the detector dictates what information is available. Coupling with mass spectrometry increases selectivity and enables identification when standards are unavailable. The technique cannot separate every mixture without adjustment.
HPLC testing is an analytical technique used to separate, identify, and quantify components in a liquid sample. It relies on a pressurized mobile phase that carries the sample through a column packed with stationary phase. Different compounds travel at different rates because of interactions with the stationary and mobile phases. The resulting signal versus time is a chromatogram. Peak position indicates identity under specified conditions, while peak area or height relates to amount.
Laboratories apply HPLC testing across pharmaceutical, food, environmental, and industrial chemistry. The method can measure active ingredients, impurities, additives, preservatives, and degradation products. Sample preparation often includes dilution, filtration, and sometimes extraction or derivatization. The choice of column, mobile phase, pH, temperature, and detector depends on the analytes and matrix. Results are compared with reference standards to assign identity and concentration. Method suitability is judged by resolution, precision, and accuracy.
Routine quality control monitors retention time shifts, baseline noise, system pressure, and peak shape. Trends can reveal column aging, mobile phase preparation errors, detector drift, or sample degradation. Corrective actions may include replacing the column, preparing fresh mobile phase, or recalibrating the detector. Stability testing often uses HPLC to measure parent compound loss and degradation product formation. Open questions remain about how accelerated stability results extrapolate to long-term storage under varied conditions.
Quality control for HPLC testing combines scheduled checks, documented procedures, and review of results. Before sample analysis, system suitability testing confirms that the instrument, column, and method meet predefined criteria. Common criteria include resolution between critical peaks, retention time precision, peak tailing, and theoretical plate count. Failure triggers investigation before results are reported. Records link raw data, calculations, instrument logs, and analyst identity to each batch, supporting audits and repeat analysis.
| Property | Value | Notes |
|---|---|---|
| Abbreviation | HPLC | Also called high-performance liquid chromatography |
| Separation mechanism | Differential partitioning | Compounds distribute between mobile and stationary phases |
| Typical column chemistry | C18 (octadecylsilane) | Used in reversed-phase separations |
| Typical detector | UV-Vis or photodiode array | Mass spectrometry is common for trace and confirmatory work |
| Typical particle size | 1.8–5 µm | Smaller particles require higher pressure and can improve speed |
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.
Method validation establishes that an HPLC procedure is suitable for its intended use. Key parameters include accuracy, precision, specificity, linearity, range, limit of detection, limit of quantitation, and robustness. Accuracy measures agreement with a true or accepted value, while precision describes repeatability and intermediate precision. Specificity confirms that the method measures the analyte without interference from impurities, degradants, or excipients. Validation is documented in a protocol and report, and acceptance criteria are set before experiments begin. Regulatory guidance varies by region, but the general principles are widely harmonized.
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.
The second approach of bioprinting is autonomous self-assembly. This approach relies on the physical process of embryonic organ development as a model to replicate the tissues of interest. When cells are in their early development, they create their own extracellular matrix building block, the proper cell signaling, and independent arrangement and patterning to provide the required biological functions and micro-architecture. Autonomous self-assembly demands specific information about the developmental techniques of the tissues and organs of the embryo. There is a "scaffold-free" model that uses self-assembling spheroids that subjects to fusion and cell arrangement to resemble evolving tissues. Autonomous self-assembly depends on the cell as the fundamental driver of histogenesis, guiding the building blocks, structural and functional properties of these tissues. It demands a deeper understanding of how embryonic tissues mechanisms develop as well as the microenvironment surrounded to create the bioprinted tissues.
It is understood that rearrangement occurs between specific sites on the DNA called recombination signal sequences (RSSs). The signal sequences are composed of a conserved palindromic heptamer and a conserved AT- rich nonamer. These signal sequences are separated by non-conserved spacers of 12 or 23 base pairs called one-turn and two-turn respectively. They are within the lambda chain, k-chain and the processes of rearrangement in these regions are catalyzed by two recombination-activating genes: RAG-1 and RAG-2 and other enzymes and proteins. The segments joined due to signals generated RSSs that flank each V, D, and J segments. Only genes flank by 12 -bp that join to the genes flank by 23-bp spacer during the rearrangements and combinations to maintain VL-JL and VH-DH-JH joining.
Nandrolone to trestolone, trenbolone, norboletone, and ethylestrenol: The most commonly employed human physiological specimen for detecting AAS usage is urine, although both blood and hair have been investigated for this purpose. The AAS, whether of endogenous or exogenous origin, are subject to extensive hepatic biotransformation by a variety of enzymatic pathways. The primary urinary metabolites may be detectable for up to 30 days after the last use, depending on the specific agent, dose and route of administration. A number of the drugs have common metabolic pathways, and their excretion profiles may overlap those of the endogenous steroids, making interpretation of testing results a significant challenge to the analytical chemist. Methods for detection of the substances or their excretion products in urine specimens usually involve gas chromatography–mass spectrometry or liquid chromatography-mass spectrometry.
Participatory plant breeding (PPB) is when farmers are involved in a crop improvement programme with opportunities to make decisions and contribute to the research process at different stages. Participatory approaches to crop improvement can also be applied when plant biotechnologies are being used for crop improvement. Local agricultural systems and genetic diversity are strengthened by participatory programs, and outcomes are enhanced by farmers knowledge of the quality required and evaluation of the target environment. A 2019 review of participatory plant breeding indicated that it had not gained widespread acceptance despite its record of successfully developing varieties with improved diversity and nutritional quality, as well as greater likelihood of these improved varieties being adopted by farmers. This review also found participatory plant breeding to have a better cost/benefit ratio than non-participatory approaches, and suggested incorporating participatory plant breeding with evolutionary plant breeding.
Blood tests are also used to assess kidney function. These include tests that are intended to directly measure the function of the kidneys, as well as tests that assess the function of the kidneys by looking for evidence of problems associated with abnormal function. One of the measures of kidney function is the glomerular filtration rate (GFR). Other tests that can assess the function of the kidneys include assessment of urea and electrolyte levels such as potassium and phosphate, assessment of acid-base status by the measurement of bicarbonate levels from a vein, and assessment of the full blood count for anaemia.
Sources: en.wikipedia.org
Cardona completed his PhD at the University of Barcelona (2000–2005), where he studied developmental biology. He then undertook postdoctoral research on Drosophila neuroanatomy at UCLA (2005–2008). Between 2008 and 2011, Cardona was a Group Leader at the Institute of Neuroinformatics, jointly run by the University of Zurich and ETH Zurich. During this period, he developed computational and image-processing methods for neural circuit reconstruction and co-founded two influential open-source platforms that have become widely adopted in the neuroscience community. Cardona joined the Howard Hughes Medical Institute (HHMI) Janelia Research Campus in 2012, serving as Group Leader until 2019. In 2019, he was appointed Programme Leader at the MRC Laboratory of Molecular Biology and Professor at the University of Cambridge, where he leads research on whole-brain connectomics, circuit development, and structure–function relationships in neural systems.
The ligated mRNA-DNA-puromycin library is translated in Red Nova Lysate (Novagen) or E. coli S30 Extract System (Promega), resulting in peptides covalently linked in cis to the encoding mRNA. The in vitro translation can also be done in a PURE (protein synthesis using recombinant elements) system. PURE system is an E. coli cell-free translation system in which only essential translation components are present. Some components, such as amino acids and aminoacyl-tRNA synthases (AARSs) can be omitted from the system. Instead, chemically acylated tRNA can be added into the PURE system. It has been shown that some unnatural amino acids, such as N-methyl-amino acid accylated tRNA can be incorporated into peptides or mRNA-peptide fusions in a PURE system. After translation, the single-stranded mRNA portions of the fusions will be converted to heteroduplex of RNA/DNA by reverse transcriptase to eliminate any unwanted RNA secondary structures, and render the nucleic acid portion of the fusion more stable. This step is a standard reverse transcription reaction. For instance, it can be done by using Superscript II (GIBCO-BRL) following the manufacturer's protocol.
The National Institute for Health and Clinical Excellence (NICE), UK released updated diabetes recommendations on 30 May 2008, which recommend that self-monitoring of plasma glucose levels for people with newly diagnosed type 2 diabetes must be integrated into a structured self-management education process. The recommendations have been updated in August 2015 for children and young adults with type 1 diabetes. The American Diabetes Association (ADA), which produces guidelines for diabetes care and clinical practice recommendations, recently updated its "Standards of Medical Care" in January 2019 to acknowledge that routine self-monitoring of blood glucose in people who are not using insulin is of limited additional clinical benefit. A randomized controlled trial evaluated once-daily self-monitoring that included tailored patient messaging and did not show that this strategy led to significant changes in A1C after a year. Media related to Blood glucose monitoring at Wikimedia Commons
Activated carbon, in 50% w/w combination with celite, is used as stationary phase in low-pressure chromatographic separation of carbohydrates (mono-, di-, tri-saccharides) using ethanol solutions (5–50%) as mobile phase in analytical or preparative protocols. Activated carbon is useful for extracting the direct oral anticoagulants (DOACs) such as dabigatran, apixaban, rivaroxaban and edoxaban from blood plasma samples. For this purpose it has been made into "minitablets", each containing 5 mg activated carbon for treating 1ml samples of DOAC. Since this activated carbon has no effect on blood clotting factors, heparin or most other anticoagulants this allows a plasma sample to be analyzed for abnormalities otherwise affected by the DOACs. Carbon adsorption has numerous applications in removing pollutants from air or water streams both in the field and in industrial processes such as:
Bodybuilding supplements are dietary supplements commonly used by those involved in bodybuilding, weightlifting, mixed martial arts, and athletics for the purpose of facilitating an increase in lean body mass. Bodybuilding supplements may contain ingredients that are advertised to increase a person's muscle, body weight, athletic performance, and decrease a person's percent body fat for desired muscle definition. Among the most widely used are high protein drinks, pre-workout blends and caffeinated energy drinks, branched-chain amino acids (BCAA), glutamine, arginine, essential fatty acids, creatine, HMB, whey protein, ZMA, and weight loss products. Supplements are sold either as single ingredient preparations or in the form of "stacks" – proprietary blends of various supplements marketed as offering synergistic advantages.
Sources: en.wikipedia.org
As of 2016, challenges including optimizing sample treatment, optimizing disk surfaces, developing readers that can deploy multiple colors of light delivery and sensing for multiplexing, and for clinical use, obtaining regulatory approvals. The field is similar to lab-on-a-chip platforms. As of 2010 companies including Gyros AB, Tecan, and Burstein Technologies were working on bringing CD/DVD based immunoassays and equipment to market. Bioanalysis Microanalysis Immunoscreening List of chemical analysis methods
Boronate affinity chromatography consists of using boronic acid or boronates to elute and quantify amounts of glycoproteins. Clinical adaptations have applied this type of chromatography for use in determining long term assessment of diabetic patients through analysis of their glycated hemoglobin. Affinity purification of albumin and macroglobulin contamination is helpful in removing excess albumin and α2-macroglobulin contamination, when performing mass spectrometry. In affinity purification of serum albumin, the stationary used for collecting or attracting serum proteins can be Cibacron Blue-Sepharose. Then the serum proteins can be eluted from the adsorbent with a buffer containing thiocyanate (SCN−).
UniProt is an online repository of protein sequence and annotation data, distributed in UniProt Knowledgebase (UniProt KB), UniProt Reference Clusters (UniRef) and UniProt Archive (UniParc) databases. Originally conceived as the individual ventures of EMBL-EBI, Swiss Institute of Bioinformatics (SIB) (together maintaining Swiss-Prot and TrEMBL) and Protein Information Resource (PIR) (housing Protein Sequence Database), the increase in the global protein data generation led to their collaboration in the creation of UniProt in 2002. The protein entries stored in UniProt are cataloged by a unique UniProt identifier. The annotation data collected for the each entry are organized in logical sections (e.g. protein function, structure, expression, sequence or relevant publications), allowing a coordinated overview about the protein of interest. Links to external databases and original sources of data are also provided. In addition to standard search by the protein name/identifier, UniProt webpage houses tools for BLAST searching, sequence alignment or searching for proteins containing specific peptides.
Amylin, or islet amyloid polypeptide (IAPP), is a 37-residue peptide hormone. It is co-secreted with insulin from the pancreatic β-cells in the ratio of approximately 100:1 (insulin:amylin). Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing spikes in blood glucose levels after a meal. IAPP is processed from an 89-residue coding sequence. Proislet amyloid polypeptide (proIAPP, proamylin, proislet protein) is produced in the pancreatic beta cells (β-cells) as a 67 amino acid, 7404 Dalton pro-peptide and undergoes post-translational modifications including protease cleavage to produce amylin.
Sources: en.wikipedia.org
It measures the presence and amount of one or more compounds in a liquid sample. Separation occurs in a column, and detection produces a signal proportional to concentration. Identification usually requires comparison with a known reference standard under the same conditions.
In most cases the sample is consumed or altered during analysis, though some detectors are non-destructive. Fractions can be collected after separation for further study. Repeated testing therefore requires additional sample.
Run times range from under a minute for fast methods to over an hour for complex separations. Sample preparation, equilibration, and data review add time. Throughput depends on instrument configuration and method requirements.
System suitability is typically performed before each batch or according to the validated method and laboratory procedure. Some long runs include periodic checks during analysis. The required frequency depends on regulatory expectations and method performance.