Clinical Chemistry Exam 1 (Ch. 5, 6, 7, 10)

what is one advantage and one disadvantage for fluorometry?

-advantage: very specific since you can choose a particular wavelength -disadvantage: sensitive to environmental changes (ex. pH or temp)

what is the formula for calculating %T? what is the formula for calculating Abs from %T?

-%T = (T / I) x 100 -Abs = 2-log(%T)

What are some examples of POCT users? (10)

-ER -OR -ICU -Clinics -physician offices -nursing homes -pediatric units -pharmacies -counseling centers -ambulances

How is Beer's law applied in spectrophotometry?

-a beam of light enters the solution -some light is absorbed -remainder passes through and strikes a detector -detector converts to electric signal -gets % trasnmittance

what is a standard ?

-a sample in which the concentration of the analyte is already known -used to be compared to your unknown -standard should be analyzed the same way you analyze the unknown

Describe the signal processing and data handling - why is calibration essential?

-accurate calibration is essential to obtaining accurate info -multiple instruments that measure the same constituent in a lab should be calibrated so that results are compatible -automated instruments, once calibrated, provide long-term stability of standard curve; require only monitoring -some instruments are self calibrating -advanced automated instruments have method of reporting printed results -computerized monitoring is available for many parameters

What is Beer's Law?

-analyses the relationship between absorption of light by a solution and the concentration of the solution -the concentration of the substance is inversely proportional to the logarithm of light transmitted -the concentration of the substance is directly proportional to the amount of light absorbed

What is the pre-analytic phase (sample processing) of automation? what are the 5 key components?

-automated process replaced manual handling **KEY COMPONENTS: -conveyance system -bar coded specimens -computer software package to control specimen movement -coordination of robots with instruments as work cells -automated sorting, centrifugation, uncapping, sample archiving, aliquoting

What are 4 issues to consider when implementing a new POCT?

-average turnaround time and cost for testing in lab vs. POCT -impact on length of stay or patient satisfaction -impact on operational efficiency for department -options for achieving objectives other than POCT

What is the post-analytic phase (data management) of automation? (4)

-bidirectional communication between analyzers and host computer -integration of work station managers into communication system -automated management of quality control data -user-defined perimeters for many values

Which layer can physical or chemical reactions occur in dry slides? what happens to the byproducts from the previous layer?

-both can occur in one layer (central) and product passes to the next where other reactions occur until the final layer (indicator layer) -byproducts will stay behind since they are no necessary for the subsequent layer

How is quality assurance applied for spectrophotometry? (3) - how is calibration done? how is stray light detected?

-calibration: wavelength accuracy; verify that the wavelength on the control dial is the actual wavelength of light passed by the monochromator; useing standard absorbing solns or filters with known wavelength of max absorbance -stray light: any wavelength outside the band transmitted by the monochromator; caused by dust particles or scratches; detected using cutoff filters that eliminate all radiation at wavelength beyond one of interest -linearity

What is chemiluminescence? what type of reaction does this occur through ? what is measured? light signal is related to what?

-chemical reaction that produces light without heat -oxidation reactions (loses electrons) -emitted radiation is measured: light signal is related to analyte concentration

Describe specimen measurement and delivery - what 2 things can hold specimen containers? what tubes are placed in carousels or racks? how is aliquot measured and put into a probe? probe and tubing are what after each dispensing? can be avoided if what?

-circular carousels or rectangular racks hold specimen containers -primary collection tubes or microsample tubes are placed in carousels or racks -aliquot is measured through aspiration of sample into a probe -probe and tubing are cleaned each dispensing to minimize carryover, unless disposable probes or tips are used

What are the accuracy requirements for POCT? (6)

-comparisons to central laboratory -harmonization and standardization -daily QC -proficiency testing -user competency testing -management of user records

What are some desirable characteristics of POCT analyzers? (9)

-ease of use -method of accuracy and comparability to lab's methods -portability -durability -low maintenance -simple QC -simple sample handling -barcode (patient ID and user ID) -ability to interface with LIS

What are some examples of POC tests? (12)

-electrolytes -glucose -hemoglobin AIC -pregnancy -drugs of abuse -occult blood -blood gases -cardiac markers -HIV -gonorrhea -syphilis -influenza

Describe 2 types of sample introduction and ionization in mass spectrometry

-electron ionization: most commonly used; where you apply electricity to ionize the sample; sample is bombarded with electrons resulting in charged sample -atmospheric pressure ionization: conducted during specific pressure to charge sample

what are the mass analyzer and the detector components of mass spectrometry considered?

-electron multipliers: ions of sample strike a node causing a chain reaction where electrons are emitted; electrons attracted to another node causing a ripple effect

How do you implement a POCT (what do you need to establish)?

-establish a need -handling a request for new or additional POCT -document request via standardized form -evaluate request using program structure -consider whether comparable testing is available in central clinical lab

What is the analytic phase (chemical analyses) of automation? (6)

-ever smaller microsampling -expanded onboard and total test menus -accelerated reaction times -higher resolution optics -improved flow through electrodes -enhanced user-friendly interactive software for quality control, maintenance, and diagnostics -ergonomic and physical design improvements

What are some advantages of POCT? (5)

-fast delivery of results (MAJOR) -pediatric population: only a small amount required -cost -fewer pre-analytic and post-analytic errors -portability: rural areas, accident sites, areas with limited infrastructure and personnel, and low resource communities

What is centrifugal analysis? capable of what analysis?

-force of centrifugation transfers and contains liquid (reagents are liquids) -capable of batch analysis

What do single-use quantitative cartridge/strip tests with a reader device analyze? (12)

-glucose -blood chemistry -coagulation -cardiac markers -drugs -CRP -allergy -fertility -chlamydia -HbA1c -urine albumin -pH, blood gases, electrolytes, metabolites

What are several types of POCT analyzers? (5)

-glucose (HIGHEST VOLUME) -blood chemistry -coagulation -cardiac markers -HbA1c -others

What do multiple-use quantitative cartridge/benchtop devices analyze? (4)

-hemoglobin species, bilirubin -pH, blood gases, electrolytes, metabolites -cardiac markers, drugs, CRP -complete blood count

what is one use for electrophoresis ?

-in clinical chemistry for proteins in urine and CSF

What are the 4 basic components of mass spectrometry?

-sample inlet -ionization source (where actual sample is vaporized and charged) -mass analyzer -ion detector

Describe QC and proficiency testing in POCT (4) - validation of what? ensure what? what is internal and external QC?

-insure quality of results -validation of analytical performance and limitations of assay -some have internal and external QC -internal QC: electronics are performing as expected -external QC: controls are used

What are the 6 components for a fluorometer?

-light source -attenuator -primary filter -sample -secondary filter -detector (set at an angle so initial light source will not interfere with light emitted from sample)

What are the 4 components of the spectrophotometer? describe the funciton of each.

-light source (incandescent tungsten or tubgsten iodide) -monochromators: isolate individual wavelength of light, simple glass prism, gratings are most commonly used -sample cell: cuvette where sample is placed -photodetectors: converts the transmitted radiant energy into an equivalent amount of electrical energy; photocell, phototube, photomultiplier

Describe reagent systems and delivery - what are 2 ways that reagent can come? what does preservation of reagents depend on? how are most dry reagents preserved? what happens to expiration date once open container or reconstitute dry reagent?

-liquid: available in bulk volume containers or unit doses --> dispensed via tubing from bulk containers, syringes that pipette reagents into reaction containers, piston-driven pumps connected by tubing or pressurized reagent bottles -dry: bottled as lyophilized powder, requiring reconstitution --> multilayered dry chemistry slide **preservation: refrigeration, reconstitution of dry tablet, or combination of two stable components

What is continuous flow?

-liquids are pumped through system of continuous tubing -samples are introduced in a sequential manner from a bulk container of reagent; flow of reagent is continuous and may be separated btw samples

What are waived tests? what are 3 examples?

-lowest level of regulation -cleared by FDA for home use (error will not cause risk of harm to patient) -Defined by CLIA as: --dipstick tests --urine pregnancy tests --blood glucose monitoring devices

Spectrophotometry - what is it? instrument measures what? what is the principle (what happens when light passes through an object)?

-measurement of light at a selected wavelength -instruments measure light intensity, using filters to select the incident wavelength -principle: light passes through an object will be partially reflected, absorbed, and transmitted

What is a atomic absorption spectrophotometer? what is it used for?

-measures concentration by detecting the absorption of electromagnetic radiation by atoms instead of molecules -used to measure concentration of trace metals

what does a spectrophotometer do?

-measures light that is transmitted by a solution to determine the concentration of the substance in the solution; analyte absorbs light which is directly proportional to the concentration

What are the common applications of turbidimetry? (3)

-microbiology: checks for bacterial growth in cultures (broth) -coagulation (measures clot formation) -clinical chemistry (to quantify protein conc. in fluids)

What is isoelectric focusing?

-modification of electrophoresis -separation proteins by charge -charged proteins migrate through a support medium that has a continuous pH gradient -proteins move in the electric field until they reach their isoelectric point (no charge); no charge means it cannot move since nothing is pulling/driving it

What are some future trends in automation? (6)

-more integration and miniaturization of operating systems -more sophisticated portable analyzers -new tests for expanded menus -spectral mapping, multiple wavelength monitoring, with high resolution photometers in analyzers -extensive use of mass spectrometry and capillary electrophoresis -system and workflow integration with robotics and data management

What are dry slides? and what are the 3 layers? (Vitros 250/350- Ortho Clinical Diagnostics? layers vary depending on? color development of indicator layer varies with?

-multiple slides/layers mounted on plastic support 1. spreading layer: accepts sample 2. central layer: aliquot alterations 3. indicator layer: analyte of interest is quantified -layers vary depending on test -color development of indicator varies with concentration -->high conc of analyte = darker color -->low conc. of analyte = lighter color

Describe moderate and high complexity tests

-must fulfill all requirements and standards from accrediting agencies -skillful and accredited personnel

What should you consider when selecting an automated analyzer? (5)

-not only the cost of actual instrument but all associated consumables (calculate the total cost per test for each instrument) -perform break-even analysis on relationship of fixed costs, variable costs, and profits -factor in mode of acquisition (purchase, lease, rent) -consider analytic capabilities of instrument--can the instrument expand its testing menu? -observe instrument in operation on trail basis

What are the sources of error in turbidimetry? (3)

-particles aggregate and settle-specimen handling is important -particle size of standard not the same as the sample -need to mix well

What are pH electrodes? what are 5 types of electrodes that can be used?

-potentiometry principle; measurement of electrical potential due to activity of free ions 1. ion selective electrode 2. reference electrode 3. indicator electrode: when placed in the solution to be tested, hydrogen ions move and produce a potential difference 4. gas sensing electrodes 5. enzyme electrodes

What are the components of electrophoresis? (3)

-power supply -buffer -support material: cellulose acetate, aragose gel, polyacrylamide gel, and starch gel

What 7 methodologies do POCT utilize?

-reflectance -electrochemistry -immunoturbidity -lateral flow, flow-through, solid phase -spectrophotometry -fluorescence -PCR

What are the steps in preliminary selection of device/methods? (5)

-review options and limit selection to several methods/instruments -perform literature search for data on performance of method/instrument -contact other users for references, sharing of validation data -perform preliminary, limited validation, including mini correlation -select method/instrument

Describe ion exchange chromatography - what is the stationary phase? if you are looking for a positively charged protein in sample, then resin in stationary phase should have what charged on beads? what is it called if resin is negative? what is it called if resin is positive? what happens to charged polymers in the resin? what are some uses for this separation?

-separation based on size and charge -stationary phase: resin-insoluble in water-charged polymers immobilized in the resin; resin can be of benzene, silicates, or cellulose -negative charge -anion beads/resin (negatively charged); anion exchange chromatography -cation beads/ resin (positively charged); cation exchange chromatography -to remove interfering substances from solution, to concentrate dilute solutions, and to separate mixtures with charged molecules

Describe size exclusion chromatography - what is the column packed with? what happens after the sample is dissolved in mobile phase? what happens to small molecules? what happens to medium molecules? what happens to large molecules ? what early methods used to be used for pores? what current methods are used for pores

-separation based on size and shape of molecules -column packed with porous material -sample: dissolved in mobile phase, moves down column -small molecules enter the pores, large molecules move down the column faster, and medium molecules enter the pores partially (they move slower than the large molecules); hydrophilic beads of polyacrylamide or agarose or hydrophobic beads of polystyrene; now we use rigid inorganic material like silica or glass for pore separation

What is discrete analysis

-separation of each sample and reagent in a separate container; eliminates cross contamination -most popular type; can run multiple tests on one sample at a time or multiple samples one test at a time

What are the applications of mass spectrometry? (8)

-small molecule analysis -structural information -molecular weight determination -measuring drugs or abuse-urine toxicology -drugs and metabolites must be extracted from body fluids and mixed with reagents to form volatile compounds -proteomics and pathogen identification -Maldi-Tof: identification of protein samples in pathogen identification -Plex-ID -Point of care

in nephelometry if light scatter is related to the number and size of particles, describe the light scatter in the following: -small particle size -large particle size -small number of particles -large number of particles

-small particle size = little light scatter -large particle size = large light scatter -small number of particles = less light scatter -large number of particles = more light scatter

What is the procedure for thin layer chromatography? what are the stationary and mobile phases? why is it important that solvent/mobile phase only cover half sample? what do you compare samples to? what is the retention factor?

-thin layer of sorbent placed on a glass or plastic plate-stationary phase -sample to be analyzed placed in spot near one edge of plate -mobile phase-solvent: in closed container (MOBILE PHASE SHOULD NOT COVER SAMPLE) -plate is placed in solvent -solvent migrates upward through capillary action -after solvent reaches a determined height on the plate, plate is removed and dried -samples components are identified by comparing them with standards on the same plate -retention factor (Rf)-distance a component migrates compared with the distance the solvent moves **distance the sample migrates/distance solvent moves**

What does single use, qualitative, or semiquantitative cartridge/strip tests analyze? (3)

-urine and blood chemistry -infectious disease agents -cardiac markers hCG

What is calibration? calibrators have set concentrations for what? can be used to create linear relationship btw what? are monitored by controls how often? what happens if an unknown exceeds the concentration of the standard/calibrator?

-used to align the signal strength of an instrument to a particular concentration of an analyte -calibrators have precisely set concentrations and are specific for analytes --some are used to create linear relationship between signal strength and concentration -can be monitored by controls daily -most analyzer retain calibration per lot -if concentration of an unknown exceeds the concentration of the standard/calibrator the instrument will flag

we normally use what type of light in spectrophotometry and what is its wavelength range?

-visible light, UV light, infrared light -350-800 nm (in visible light)

What happens in the chemical reaction phase in terms of mixing? what are 3 ways mixing can occur?

1. Mixing of reagents and sample -coiled tubing (continuous flow analyzers) -dry slides: spreading layer (rapid and uniform spreading) -automated wet analyzers-paddles that enter the reaction container, mix and exit

what are 4 modes of separation in chromatography?

1. adsorption chromatography 2. partition chromatography 3. size exclusion chromatography 4. ion exchange chromatography

What are the driving forces toward more automation? (4)

1. higher volume of testing, faster turnaround time 2. regulatory standards requiring greater accuracy and precision 3. intense competition among instrument manufacturers 4. decreased operating budgets for labs, ability to "walk away"

What are the advantages of automation? (5)

1. increases number of tests performed in a lab 2. decreases labor and cost per test 3. minimizes variation in results among laboratorians 4. eliminates potential errors of manual analyses 5. instruments use very small amounts of samples and reagents

What are the three recent advances in automation?

1. point of care benchtop analyzers -small, portable, easy to operate -used in primary in physician office laboratories, surgical and critical care units 2. immunochemistry -assaying drugs, specific proteins, tumor markers, hormones -instruments using fluorescence polarization immunoassay, nephelometry, and immunoassay with chemiluminescent detection 3. Modular Assays -combination of chemistry and immunoassay

What is the POCT checklist? (7)

1. quality management: there is a written QM program as well as organizational system setting forth levels of authority, responsibility and accountability 2. specimen handling: there is a documented procedure describing methods for patient identification and preparation, as well as for specimen collection, accessioning, and preservation before testing 3. reagents: all reagents should be stored and labeled 4. instruments and equipment: equipment must be evaluated and scheduled for a regular maintenance 5. personnel: testing personnel have adequate, specific training to ensure competence 6. quality control and calibration: calibrations and QCs are run at regular intervals for control procedures 7. safety: there is a program to assure that the safety of patients and health care personnel is not compromised by POCT

what are the 4 basic disciplines (techniques) of analytic chemistry ?

1. spectrometry 2. luminescence 3. electroanalytic methods 4. chromatography

What are the personnel requirements for POCT? who are the 3 support staff and what are their responsibilities?

1. support staff -director: PhD, MD, or DO laboratory scientist or pathologist -responsibilities: policy, admin, financial, and technical decisions 2. point of care coordinator: -implementing and coordinating POCT, facilitating compliance with procedures, policies, regulations 3. designated contacts or trainers in non-laboratory departments -facilitate efficient POCT program, serve as link between coordinator and staff, ease training

What are the three testing complexity categories?

1. waived testing 2. moderately complex testing 3. high complex testing

administration and structure for POCT - all testing falls within what agencies guidelines? what 2 organizations enforce CLIA 88? each level of testing complexity must have what to perform ?provider performed microscopy needs what?

CLIA; -all testing, including POCT falls within scope of CLIA regulation -FDA and CMS oversee and enforce CLIA 88 -CLIA license must match level of testing complexity being done -provider-performed microscopy testing has special requirements

What is reflectance spectrophotometry? the amount of what is read after light passes through indicator layer? light is reflected at a 45 degree angle to what slide/layer? what does the photocell detector measure?

The method used by most dry-chemistry analyzers to determine concentration of an analyte; -amount of chromagen is read after light passes through the indicator layer, reflecting into a detector -light reflected by a mirror at a 45 degree angle to the bottom of the slide (INDICATOR LAYER) -photocell detector: detects the reflected light from the indicator level

What is mass spectrometry? is this technique definitive? what 2 things must be done to sample before detection occurs? fragments are separated according to what ratio? what does the detector measure? molecule identification is based on?

a technique that separates particles according to their mass -definitive identification of samples -sample is volatilized and then ionized to form charged molecular ions and fragments that are separated according to mass/charge ratio -detector: measure intensity of ion current for each species -molecule identification: based on formation of characteristic fragments

What is absorbance in spectrophotometry? can it be measured directly? how is it derived? Abs is directly proportional to? what is the formula for Abs using a, b, and c?

amount of light absorbed by the sample; -cannot be measured directly -mathematically derived from %T -absorbance is directly proportional to concentration -A= abc (a)= molar absorptivity (b): length of light through the solution (c): concentration of absorbing molecules

What is point of care testing?

analytical patient-testing activities provided within the institution, but performed outside the physical facilities of the clinical laboratories -usually administered by the lab -often performed by non-laboratory personnel

What happens in the chemical reaction phase in terms of reaction time?

depends on rate of transport through system and timed reagent additions

What are gas sensing electrodes? describe a pCO2 electrode and a NH3 (ammonia) electrode

designed to detect specific gases in solution -pCO2 electrode: membrane in contact with the solution is permeable only to CO2; CO2 diffuses into a thin film of sodium bicarbonate solution; pH of the solution changes and detected by pH electrode -NH3 electrode: membrane is permeable only to ammonia

What is fluorometry and fluorescence?

fluorescence: a molecule absorbs light at one wavelength and re-emits light a lower wavelength; -the light entering the solution may pass through or it may be absorbed -measures the energy emitted by the molecules

What happens in the chemical reaction phase in terms of incubation?

heating bath (water or air) to maintain required temperature of reaction mixture

What are enzyme electrodes?

ion selective electrodes covered with enzymes that can catalyze a specific chemical reaction; this reaction is how you measure the enzyme

Certificate of compliance

issued to a laboratory after an inspection that finds the laboratory to be in compliance with all applicable CLIA requirements

Certificate for PPMPs (provider performed microscopy procedure)

issued to a laboratory in which a physician, midlevel practitioner, or dentist performs no tests other than the microscopy procedures -permits the laboratory to also perform waived tests

Certificate of Accreditation? approved by who? (HCFA)

issued to a laboratory on the basis of the laboratory's accreditation by an accreditation organization approved by the health care finance administration

Certificate of registration

issued to a laboratory that enables the entity to conduct moderate-to-high complexity laboratory testing or both until the entity is determined by survey to be in compliance with CLIA regulations

Certificate of waiver

issued to a laboratory to perform only waived tests

What is high performance liquid chromatography? what are the 5 components?

it uses: -pressure for fast separation -controlled temperature -gradient elution techniques components: -pumps (force the mobile phase through the column) -columns -sample injectors -detectors -recorders

What is nephelometry? (SCATTERED) light is measured at an? light scatter depends on what 2 things?

measures the amount of scattered light by particles in a sample -measured at an angle to the incident light on cuvette -light scatter depends on wavelength and particle size

What is osmometry and osmolality? what happens to any substance dissolved in a solution? what are 4 ways that the solution will change? what does the osmometer measure (directly or indirectly)?

osmolality: measures the concentration of dissolved particles in a solution -any substance dissolved in a solution will change the physical properties of that solution: boiling point increases, decreases freezing point, osmotic pressure increases, and decrease vapor pressure -measures osmolality indirectly by measuring one of the physical properties (boiling point, freezing point, osmotic pressure, or vapor pressure

What is automation?

permits the labratorian to focus on processes that need to be performed manually -provides efficient testing

What is a analyte in spectrophotometry? what is the difference in amount of light transmitted by blank and sample due to? what should %T be?

sample; -absorbing molecules to be measured -placed in solvent, in cuvette, placed in light path -difference in amount of light transmitted by the blank and the sample is due to analyte -%T is going to be lower than blank

What happens in the chemical reaction phase in terms of separation?

separating undesirable substances from sample

describe adsorption chromatography - which molecules move fastest? and which move slowest? what is the mobile phase? what 3 types can the stationary phase be?

separation based on competition between sample and mobile phase for adsorptive sites on stationary phase -most soluble molecules in the mobile phase move faster (can mix) -least soluble molecules in the mobile phase move slower (can't mix) -MOBILE PHASE: single solvent or mixture of solvents -STATIONARY: acidic polar, basic polar, non-polar

Describe partition chromatography - when the 2 phases are separated, where do the polar and non-polar molecules go? what is the partition coefficient?

separation based on solubility of solute in polar or non-polar solvents; -molecules containing polar and non-polar groups are added to an organic solvent -vigorous shaking -2 phases are separated: polar molecules stain in aqueous solvent and non polar molecules are extracted in organic solvent -partition coefficient: ratio of concentration of the solute in the 2 liquids

What is electrophoresis?

separation of macromolecules based on size and charge -migration of charged solutes or particles in an electric field--migrate toward the opposite charge electrode

What is a common applications for nephelometry?

serology; -antigen/antibody reactions

What is a blank in spectrophotometry? what might the solvent or cuvette do? what should readout be set to?

solvent without analyte; -most light is transmitted since there should be no particles absorbing light -small amount is absorbed by solvent and cuvette -the readout is set at 100% -is going to have no serum sample

What is the first step in automation? when can it be skipped?

specimen preparation and identification -specimen preparation: can be automated by robotics, can be skipped if whole blood is used for analysis and plasma separator tube can be used and primary tube sampling performed with heparin plasma -specimen identification: bar code label affixed to primary collection tube

Describe the measurement phase - what are 6 systems of measurement? which is the most commonly used?

systems for measurement but depends on instrument being used -ultraviolet, fluorescent, and flame photometry -ion specific electrodes -gamma counters -luminometers -visible and ultraviolet light spectrophotometry (most common) -fluorescence polarization, chemiluminescence, bioluminescence

What is % transmittance? what does 0% T and 100% T mean?

the ratio of the radiant energy transmitted/incident radiant energy of the sample -0%T = all light is absorbed or block -100%T= no light is absorbed (BLANK)

What does spectrophotometry measure?

to determine concentration; instruments measure absorption and emission -measures light transmitted by a solution to determine the concentration of the substance in the solution

What is turbidimetry? (BLOCKED)? measures what light? what instrument is used?

used to determine the concentration of particulate in a sample -measures the amount of light blocked by a suspension of particles (reduction of light that is transmitted) -uses a spectrophotometer

What is chromatography? what are the 4 basic components?

used to separate complex mixtures based on physical interactions between the compounds and the stationary phase; -basic components: 1. mobile phase: vehicle of sample that carries mixture through column (gas or liquid) 2. stationary phase: when mobile phase slows down column (solid or liquid) 3. column: what holds the stationary phase in 4. eluate: the separated components in the end

What is gas chromatography? what is the stationary phase is gas if gas-solid? what is the stationary phase if gas-liquid? what is the mobile phase? sample is injected as? what are the 4 components? what is the electrical signal proportional to?

used to separate mixtures of compounds that are volatile or can be made volatile can be: -gas solid: stationary phase--solid -gas liquid: stationary phase--non volatile liquid components: -mobile phase: gas -sample: injected as gas -columns -detectors -electrical signal is proportional to the concentration of the components