method validation raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Routine HPLC testing compares a sample result with a calibration curve prepared from known reference standards. Peak area or peak height is plotted against concentration, and the curve is used to estimate unknown amounts. Retention time supports tentative identification when compared with a standard, though mass spectrometry or another confirmatory method may be needed for definitive identification. Pre-run checks verify repeatability, resolution, and peak symmetry before sample analysis. Limits of detection and quantification describe the smallest amounts that can be reliably observed or measured. Sample preparation, filtration, and degassing help prevent column damage and inconsistent results.
High-performance liquid chromatography is an analytical technique that separates components in a liquid sample. A pump moves a liquid mobile phase through a column packed with a solid stationary phase. Compounds interact differently with both phases and travel at different rates, leaving the column at distinct retention times. A detector records these arrivals as peaks on a chromatogram. The resulting pattern supports identification and quantification of substances in mixtures. Modern instruments use high pressure to force solvent through small particles, which improves speed and resolution compared with older low-pressure liquid chromatography methods.
Separation in HPLC depends on the chemistry of the stationary phase, the composition of the mobile phase, and the physical properties of the column. Reverse-phase separations use a nonpolar stationary phase and a polar mobile phase, and they are common for many organic compounds. Ion-exchange, size-exclusion, and normal-phase modes serve other classes of analytes. Gradient elution changes solvent strength over time, while isocratic elution holds it constant. Flow rate, temperature, particle size, and column length all influence peak shape and resolution. Detection may use ultraviolet absorbance, fluorescence, refractive index, or mass spectrometry, depending on the analyte and the required sensitivity.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common abbreviation | HPLC | High-performance liquid chromatography |
| Separation basis | Differential partitioning | Between liquid mobile phase and solid stationary phase |
| Common mode | Reverse phase | Nonpolar column, polar mobile phase |
| Typical detector | UV-Vis absorbance | Widely used for compounds with chromophores |
| Typical column particle size | 2–5 µm | Smaller particles can improve resolution |
High-performance liquid chromatography is an analytical technique that separates components of a liquid sample by passing it 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 interaction with the stationary phase cause analytes to migrate at different rates. Detectors record elution as peaks, and a data system converts signals into a chromatogram. The method is suited to compounds that dissolve in a liquid and are not volatile enough for gas chromatography.
Reversed-phase chromatography dominates modern HPLC testing, using a nonpolar stationary phase such as chemically bonded octadecyl groups and a polar mobile phase of water mixed with organic solvent. Analytes partition between the mobile and stationary phases according to hydrophobicity. Gradient elution changes the mobile phase composition over time to separate compounds with a wide range of retention. Isocratic elution keeps the composition constant and is simpler for routine assays. Column temperature, pH, and flow rate influence selectivity, peak shape, and retention time, so these parameters are controlled during a validated method.
Quality control laboratories use HPLC to check identity, purity, concentration, and stability of raw materials and finished products. A validated method specifies the column, mobile phase, flow rate, detection wavelength, injection volume, and run time. Samples are prepared and compared against reference standards of known concentration. The resulting chromatogram provides quantitative data, such as assay values and impurity levels. This approach is common in pharmaceutical, food, environmental, and industrial testing where consistent measurements are required.
Method validation demonstrates that an analytical procedure is suitable for its intended purpose. Typical validation characteristics include accuracy, precision, specificity, linearity, range, limit of detection, limit of quantitation, and robustness. Regulatory guidance from bodies such as the International Council for Harmonisation and the United States Pharmacopeia outlines expectations, though specific criteria depend on the product and method. System suitability tests are run before sample analysis to confirm resolution, peak symmetry, column efficiency, and injection repeatability. Failure of these checks can invalidate a batch of measurements.
Practical HPLC testing depends on careful sample preparation and instrument maintenance. Samples may require filtration, dilution, pH adjustment, or extraction to avoid column damage and matrix interference. Mobile phases are degassed and filtered, and columns are equilibrated before injection. Common problems include peak tailing, baseline drift, ghost peaks, carryover, and co-elution of analytes. Documentation of instrument logs, calibration records, and electronic audit trails supports data integrity and traceability. Ongoing training and routine maintenance help reduce variability between analysts and laboratories.
Method validation establishes that an HPLC procedure is suitable for its intended purpose. Typical parameters include accuracy, precision, specificity, linearity, range, limit of detection, limit of quantitation, robustness, and solution stability. Accuracy reflects closeness to a reference value, while precision reflects agreement among repeated measurements. Specificity shows whether the method can measure the analyte without interference from matrix components. Validation is documented through protocols and reports, and the required extent depends on the method's use and regulatory context.
Routine quality control uses system suitability, blank injections, check standards, and control samples to detect drift or contamination. System suitability criteria may specify minimum resolution, maximum tailing factor, and a permitted range for repeated injections. Blank injections reveal carryover or solvent contamination, while check standards confirm calibration accuracy over a batch. Control samples with known analyte levels can show whether results remain within statistical limits. When a control result falls outside limits, the analyst investigates the cause and may invalidate affected results before repeating the batch.
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.
==== Antioxidant activity ==== Honokiol has also been proposed as an antioxidant. The compound protects against lipid peroxidation by interfering with ROS production and migration. Accumulation of ROS extracellularly causes macromolecular damage while intracellular accumulation may induce cytokine activation.
Background retinopathy Also known as non-proliferative retinopathy Basal rate A continuous supply of something. In the case of diabetes, the low levels of insulin usually maintained in the absence of perturbing events (e.g., food, infection, stress, ...). Beta cell One of the cell types found in the Islets of Langerhans in the pancreas. They are the source of insulin, and contain mechanisms which watch blood glucose levels and which secrete (or not) insulin in response. Beta cell transplantation See: Islet cell transplantation. Biosynthetic human insulin A man-made insulin that is chemically identical to like human insulin. See also: Human insulin. Biphasic insulin A type of pharmaceutical insulin that is a mixture of intermediate- and fast-acting insulin. Blood glucose Glucose is a simple sugar and the primary fuel for body cells. It is absorbed from some foods (or produced from starchy ones), absorbed into the cells (for about 2/3 of cells, this is under control of insulin), stored temporarily in the liver as glycogen, made in starvation from the glycerin backbone of triglycerides, and from a few amino acids. Glucose metabolism anomalies are the cause of diabetes mellitus. Blood glucose meter A machine which electrochemically or coloristically, determines the current level of glucose in a blood sample. They have been getting progressively smaller and less expensive since they were first introduced. The expense of testing is primarily in the one time use strips used which are unique to each testing machine.
=== Gold === Chrysopoeia, the artificial production of gold, is the traditional goal of alchemy. Such transmutation is possible in particle accelerators or nuclear reactors, although the production cost is estimated to be a trillion times the market price of gold. Since there is only one stable gold isotope, 197Au, nuclear reactions must create this isotope in order to produce usable gold. In 1941, Rubby Sherr, Kenneth Bainbridge and Herbert H. Anderson synthesized gold from mercury with neutron bombardment using the cyclotron at Harvard University, but the isotopes of gold produced were all radioactive. In 1924, a German scientist, Adolf Miethe, reported achieving the same feat, but after various replication attempts around the world, it was deemed an experimental error. In 1980, Glenn Seaborg, K. Aleklett, and the Bevatron team transmuted several thousand atoms of bismuth into gold at the Lawrence Berkeley National Laboratory. His experimental technique using carbon-12 and neon-20 nuclei was able to remove protons and neutrons from the bismuth atoms. Seaborg's technique was far too expensive to enable the routine manufacture of gold but his work was then the closest yet to emulating an aspect of the mythical Philosopher's stone. In 2002 and 2004, CERN scientists at the Super Proton Synchrotron reported producing a minuscule amount of gold nuclei from induced photon emissions within deliberate near-miss collisions of lead nuclei. In 2022, CERN's ISOLDE team reported producing 18 gold nuclei from proton bombardment of a uranium target.
=== Economics === In 2008, it generated the tenth-highest amount of money for a medication in the U.S. in 2008, with sales exceeding $2.4 billion. To 2020, no study has examined the socioeconomic effects of utilization of pioglitazone.
Sources: en.wikipedia.org
=== Chemical laboratories === Laboratory glassware such as beakers and reagent bottles Weighing scale Laboratory scissor jack Fume hoods Reagents Analytical devices, such as: High-performance liquid chromatography spectrophotometers Liquid chromatography–mass spectrometry
== Method == Generally, negative ions are created (atoms are ionized) in an ion source. In fortunate cases, this already allows the suppression of an unwanted isobar, which does not form negative ions (as 14N in the case of 14C measurements). The pre-accelerated ions are usually separated by a first mass spectrometer of sector-field type and enter an electrostatic "tandem accelerator". This is a large nuclear particle accelerator based on the principle of a tandem van de Graaff accelerator operating at 0.2 to many million volts with two stages operating in tandem to accelerate the particles. At the connecting point between the two stages, the ions change charge from negative to positive by passing through a thin layer of matter ("stripping", either gas or a thin carbon foil). Molecules will break apart in this stripping stage. The complete suppression of molecular isobars (e.g. 13CH− in the case of 14C measurements) is one reason for the exceptional abundance sensitivity of AMS. Additionally, the impact strips off several of the ion's electrons, converting it into a positively charged ion. In the second half of the accelerator, the now positively charged ion is accelerated away from the highly positive centre of the electrostatic accelerator which previously attracted the negative ion. When the ions leave the accelerator they are positively charged and are moving at several percent of the speed of light. In the second stage of mass spectrometer, the fragments from the molecules are separated from the ions of interest.
== History == Inhibition of angiogenesis including VEGFR-2 inhibitors has been of much interest and research in recent decades because angiogenesis is required for tumors to grow beyond a diameter of 1–2 mm. Many small molecular drugs and biological macromolecules targeting VEGFRs or blocking signal transduction of VEGF/VEGFR have been approved for clinical use or entered clinical trials. In 2004 the monoclonal antibody bevacizumab became the first VEGFR inhibitor to be approved for cancer therapy. The first small molecular VEGFR-2 inhibitor to be approved was sunitinib in 2006.
Sources: en.wikipedia.org
=== EC 1.14.13 With NADH or NADPH as one donor, and incorporation of one atom of oxygen into the other donor === EC 1.14.13.1: salicylate 1-monooxygenase EC 1.14.13.2: 4-hydroxybenzoate 3-monooxygenase EC 1.14.13.3: Now EC 1.14.14.9, 4-hydroxyphenylacetate 3-monooxygenase EC 1.14.13.4: melilotate 3-monooxygenase EC 1.14.13.5: imidazoleacetate 4-monooxygenase EC 1.14.13.6: orcinol 2-monooxygenase EC 1.14.13.7: phenol 2-monooxygenase EC 1.14.13.8: flavin-containing monooxygenase EC 1.14.13.9: kynurenine 3-monooxygenase EC 1.14.13.10: 2,6-dihydroxypyridine 3-monooxygenase EC 1.14.13.11: Now EC 1.14.14.91, trans-cinnamate 4-monooxygenase EC 1.14.13.12: Now EC 1.14.14.92, benzoate 4-monooxygenase EC 1.14.13.13: Now classified as EC 1.14.15.18, calcidiol 1-monooxygenase EC 1.14.13.14: trans-cinnamate 2-monooxygenase EC 1.14.13.15: Now EC 1.14.15.15, cholestanetriol 26-monooxygenase EC 1.14.13.16: cyclopentanone monooxygenase EC 1.14.13.17: Now EC 1.14.14.23, cholesterol 7α-monooxygenase EC 1.14.13.18: 4-hydroxyphenylacetate 1-monooxygenase EC 1.14.13.19: taxifolin 8-monooxygenase EC 1.14.13.20: 2,4-dichlorophenol 6-monooxygenase EC 1.14.13.21: Now EC 1.14.14.82, flavonoid 3′-monooxygenase EC 1.14.13.22: cyclohexanone monooxygenase EC 1.14.13.23: 3-hydroxybenzoate 4-monooxygenase EC 1.14.13.24: 3-hydroxybenzoate 6-monooxygenase EC 1.14.13.25: methane monooxygenase (soluble) EC 1.14.13.26: Now classified as EC 1.14.18.4, phosphatidylcholine 12-monooxygenase EC 1.14.13.27: 4-aminobenzoate 1-monooxygenase EC 1.14.13.28: Now EC 1.14.14.93, 3,9-dihydroxypterocarpan 6a-monooxygenase EC 1.14.13.29: 4-nitrophenol 2-monooxygenase EC 1.14.13.30: Now EC 1.14.14.94, leukotriene-B4 20-monooxygenase EC 1.14.13.31: 2-nitrophenol 2-monooxygenase EC 1.14.13.32: albendazole monooxygenase EC 1.14.13.33: 4-hydroxybenzoate 3-monooxygenase (NAD(P)H) EC 1.14.13.34: leukotriene-E4 20-monooxygenase EC 1.14.13.35: anthranilate 3-monooxygenase (deaminating) EC 1.14.13.36: Now EC 1.14.14.96, 5-O-(4-coumaroyl)-D-quinate 3′-monooxygenase EC 1.14.13.37: Now EC 1.14.14.97, methyltetrahydroprotoberberine 14-monooxygenase EC 1.14.13.38: anhydrotetracycline monooxygenase EC 1.14.13.39: nitric-oxide synthase EC 1.14.13.40: anthraniloyl-CoA monooxygenase EC 1.14.13.41: Now EC 1.14.14.36, tyrosine N-monooxygenase EC 1.14.13.42: The activity is covered by EC 1.14.13.68, 4-hydroxyphenylacetaldehyde oxime monooxygenase EC 1.14.13.43: questin monooxygenase EC 1.14.13.44: 2-hydroxybiphenyl 3-monooxygenase EC 1.14.13.45: Now EC 1.14.18.2, CMP-N-acetylneuraminate monooxygenase EC 1.14.13.46: (-)-menthol monooxygenase EC 1.14.13.47: Now EC 1.14.14.99, (S)-limonene 3-monooxygenase EC 1.14.13.48: Now classified as EC 1.14.14.51, (S)-limonene 6-monooxygenase EC 1.14.13.49: Now classified as EC 1.14.14.52, (S)-limonene 7-monooxygenase EC 1.14.13.50: pentachlorophenol monooxygenase EC 1.14.13.51: 6-oxocineole dehydrogenase EC 1.14.13.52: Now EC 1.14.14.88, isoflavone 3′-hydroxylase EC 1.14.13.53: Now EC 1.14.14.89, 4′-methoxyisoflavone 2′-hydroxylase EC 1.14.13.54: ketosteroid monooxygenase EC 1.14.13.55: Now EC 1.14.14.98, protopine 6-monooxygenase EC 1.14.13.56: Now EC 1.14.14.100, dihydrosanguinarine 10-monooxygenase EC 1.14.13.57: Now EC 1.14.14.101, dihydrochelirubine 12-monooxygenase EC 1.14.13.58: benzoyl-CoA 3-monooxygenase EC 1.14.13.59: L-lysine N6-monooxygenase (NADPH) EC 1.14.13.60: Now included with EC 1.14.13.100, 25-hydroxycholesterol 7α-hydroxylase EC 1.14.13.61: 2-hydroxyquinoline 8-monooxygenase EC 1.14.13.62: 4-hydroxyquinoline 3-monooxygenase EC 1.14.13.63: 3-hydroxyphenylacetate 6-hydroxylase EC 1.14.13.64: 4-hydroxybenzoate 1-hydroxylase EC 1.14.13.65: deleted EC 1.14.13.66: 2-hydroxycyclohexanone 2-monooxygenase EC 1.14.13.67: Now EC 1.14.14.55, quinine 3-monooxygenase EC 1.14.13.68: Now EC 1.14.14.37, 4-hydroxyphenylacetaldehyde oxime monooxygenase EC 1.14.13.69: alkene monooxygenase EC 1.14.13.70: Now EC 1.14.14.154, sterol 14α-demethylase EC 1.14.13.71: Now EC 1.14.14.102, N-methylcoclaurine 3′-monooxygenase EC 1.14.13.72: Now classified as EC 1.14.18.9, methylsterol monooxygenase EC 1.14.13.73: Now EC 1.14.14.103, tabersonine 16-hydroxylase EC 1.14.13.74: Now EC 1.14.14.85, 7-deoxyloganin 7-hydroxylase EC 1.14.13.75: Now EC 1.14.14.104, vinorine hydroxylase EC 1.14.13.76: Now EC 1.14.14.105, taxane 10β-hydroxylase EC 1.14.13.77: Now EC 1.14.14.106, taxane 13α-hydroxylase EC 1.14.13.78: Now EC 1.14.14.86, ent-kaurene monooxygenase EC 1.14.13.79: Now EC 1.14.14.107, ent-kaurenoic acid oxidase EC 1.14.13.80: Now classified as EC 1.14.14.53, (R)-limonene 6-monooxygenase EC 1.14.13.81: magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase EC 1.14.13.82: vanillate monooxygenase EC 1.14.13.83: precorrin-3B synthase EC 1.14.13.84: 4-hydroxyacetophenone monooxygenase EC 1.14.13.85: Now EC 1.14.14.135, glyceollin synthase EC 1.14.13.86: The activity is covered by EC 1.14.14.87, 2-hydroxyisoflavanone synthase EC 1.14.13.87: Now EC 1.14.14.140, licodione synthase] EC 1.14.13.88: Now EC 1.14.14.81, flavanoid 3,5-hydroxylase EC 1.14.13.89: Now EC 1.14.14.90, isoflavone 2-hydroxylase EC 1.14.13.90: Now EC 1.14.15.21, zeaxanthin epoxidase EC 1.14.13.91: Now EC 1.14.14.136, deoxysarpagine hydroxylase EC 1.14.13.92: phenylacetone monooxygenase EC 1.14.13.93: Now EC 1.14.14.137, (+)-abscisic acid 8-hydroxylase EC 1.14.13.94: Now EC 1.14.14.138, lithocholate 6β-hydroxylase EC 1.14.13.95: Now included with EC 1.14.14.139, 5β-cholestane-3α,7α-diol 12α-hydroxylase EC 1.14.13.96: Now EC 1.14.14.139, 5β-cholestane-3α,7α-diol 12α-hydroxylase EC 1.14.13.97: Now EC 1.14.14.57, taurochenodeoxycholate 6α-hydroxylase EC 1.14.13.98: Now EC 1.14.14.25, cholesterol 24-hydroxylase EC 1.14.13.99: Now EC 1.14.14.26, 24-hydroxycholesterol 7α-hydroxylase EC 1.14.13.100: Now classified as EC 1.14.14.29, 25/26-hydroxycholesterol 7α-hydroxylase EC 1.14.13.101: senecionine N-oxygenase EC 1.14.13.102: Now EC 1.14.14.141, psoralen synthase EC 1.14.13.103: Now EC 1.14.14.142, 8-dimethylallylnaringenin 2-hydroxylase EC 1.14.13.104: Now EC 1.14.14.143, (+)-menthofuran synthase EC 1.14.13.105: monocyclic monoterpene ketone monooxygenase EC 1.14.13.106: now classified as EC 1.14.15.39, epi-isozizaene 5-monooxygenase. EC 1.14.13.107: limonene 1,2-monooxygenase EC 1.14.13.108: Now EC 1.14.14.144, abieta-7,13-diene hydroxylase EC 1.14.13.109: Now EC 1.14.14.145, abieta-7,13-dien-18-ol hydroxylase EC 1.14.13.110: Now EC 1.14.14.146, geranylgeraniol 18-hydroxylase EC 1.14.13.111: methanesulfonate monooxygenase EC 1.14.13.112: Now EC 1.14.14.147, 3-epi-6-deoxocathasterone 23-monooxygenase EC 1.14.13.113: FAD-dependent urate hydroxylase EC 1.14.13.114: 6-hydroxynicotinate 3-monooxygenase EC 1.14.13.115: Now EC 1.14.14.148, angelicin synthase EC 1.14.13.116: Now EC 1.14.14.174, geranylhydroquinone 3-hydroxylase EC 1.14.13.117: Now EC 1.14.14.39, isoleucine N-monooxygenase EC 1.14.13.118: Now EC 1.14.14.38, valine N-monooxygenase EC 1.14.13.119: Now EC 1.14.14.149, 5-epiaristolochene 1,3-dihydroxylase EC 1.14.13.120: Now EC 1.14.14.150, costunolide synthase EC 1.14.13.121: Now EC 1.14.14.151, premnaspirodiene oxygenase EC 1.14.13.122: chlorophyllide-a oxygenase EC 1.14.13.123: Now EC 1.14.14.95, germacrene A hydroxylase EC 1.14.13.124: now classified as EC 1.14.14.40, phenylalanine N-monooxygenase EC 1.14.13.125: Now EC 1.14.14.156, tryptophan N-monooxygenase EC 1.14.13.126: Now EC 1.14.15.16, vitamin D3 24-hydroxylase EC 1.14.13.127: 3-(3-hydroxyphenyl)propanoate hydroxylase EC 1.14.13.128: 7-methylxanthine demethylase EC 1.14.13.129: Now EC 1.14.15.24, β-carotene 3-hydroxylase EC 1.14.13.130: pyrrole-2-carboxylate monooxygenase EC 1.14.13.131: dimethyl-sulfide monooxygenase EC 1.14.13.132: Now EC 1.14.14.17, squalene monooxygenase EC 1.14.13.133: Now EC 1.14.15.32, pentalenene oxygenase EC 1.14.13.134: Now EC 1.14.14.152, β-amyrin 11-oxidase EC 1.14.13.135: 1-hydroxy-2-naphthoate hydroxylase EC 1.14.13.136: Now EC 1.14.14.87, 2-hydroxyisoflavanone synthase EC 1.14.13.137: Now EC 1.14.14.153, indole-2-monooxygenase EC 1.14.13.138: Now EC 1.14.14.157, indolin-2-one monooxygenase EC 1.14.13.139: Now EC 1.14.14.109, 3-hydroxyindolin-2-one monooxygenase EC 1.14.13.140: Now EC 1.14.14.110, 2-hydroxy-1,4-benzoxazin-3-one monooxygenase. EC 1.14.13.141: Now EC 1.14.15.29, cholest-4-en-3-one 26-monooxygenase [(25S)-3-oxocholest-4-en-26-oate forming] EC 1.14.13.142: Now EC 1.14.15.30, 3-ketosteroid 9α-monooxygenase EC 1.14.13.143: Now EC 1.14.14.76 ent-isokaurene C2/C3-hydroxylase EC 1.14.13.144: Now EC 1.14.14.111, 9β-pimara-7,15-diene oxidase EC 1.14.13.145: Now EC 1.14.14.112, ent-cassa-12,15-diene 11-hydroxylase EC 1.14.13.146: taxoid 14β-hydroxylase EC 1.14.13.147: Now EC 1.14.14.182, taxoid 7β-hydroxylase EC 1.14.13.148: trimethylamine monooxygenase EC 1.14.13.149: phenylacetyl-CoA 1,2-epoxidase EC 1.14.13.150: Now EC 1.14.14.113, α-humulene 10-hydroxylase EC 1.14.13.151: Now EC 1.14.14.84, linalool 8-monooxygenase EC 1.14.13.152: Now EC 1.14.14.83, geraniol 8-hydroxylase EC 1.14.13.153: (+)-sabinene 3-hydroxylase EC 1.14.13.154: erythromycin 12-hydroxylase EC 1.14.13.155: α-pinene monooxygenase EC 1.14.13.156: Now EC 1.14.14.133, 1,8-cineole 2-endo-monooxygenase EC 1.14.13.157: Now EC 1.14.14.56, 1,8-cineole 2-exo-monooxygenase EC 1.14.13.158: Now EC 1.14.14.114, amorpha-4,11-diene 12-monooxygenase EC 1.14.13.159: Now EC 1.14.14.24, vitamin D 25-hydroxylase EC 1.14.13.160: (2,2,3-trimethyl-5-oxocyclopent-3-enyl)acetyl-CoA 1,5-monooxygenase EC 1.14.13.161: (+)-camphor 6-exo-hydroxylase EC 1.14.13.162: Now EC 1.14.14.108, 2,5-diketocamphane 1,2-monooxygenase EC 1.14.13.163: 6-hydroxy-3-succinoylpyridine 3-monooxygenase EC 1.14.13.164: withdrawn: see EC 1.13.11.65, carotenoid isomerooxygenase EC 1.14.13.165: Now classified as EC 1.14.14.47, nitric-oxide synthase (flavodoxin) EC 1.14.13.166: 4-nitrocatechol 4-monooxygenase EC 1.14.13.167: 4-nitrophenol 4-monooxygenase EC 1.14.13.168: indole-3-pyruvate monooxygenase EC 1.14.13.169: Now EC 1.14.18.5, sphingolipid C4-monooxygenase EC 1.14.13.170: pentalenolactone D synthase EC 1.14.13.171: neopentalenolactone D synthase EC 1.14.13.172: salicylate 5-hydroxylase EC 1.14.13.173: Now EC 1.14.14.115, 11-oxo-β-amyrin 30-oxidase EC 1.14.13.174: Now EC 1.14.14.116, averantin hydroxylase EC 1.14.13.175: Now EC 1.14.14.117, aflatoxin B synthase EC 1.14.13.176: Now EC 1.14.14.118, tryprostatin B 6-hydroxylase EC 1.14.13.177: Now EC 1.14.14.119, fumitremorgin C monooxygenase EC 1.14.13.178: methylxanthine N1-demethylase EC 1.14.13.179: methylxanthine N3-demethylase EC 1.14.13.180: aklavinone 12-hydroxylase EC 1.14.13.181: 13-deoxydaunorubicin hydroxylase EC 1.14.13.182: 2-heptyl-3-hydroxy-4(1H)-quinolone synthase EC 1.14.13.183: Now EC 1.14.14.120, dammarenediol 12-hydroxylase EC 1.14.13.184: Now EC 1.14.14.121, protopanaxadiol 6-hydroxylase EC 1.14.13.185: Now EC 1.14.15.33, pikromycin synthase EC 1.14.13.186: Now EC 1.14.15.34, 20-oxo-5-O-mycaminosyltylactone 23-monooxygenase EC 1.14.13.187: L-evernosamine nitrososynthase EC 1.14.13.188: Now EC 1.14.15.35, 6-deoxyerythronolide B hydroxylase EC 1.14.13.189: 5-methyl-1-naphthoate 3-hydroxylase EC 1.14.13.190: Now EC 1.14.14.175, ferruginol synthase EC 1.14.13.191: Now EC 1.14.14.70, ent-sandaracopimaradiene 3-hydroxylase EC 1.14.13.192: Now EC 1.14.14.122, oryzalexin E synthase EC 1.14.13.193: Now EC 1.14.14.123, oryzalexin D synthase EC 1.14.13.194: Now EC 1.14.14.78, phylloquinone ω-hydroxylase EC 1.14.13.195: L-ornithine N5-monooxygenase (NADPH) EC 1.14.13.196: L-ornithine N5-monooxygenase [NAD(P)H] EC 1.14.13.197: Now EC 1.14.14.124, dihydromonacolin L hydroxylase EC 1.14.13.198: Now EC 1.14.14.125, monacolin L hydroxylase EC 1.14.13.199: Now EC 1.14.14.79, docosahexaenoic acid ω-hydroxylase EC 1.14.13.200: tetracenomycin A2 monooxygenase-dioxygenase EC 1.14.13.201: Now EC 1.14.14.126, β-amyrin 28-monooxygenase EC 1.14.13.202: Now EC 1.14.14.127, methyl farnesoate epoxidase EC 1.14.13.203: Now EC 1.14.14.128, farnesoate epoxidase EC 1.14.13.204: Now EC 1.14.14.129, long-chain acyl-CoA ω-monooxygenase EC 1.14.13.205: Now EC 1.14.14.80, long-chain fatty acid ω-monooxygenase EC 1.14.13.206: Now EC 1.14.14.130, laurate 7-monooxygenase EC 1.14.13.207: Now EC 1.14.14.31, ipsdienol synthase EC 1.14.13.208: benzoyl-CoA 2,3-epoxidase EC 1.14.13.209: salicyloyl-CoA 5-hydroxylase EC 1.14.13.210: 4-methyl-5-nitrocatechol 5-monooxygenase EC 1.14.13.211: rifampicin monooxygenase EC 1.14.13.212: 1,3,7-trimethyluric acid 5-monooxygenase EC 1.14.13.213: Now EC 1.14.14.131, bursehernin 5-monooxygenase EC 1.14.13.214: Now EC 1.14.14.132, (–)-4′-demethyl-deoxypodophyllotoxin 4-hydroxylase EC 1.14.13.215: protoasukamycin 4-monooxygenase EC 1.14.13.216: asperlicin C monooxygenase EC 1.14.13.217: protodeoxyviolaceinate monooxygenase EC 1.14.13.218: 5-methylphenazine-1-carboxylate 1-monooxygenase EC 1.14.13.219: resorcinol 4-hydroxylase (NADPH) EC 1.14.13.220: resorcinol 4-hydroxylase (NADH) EC 1.14.13.221: Now EC 1.14.15.28, cholest-4-en-3-one 26-monooxygenase [(25R)-3-oxocholest-4-en-26-oate forming] EC 1.14.13.222: aurachin C monooxygenase/isomerase EC 1.14.13.223: 3-hydroxy-4-methylanthranilyl-[aryl-carrier protein] 5-monooxygenase EC 1.14.13.224: violacein synthase EC 1.14.13.225: F-actin monooxygenase EC 1.14.13.226: acetone monooxygenase (methyl acetate-forming) EC 1.14.13.227: propane 2-monooxygenase EC 1.14.13.228: jasmonic acid 12-hydroxylase EC 1.14.13.229: tert-butyl alcohol monooxygenase EC 1.14.13.230: butane monooxygenase (soluble) EC 1.14.13.231: tetracycline 11a-monooxygenase EC 1.14.13.232: 6-methylpretetramide 4-monooxygenase EC 1.14.13.233: 4-hydroxy-6-methylpretetramide 12a-monooxygenase EC 1.14.13.234: 5a,11a-dehydrotetracycline 5-monooxygenase EC 1.14.13.235: indole-3-acetate monooxygenase EC 1.14.13.236: toluene 4-monooxygenase EC 1.14.13.237: aliphatic glucosinolate S-oxygenase EC 1.14.13.238: dimethylamine monooxygenase EC 1.14.13.239: carnitine monooxygenase EC 1.14.13.240: 2-polyprenylphenol 6-hydroxylase EC 1.14.13.241: 5-pyridoxate monooxygenase EC 1.14.13.242: 3-hydroxy-2-methylpyridine-5-carboxylate monooxygenase EC 1.14.13.243: toluene 2-monooxygenase EC 1.14.13.244: phenol 2-monooxygenase (NADH) EC 1.14.13.245: assimilatory dimethylsulfide S-monooxygenase EC 1.14.13.246: 4β-methylsterol monooxygenase EC 1.14.13.247: stachydrine N-demethylase
== Diagnosis == The most conclusive test for a patient with a potential neurofibrosarcoma is a tumor biopsy (taking a sample of cells directly from the tumor itself). MRIs, X-rays, CT scans, and bone scans can aid in locating a tumor and/or possible metastasis.
== History == No clear record of the breed's origin exists. They are most often claimed to have originated as the companions of temple priests in northern Burma in the Mount of Lugh. Many stories exist of how the cats first came to France, including pairs of cats being given as a reward for helping defend a temple, or being smuggled out of Burma and Sweden by a Vanderbilt. Another pair of Birmans (or a pregnant female called Poupée de Maldapour) were said to have been stolen and later imported to France by Thadde Haddisch. The first traces of historical Birmans go back to a Mme Leotardi in Nice, France. Birmans were almost wiped out as a breed during World War II. Only two cats were alive in Europe at the end of the war, a pair named Orloff and Xenia de Kaabaa, both belonging to Baudoin-Crevoisier. The foundation of the breed in postwar France were offspring of this pair. They had to be heavily outcrossed with long-hair breeds such as Persian and Siamese to rebuild the Birman breed. By the early 1950s, pure Birman litters were again being produced. The restored breed was recognized in Britain in 1965 and by the Cat Fanciers' Association (CFA) in 1966. The first Birman cats were seal point. The blue point colour was introduced in 1959 using blue Persian lines. New colours were later added by English breeders including chocolate, red, and tabby/lynx points. Birmans have also been used in the development of new breeds such as the Ragdoll.
Sources: en.wikipedia.org
HPLC testing measures the presence and amount of one or more compounds in a liquid sample. It separates mixture components and records detector responses as peaks, which are compared with reference standards. Results are usually reported as concentrations or relative percentages.
Retention time is the interval between sample injection and the detector response for a given compound. It depends on the compound's interactions with the stationary and mobile phases under set conditions. Matching a retention time to a standard supports tentative identification but is not always unique.
HPLC alone can separate unknown compounds and provide retention times, but it often cannot identify them with certainty. Coupling HPLC to mass spectrometry gives mass information that improves identification. Confirmation usually requires comparison with reference standards or complementary techniques.
System suitability is a set of checks that confirm the instrument and method perform within limits before sample analysis. It typically includes resolution, tailing factor, retention time, and peak area reproducibility. If a check fails, the run is invalidated until the cause is resolved.