%-error 10% rule 10th anniversary 15% rule 21 CFR Part 11 30 years 60-Hz noise 300 columns 656 nm abrasion absorbance accuracy ACD/LC Simulator acetate acetate vs phosphate acetic acid acetonitrile acid cleaning acidity in chlorinated solvents ACS-grade active sites adapting separations additives adjustment adsorption aging air air bubbles air leaks alkylsulfonate alpha amine adsorption amines ammonium acetate ammonium bicarbonate ammonium carbonate anticipate failure antioxidants applications notes AQ aqueous pH aqueous phase archives area reproducibility As assay reference ASTM asymmetry asymmetry factor autoprotolysis constant autosamplers average k average k-value avoid extremes avoid water backflushing background noise backpressure backpressure regulator band broadening band migration base-deactivated baseline problems baselines bases basic solutes Basilica Cistern bat-o-gram Beckman best practices bias bibliography bioanalytical biological samples blank blank gradients blockage blocked frit blocked frits blocked needle blocked waste line block heater boiling point bonded phase books brush phase bubbles bubble test buffer characteristics buffer preparation buffer problems buffer removal buffers bugs built-in diagnostics C18 CAD calculation of LLOD calculations calibration calibration curves cam capacitor short capacity factor carbon loading carryover case study cavitation cell cleaning centrifugation ceramic change one thing at a time changing N changing validated methods charged-aerosol detector check the obvious check valve problems check valves chelation chemical cleaning chemical protection Cheminert chemistry problems chiral chiral drug separation chromatogram chromatogram problems chromatographic hygiene Chromatography Forum chromforum.org chromic acid ChromSword citrate cleaning cleaning frits cleanliness cleanup coefficient of determination collect and reinject column care column chemistry column collapse column dimensions column flushing column lifetime column loading Column Match column overload column parameters column performance column plate number column problems column selection column selectivity column switching column temperature column types column volume common design comparing LC conditions compendial methods competing acids complex samples components concentration connections consistent results consultation contamination continuous improvement continuous variables contributions to variability control charts controlling retentoin convenience converting to isocratic; k range corrosion cost cost-benefit critical peak pair crystal ball current draw curve fit curve fitting curve weighting cutting cyano daily flushing damaged piston data analysis data evaluation data loss data quality data rate data systems DDT dead time dead volume deconvolution dedicated columns degassing degassing problems degassing sonication degradant design Desmet detection wavelength detector cell detector lamps detector performance detector problems detectors detector selection dewetting diameter diameter ratio diaphragm dilution dimensions diphenyl amine dirt dirty cell dirty glassware dirty loop dirty water dirty windows discontinuous variables dissolved air distillation divide and conquer documentation rule do it right the first time drift DryLab dwell volume early elution economics EDTA efficiency electrochemical detector electrochemistry electromagnetic interferences electronic filters electronic noise electronic problems electronics electronic signatures rules ELSD embedded polar group embedded polar phase EMI emission enantiomers endcapping energy English vs metric EPG epimer ratio equilibration equilibrium equivalent separation erosion erratum error calculations ESLD estimates estimating error estimating resolution estimating retention estimating t0 ethers ethylparaben evaporate evaporation evaporative light scattering detector excessive retention excess recovery excipient excitation excluded peak expected variation expert systems expiration dates extended runs external loop external standards extinction coefficient extracolumn effects extraction solvent extra frit extra peaks failure patterns Faraday cage favorite topics feedback ferrules filled loop filling voids filter filters filtration final %B fine tuning fingertight fingertight fittings fire fitting problems fittings floppy diskettes flow cell flow rate fluctuating retention fluorescence detection flush flushing flushing behind heads flush solvent forced degradation forcing zero formulation errors free radicals freeze-thaw frictional heating frit frit blockage frit cleaning frit porosity frit removal frit replacement frit selection fronting fundamental resolution equation gas pressure gel filtration gel permeation geminal general LC principles General Valve GFC ghost peaks goals GPC GPV gradient adjustment gradient delay gradient elution gradient flush gradient linearity gradient problems gradient range gradient retention factor gradient scouting run gradient steepnesss gradient tests gradinet linearity guard cartridge guard columns guest guidelines hard disk hardware hardware failure heart-cut heat exchange heat exchanger helium helium sparging HEPA filter herbal products Hewlett-Packard high-pressure mixing high pH historical data history holistic testing HP HPLC-grade hydrocarbons hydrogen bonding hydrogen ion activity hydrophobic-subtraction model hydrophobic interaction hydroxyproline i.d. ICH immersion bath immiscibility impedance imprecision impurities in-line degassing in-line filters independent service independent service engineers indirect detection indirect photometry infusion initial %B initial drift injection injection precision injection problems injection techniques injection valves injection volume injector injector bypass injector design injector flush injector maintenance injector plumbing injector seal injector seal wear inlet frits inner diameter instrument problems instrument use log insufficient retention integrated system integration interchangeability interferences intermediate runs internal loop internal standards internal standard vs. external standard international internet interstitial volume ion chromatography ion exchange ion exclusion ionic conductance ionic samples ionic strength ion pair ion pairing ion suppression IQ iron inclusions irregular compounds isocratic isocratic method isocratic vs. gradient isolation strategy Jordan junction potential junk mail k' vs %B k' vs % organic k* k-range k-values KCl ketones Keystone kinetic plots KISS Kissinger KISS principle k vs Rs labeling Lake Wobegon effect laminar flow lamp failure large molecules late eluters late elution late retention LC-MS LC-MS/MS LC-UV LC to UHPLC leading bubble leading bubble technique leaks length lifetime light-pipe design light-sensitive mobile phase limit of quantification limit of quantitation linearity linear velocity line noise liquid phases literature methods LKB LLOD LLOQ loading locating leaks LOD logbook log k vs. %B log plots loop filling LOQ loss of bonded phase low-pressure filters low-pressure mixing low pH low plate numbers low sensitivity M. Stadalius MacMod maintenance records Make Before Break manual integration manufacturer choice mass balance mass overload mass transfer matching absorbance matrix-based samples matrix components matrix effects MBB measuring noise measuring pH measuring t0 mechanical errors mechanical failure membrane metabolites metals meters methanol method adjustment method development method of standard additions method performance method problems method transfer microbial contamination microbial growth microbiological contamination microbore microbore precautions Milli-Q. stabilizers minimum resolution miscibility missing information mixing mixing problems mobile phase mobile phase expense mobile phase pH mobile phase problems mobile phase recycling module substitution molecular weight monochromator monofunctional bonding MS detection MTBE N naproxen narrow bore nebulize new column test newsletters NISA nitric acid nitric acid flush nitroaromatics noise noise filter noise reduction noise suppression normal phase obstruction obtaining separation OEM service oil oligonucleotides Omnifit on-column concentration on-line on-line mixing open circuit operator's manual optical path OQ organic solvent flush outgassing outlier out of production ovens over curve overfilled vials overlay overload overload; viscosity oxygen packing extrusion parallel chromatography partial coverage partially aqueous solutions particle size particle size effects particulate matter particulates particulate trap passivation passivation recipe peak purity peak ratios peak separation problems peak shape peak size peak spacing peak volume PEEK Peltier peptide sample percent error percent error plot perfect method performance qualification performance testing performance tests permissible changes peroxides perpendicular drop pH pH 9 pH adjustment pH adjustment technique phase collapse pH effects phenyl pH limits pH meter phosphate phosphate contamination photodecomposition photodiode pH probe contamination pH problems pH range pH scale pH selection phthalate piston piston breakage pKa planning plumbing errors plumbing problems polar compounds polymer-based packings polymer buildup polymeric packings polymeric supports polystyrene poor resolution poor retention Poppe plots poppet valve failure pore size pore volume power disturbances power supply PPPPP PQ PQRI database precipitation precision precision problems precut predicting retention changes prediction preditctions preheater premixing preparative chromatography preservatives pressure bypass pressure decay pressure estimates pressure limits pressure problems pressure readout pressure recording pressure selectivity prevention preventive maintenance priming prior planning prevents poor performance probability problem isolation proficiency propagation of error proportioning errors proportioning test proportioning valves protein proteins pulsations pulse damper pulse damping pulses pump design pump maintenance pump problems pumps pump seals pump tests purchase decision pure standards purge purge cycle purging purification purity factor purposeful degradation push-button experts put it back QL quality quality control samples quantitation quick fix r2 radio frequency interference random noise ratio matching RC filter reader comments readers' questions reader survey reagent purity reagent quality reality check rebuilding reciprocating piston recordkeeping records reduced plate height reference cell reference conditions reference electrode references reference standards refractive index regression regular compounds regular replacement regulation related substances remote diagnostics remote servicing removing waste replacement components replumbing reproducibility reservoir maintenance residual error residuals residuals plot resistance-capacitance resolution resolution and %B resolution equation resolution map resources response factors response time retention retention-time drift retention adjustment retention and %B retentionchanges retention changes retention drift retention factor retention is too small retention of air retention prediction retention problems retention reproducibility retention shifts retention time retention time changes retention time variability retention variation reuse reverse flush reverse flushing review Reviewer Guidance RFI Rheodyne RI detectors robustness rotor routine analysis Rs ruby ruggedness testing rule of one rule of three Rule of Two rules for reliability rules of thumb run time rust S/N salt salt precipitation sample sample concentration sample containers sample delivery sample homogeneity sample loop sample mass sample matrix sample needle sample overload sample preparation sample problems sample size sample vials sample volume sampling rate sapphire sapphire pistons saturation scaling methods scatter scavenger cartridge scouting gradients scouting runs scrubber seal failure seal life seals seat SEC secondary retention selectivity selectivity changes selectivity variables sensitivity sensitivity to mobile phase composition septum septum debris series service service contracts service costs setback shaped cam shielding shifting retention times Shimadzu shock shortcuts signal signal-to-noise signal averaging signature chromatograms silanol effects silanols silica silica chemistry silica dissolution sinker frits siphon size exclusion sizing range skin contact slip-free slope slow equilibration smoothing software solvent changeover solvent characteristics solvent choices solvent consumption solvent front solvent handling solvent inlet filter solvent peak solvent problems solvent reservoir solvents solvent selection solvent selectivity sonication SOP spares sparging specific chemical effects specificity spectra spectral matching speed spikes splitters SST stability indication stabilizers stainless steel stainless steel corrosion standard deviation of the response standardization Standard Operating Procedures standards starting starting conditions static charge static electricity stationary phase selectivity step changes step gradient step test stepwise isolation sticktion Stoll storage storage conditions Stranahan and Deming strategy stressed samples strong adsorption strong retention success rate Supelco superstition support surges swage symptoms and causes syringe plunger syringe size systematic isolation system check system configuration system flush system flushing system logbook system problems system qualification system readouts system reference system stability system suitability system suitability test system suitability testing system suitability tests system to system differences t0 t0 changes tailing factor tangent skim target pH TEA TEAP technical support Tefzel temperature temperature control temperature effects temperature gradient temperature limits temperature problems temperature selectivity testing tetrahydrofuran Tf TFA TFA oxidation TGIF the big picture theoretical plates thermal effects thermal paper probe thermostat The Treasury The World is Flat THF Thomas Friedman threshold threshold limit values throughput throw away failed parts throw it away time constant tips titration TLV top 10 list total internal reflectance trace analysis trace metals trace residues tradeoffs training tray trends triangle triethylamine trifluoroacetic acid TRIS troubleshooting strategies tube blockage tube cutting tube diameter tube extension tubing tubing problems tune-up Turkey turnaround type A silica type B silica UHPLC unexpected failure Upchurch UPS user survey using t0 as a diagnostic tool USP USP database USP guidelines USP Tf UV UV absorbance UV curing adhesive UV cutoff UV detectors UV irradiation vacancy chromatography vacuum vacuum degassing validation valley-height estimates valley-to-valley valve valve corrosion valve design valve maintenance valve rotation valve rotor vapor variability variable sensitivity variance variance contributions varying retention Vespel vial inserts vial inversion vials viscosity viscous heating Vm void void filling voids void volume volatile volume changes volume effects volume not time warranty wash-out volume wash behind seals wash cycles wash solvent waste line waste port water water bath water cleanup with SPE water content water jacket water problems water purification water saturation water scrubber water source. water wash wavelength accuracy wavelength selection web weighting what is different where to start WISP write it down y-intercept zero zero dead volume zero intercept zirconium