Mass spectrometer

Abstract

A mass spectrometer and a liquid chromatography system for a mass spectrometer is disclosed. In a peak parking mode of operation solvent from A and B solvent pumps 9, 10 is immediately diverted to waste reducing the backpressure on an analytical column 21 . Analyte of interest is then allowed to be released from the column 21 at a slower rate by passing fluid from a separate pump 1 through the column 21.

1 . A liquid chromatography system comprising: 
 a first column;    a first fluid delivery system for delivering a first fluid to said first column; and    a second fluid delivery system for delivering a second different fluid to said first column;    wherein in a first mode of operation said first fluid delivery system passes said first fluid through said first column at a first flow rate; and    wherein in a second mode of operation said first fluid is substantially diverted away from said first column and said second fluid delivery system passes said second different fluid through said first column at a second different flow rate.    
   
   
       2 . A liquid chromatography system as claimed in  claim 1 , wherein said first column comprises a reverse phase High Performance Liquid Chromatography (HPLC) column.  
   
   
       3 . A liquid chromatography system as claimed in  claim 1 , wherein said first column has an internal diameter selected from the group consisting of: (i) <50 μm; (ii) 50-100 μm; (iii) 100-200 μm; (iv) 200-300 μm; (v) 300-400 μm; (vi) 400-500 μm; (vii) 500-600 μm; (viii) 600-700 μm; (ix) 700-800 μm; (x) 800-900 μμm; (xi) 900-1000 μm; (xii) 1.0-1.5 mm; (xiii) 1.5-2.0 mm; (xiv) 2.0-2.5 mm; (xv) 2.5-3.0 mm; (xvi) 3.0-3.5 mm; (xvii) 3.5-4.0 mm; (xviii) 4.0-4.5 mm; (xix) 4.5-5.0 mm; (xx) 5.0-5.5 mm; (xxi) 5.5-6.0 mm; (xxii) 6.0-6.5 mm; (xxiii) 6.5-7.0 mm; (xxiv) 7.0-7.5 mm; (xxv) 7.5-8.0 mm; (xxvi) 8.0-8.5 mm; (xxvii) 8.5-9.0 mm; (xxviii) 9.0-9.5 mm; (xxix) 9.5-10.0 mm; and (xxx) >10.0 mm.  
   
   
       4 . A liquid chromatography system as claimed in  claim 1 , wherein said first column has a length selected from the group consisting of: (i) <10 mm; (ii) 10-20 mm; (iii) 20-30 mm; (iv) 30-40 mm; (v) 40-50 mm; (vi) 50-60 mm; (vii) 60-70 mm; (viii) 70-80 mm; (ix) 80-90 mm; (x) 90-100 mm; (xi) 100-110 mm; (xii) 110-120 mm; (xiii) 120-130 mm; (xiv) 130-140 mm; (xv) 140-150 mm; (xvi) 150-160 mm; (xvii) 160-170 mm; (xviii) 170-180 mm; (xix) 180-190 mm; (xx) 190-200 mm; (xxi) 200-210 mm; (xxii) 210-220 mm; (xxiii) 220-230 mm; (xxiv) 230-240 mm; (xxv) 240-250 mm; (xxvi) 250-260 mm; (xxvii) 260-270 mm; (xxviii) 270-280 mm; (xxix) 280-290 mm; (xxx) 290-300 mm; and (xxxi) >300 mm.  
   
   
       5 . A liquid chromatography system as claimed in  claim 1 , wherein said first column comprises C 4 , C 8  or C 18  stationary phase.  
   
   
       6 . A liquid chromatography system as claimed in  claim 1 , wherein said first column comprises particles having a size selected from the group consisting of: (i) <1 μm; (ii) 1-2 μm; (iii) 2-3 μm; (iv) 3-4 μm; (v) 4-5 μm; (vi) 5-6 μm; (vii) 6-7 μm; (viii) 7-8 μm; (ix) 8-9 μm; (x) 9-10 μm; (xi) 10-15 μm; (xii) 15-20 μm; (xiii) 20-25 μm; (xiv) 25-30 μm; (xv) 30-35 μm; (xvi) 35-40 μm; (xvii) 40-45 μm; (xviii) 45-50 μm; (xix) >50 μm.  
   
   
       7 . A liquid chromatography system as claimed in  claim 1 , wherein said first column comprises particles having a pore size selected from the group consisting of: (i) <100 angstroms; (ii) 100-200 angstroms; (iii) 200-300 angstroms; (iv) 300-400 angstroms; (v) 400-500 angstroms; (vi) 500-600 angstroms; (vii) 600-700 angstroms; (viii) 700-800 angstroms; (ix) 800-900 angstroms; (x) 900-1000 angstroms; and (xi) >1000 angstroms.  
   
   
       8 . A liquid chromatography system as claimed in  claim 1 , wherein said first fluid delivery system comprises one, two or more than two pumps.  
   
   
       9 . A liquid chromatography system as claimed in  claim 1 , wherein said first fluid delivery system comprises one or more piston pumps, syringe pumps or peristaltic pumps.  
   
   
       10 . A liquid chromatography system as claimed in  claim 1 , wherein said first fluid delivery system includes an aqueous solvent or solution delivery device.  
   
   
       11 . A liquid chromatography system as claimed in  claim 10 , wherein said aqueous solvent or solution delivery device dispenses, in use, an aqueous solvent or solution.  
   
   
       12 . A liquid chromatography system as claimed in  claim 1 , wherein said first fluid delivery system includes an organic solvent delivery device.  
   
   
       13 . A liquid chromatography system as claimed in  claim 12 , wherein said organic solvent delivery device dispenses, in use, an organic solvent.  
   
   
       14 . A liquid chromatography system as claimed in  claim 13 , wherein said organic solvent is selected from the group consisting of: (i) acetonitrile; (ii) methanol; (iii) propanol; (iv) an alcohol; and (v) tetrahydrofuran (THF).  
   
   
       15 . A liquid chromatography system as claimed in  claim 10  and  12 , wherein the flows from said aqueous solvent or solution delivery device and said organic solvent delivery device are mixed, in use, so as to provide an isocratic flow of fluid to said first column.  
   
   
       16 . A liquid chromatography system as claimed in  claim 1 , wherein said second fluid delivery system comprises one, two or more than two pumps.  
   
   
       17 . A liquid chromatography system as claimed in  claim 1 , wherein said second fluid delivery system comprises one or more piston pumps, syringe pumps or peristaltic pumps.  
   
   
       18 . A liquid chromatography system as claimed in  claim 1 , wherein said second fluid delivery system comprises a sample delivery device.  
   
   
       19 . A liquid chromatography system as claimed in  claim 1 , wherein said second fluid delivery system provides, in use, an isocratic flow of fluid to said first column.  
   
   
       20 . A liquid chromatography system as claimed in  claim 1 , wherein said first flow rate is selected from the group consisting of: (i) <10 nl/min; (ii) 10-20 nl/min; (iii) 20-30 nl/min; (iv) 30-40 nl/min; (v) 40-50 nl/min; (vi) 50-60 nl/min; (vii) 60-70 nl/min; (viii) 70-80 nl/min; (ix) 80-90 nl/min; (x) 90-100 nl/min; (xi) 100-200 nl/min; (xii) 200-300 nl/min; (xiii) 300-400 nl/min; (xiv) 400-500 nl/min; (xv) 500-600 nl/min; (xvi) 600-700 nl/min; (xvii) 700-800 nl/min; (xviii) 800-900 nl/min; (xix) 900-1000 nl/min; (xx) 1-100 μl/min; (xxi) 100-200 μl/min; (xxii) 200-300 μl/min; (xxiii) 300-400 μl/min; (xxiv) 400-500 μl/min; (xxv) 500-600 μl/min; (xxvi) 600-700 μl/min; (xxvii) 700-800 μl/min; (xxviii) 800-900 μl/min; (xxix) 900-1000 μl/min; (xxx) 1.0-2.0 ml/min; (xxxi) 2.0-3.0 ml/min; (xxxii) 3.0-4.0 ml/min; (xxxiii) 4.0-5.0 ml/min; (xxxiv) 5.0-6.0 ml/min; (xxxv) 6.0-7.0 ml/min; (xxxvi) 7.0-8.0 ml/min; (xxxvii) 8.0-9.0 ml/min; (xxxviii) 9.0-10.0 ml/min; and (xxxix) >10.0 ml/min.  
   
   
       21 . A liquid chromatography system as claimed in  claim 1 , wherein said second flow rate is selected from the group consisting of: (i) <10 nl/min; (ii) 10-20 nl/min; (iii) 20-30 nl/min; (iv) 30-40 nl/min; (v) 40-50 nl/min; (vi) 50-60 nl/min; (vii) 60-70 nl/min; (viii) 70-80 nl/min; (ix) 80-90 nl/min; (x) 90-100 nl/min; (xi) 100-200 nl/min; (xii) 200-300 nl/min; (xiii) 300-400 nl/min; (xiv) 400-500 nl/min; (xv) 500-600 nl/min; (xvi) 600-700 nl/min; (xvii) 700-800 nl/min; (xviii) 800-900 nl/min; (xix) 900-1000 nl/min; (xx) 1-100 μl/min; (xxi) 100-200 μl/min; (xxii) 200-300 μl/min; (xxiii) 300-400 μl/min; (xxiv) 400-500 μl/min; (xxv) 500-600 μl/min; (xxvi) 600-700 μl/min; (xxvii) 700-800 μl/min; (xxviii) 800-900 μl/min; (xxix) 900-1000 μl/min; (xxx) 1.0-2.0 ml/min; (xxxi) 2.0-3.0 ml/min; (xxxii) 3.0-4.0 ml/min; (xxxiii) 4.0-5.0 ml/min; (xxxiv) 5.0-6.0 ml/min; (xxxv) 6.0-7.0 ml/min; (xxxvi) 7.0-8.0 ml/min; (xxxvii) 8.0-9.0 ml/min; (xxxviii) 9.0-10.0 ml/min; and (xxxix) >10.0 ml/min.  
   
   
       22 . A liquid chromatography system as claimed in  claim 1 , wherein said second flow rate is substantially lower than said first flow rate.  
   
   
       23 . A liquid chromatography system as claimed in  claim 1 , wherein the ratio of said second flow rate to said first flow rate is selected from the group consisting of: (i) <1; (ii) 0.1-1; (iii) 0.01-0.1; (iv) 0.001-0.01; (v) 0.0001-0.001; (vi) 0.00001-0.0001; (vii) 0.000001-0.00001; (viii) 0.0000001-0.000001; (ix) <0.0000001.  
   
   
       24 . A liquid chromatography system as claimed in  claim 1 , wherein in said second mode of operation said second flow rate is non-zero.  
   
   
       25 . A liquid chromatography system as claimed in  claim 1 , wherein said liquid chromatography system switches, in use, from said first mode of operation to said second mode of operation upon determining, analysing, measuring, detecting, predicting or estimating that one or more analytes of interest or one or more components are emerging, eluting or being transmitted from said first column.  
   
   
       26 . A liquid chromatography system as claimed in  claim 1 , wherein said liquid chromatography system switches, in use, from said second mode of operation to said first mode of operation after a predetermined time.  
   
   
       27 . A liquid chromatography system as claimed in claim  26 , wherein said predetermined time is selected from the group consisting of: (i) <1 s; (ii) 1-10 s; (iii) 10-20 s; (iv) 20-30 s; (v) 30-40 s; (vi) 40-50 s; (vii) 50-60 s; (viii) 60-70 s; (ix) 70-80 s; (x) 80-90 s; (xi) 90-100 s; (xii) 100-110 s; (xiii) 110-120 s; (xiv) 120-130 s; (xv) 130-140 s; (xvi) 140-150 s; (xvii) 150-160 s; (xviii) 160-170 s; (xix) 170-180 s; (xx) 180-190 s; (xxi) 190-200 s; (xxii) 200-210 s; (xxiii) 210-220 s; (xxiv) 220-230 s; (xxv) 230-240 s; (xxvi) 240-250 s; (xxvii) 250-260 s; (xxviii) 260-270 s; (xxix) 270-280 s; (xxx) 280-290 s; (xxxi) 290-300 s; and (xxxii) >300 s.  
   
   
       28 . A liquid chromatography system as claimed in  claim 1 , wherein said liquid chromatography system switches, in use, from said first mode of operation to said second mode of operation in a time t 1 , wherein t 1  is selected from the group consisting of: (i) ≦10 s; (ii) ≦9 s; (iii) ≦8 s; (iv) ≦7 s; (v) ≦6 s; (vi) ≦5 s; (vii) ≦4 s; (viii) ≦3 s; (ix) ≦2 s; (x) ≦1 s; (xi) ≦0.75 s; (xii) ≦0.5 s; (xiii) ≦0.25 s; (xiv) ≦0.1 s; and (xv) substantially instantaneously.  
   
   
       29 . A liquid chromatography system as claimed in  claim 1 , wherein in said second mode of operation fluid dispensed from said first fluid delivery system is substantially diverted away from said first column to waste.  
   
   
       30 . A liquid chromatography system as claimed in  claim 1 , wherein in said second mode of operation at least 50%, 60%, 70%, 80%, 90%, 95%, 99% or 99.9% of said first fluid dispensed from said first fluid delivery system is substantially not transmitted to said first column.  
   
   
       31 . A liquid chromatography system as claimed in  claim 1 , wherein in said second mode of operation substantially 100% of the fluid dispensed from said first fluid delivery device is diverted away from said first column or is substantially not transmitted to said first column.  
   
   
       32 . A liquid chromatography system as claimed in  claim 1 , wherein when said liquid chromatography system switches from said first mode of operation to said second mode of operation the column head pressure associated with said first column is substantially reduced or removed in a time t 2 , wherein t 2  is selected from the group consisting of: (i) ≦10 s; (ii) ≦9 s; (iii) ≦8 s; (iv) ≦7 s; (v) ≦6 s; (vi) ≦5 s; (vii) ≦4 s; (viii) ≦3 s; (ix) ≦2 s; (x) ≦1 s; (xi) ≦0.75 s; (xii) ≦0.5 s; (xiii) ≦0.25 s; (xiv) ≦0.1 s; and (xv) substantially instantaneously.  
   
   
       33 . A liquid chromatography system as claimed in  claim 1 , wherein in said first mode of operation fluid dispensed by said first fluid delivery system causes analyte to be passed from a second column to said first column.  
   
   
       34 . A liquid chromatography system as claimed in  claim 1 , wherein in said first mode of operation said first fluid delivery system serves to maintain a substantially constant or regular flow of fluid through said first column.  
   
   
       35 . A liquid chromatography system as claimed in claim  1 , wherein in said first mode of operation said first fluid passes through said first column at a flow rate of x ml/min, and wherein in said second mode of operation said first fluid passes through said first column at a flow rate of y ml/min.  
   
   
       36 . A liquid chromatography system as claimed in  claim 35 , wherein y is selected from the group consisting of: (i) ≦0.2 x; (ii) 0.15-0.20 x; (iii) 0.10-0.15 x; (iv) 0.05-0.10 x; (v) 0.01-0.05 x; (vi) ≦0.01 x; (vii) substantially zero; and (viii) 0.  
   
   
       37 . A liquid chromatography system as claimed in  claim 1 , wherein analyte having a specific mass to charge ratio has in said first mode of operation a peak elution time selected from the group consisting of: (i) <1 s; (ii) 1-2 s; (iii) 2-3 s; (iv) 3-4 s; (v) 4-5 s; (vi) 5-6 s; (vii) 6-7 s; (viii) 7-8 s; (ix) 8-9 s; (x) 9-10 s; (xi) 10-15 s; (xii) 15-20 s; (xiii) 20-25 s; (xiv) 25-30 s; (xv) 30-35 s; (xvi) 35-40 s; (xvii) 40-45 s; (xviii) 45-50 s; and (xix) >50 s.  
   
   
       38 . A liquid chromatography system as claimed in  claim 1 , wherein analyte having a specific mass to charge ratio has in said second mode of operation a peak elution time selected from the group consisting of: (i) <1 s; (ii) 1-10 s; (iii) 10-20 s; (iv) 20-30 s; (v) 30-40 s; (vi) 40-50 s; (vii) 50-60 s; (viii) 60-70 s; (ix) 70-80 s; (x) 80-90 s; (xi) 90-100 s; (xii) 100-110 s; (xiii) 110-120 s; (xiv) 120-130 s; (xv) 130-140 s; (xvi) 140-150 s; (xvii) 150-160 s; (xviii) 160-170 s; (xix) 170-180 s; (xx) 180-190 s; (xxi) 190-200 s; (xxii) 200-210 s; (xxiii) 210-220 s; (xxiv) 220-230 s; (xxv) 230-240 s; (xxvi) 240-250 s; (xxvii) 250-260 s; (xxviii) 260-270 s; (xxix) 270-280 s; (xxx) 280-290 s; (xxxi) 290-300 s; and (xxxii) >300 s.  
   
   
       39 . A liquid chromatography system as claimed in  claim 37  and  38 , wherein said analyte having said specific mass to charge ratio has a mass to charge ratio selected from the group consisting of: (i) <100; (ii) 100-200; (iii) 200-300; (iv) 300-400; (v) 400-500; (vi) 500-600; (vii) 600-700; (viii) 700-800; (ix) 800-900; (x) 900-1000; (xi) 1000-1100; (xii) 1100-1200; (xiii) 1200-1300; (xiv) 1300-1400; (xv) 1400-1500; (xvi) 1500-1600; (xvii) 1600-1700; (xviii) 1700-1800; (xix) 1800-1900; (xx) 1900-2000; and (xxi) >2000.  
   
   
       40 . A liquid chromatography system as claimed in  claim 1 , wherein in a third mode of operation a sample mixture comprising an analyte is dispensed from said second fluid delivery device.  
   
   
       41 . A liquid chromatography system as claimed in  claim 40 , wherein in said third mode of operation said analyte is held on, held by or otherwise retained by or on a second column.  
   
   
       42 . A liquid chromatography system as claimed in  claim 41 , wherein said second column comprises a reverse phase High Performance Liquid Chromatography (HPLC) column.  
   
   
       43 . A liquid chromatography system as claimed in  claim 41 , wherein said second column has an internal diameter selected from the group consisting of: (i) <50 μm; (ii) 50-100 μm; (iii) 100-200 μm; (iv) 200-300 μm; (v) 300-400 μm; (vi) 400-500 μm; (vii) 500-600 μm; (viii) 600-700 μm; (ix) 700-800 μm; (x) 800-900 μm; (xi) 900-1000 μm; (xii) 1.0-1.5 mm; (xiii) 1.5-2.0 mm; (xiv) 2.0-2.5 mm; (xv) 2.5-3.0 mm; (xvi) 3.0-3.5 mm; (xvii) 3.5-4.0 mm; (xviii) 4.0-4.5 mm; (xix) 4.5-5.0 mm; (xx) 5.0-5.5 mm; (xxi) 5.5-6.0 mm; (xxii) 6.0-6.5 mm; (xxiii) 6.5-7.0 mm; (xxiv) 7.0-7.5 mm; (xxv) 7.5-8.0 mm; (xxvi) 8.0-8.5 mm; (xxvii) 8.5-9.0 mm; (xxviii) 9.0-9.5 mm; (xxix) 9.5-10.0 mm; and (xxx) >10.0 mm.  
   
   
       44 . A liquid chromatography system as claimed in  claim 41 , wherein said second column has a length selected from the group consisting of: (i) <10 mm; (ii) 10-20 mm; (iii) 20-30 mm; (iv) 30-40 mm; (v) 40-50 mm; (vi) 50-60 mm; (vii) 60-70 mm; (viii) 70-80 mm; (ix) 80-90 mm; (x) 90-100 mm; (xi) 100-110 mm; (xii) 110-120 mm; (xiii) 120-130 mm; (xiv) 130-140 mm; (xv) 140-150 mm; (xvi) 150-160 mm; (xvii) 160-170 mm; (xviii) 170-180 mm; (xix) 180-190 mm; (xx) 190-200 mm; (xxi) 200-210 mm; (xxii) 210-220 mm; (xxiii) 220-230 mm; (xxiv) 230-240 mm; (xxv) 240-250 mm; (xxvi) 250-260 mm; (xxvii) 260-270 mm; (xxviii) 270-280 mm; (xxix) 280-290 mm; (xxx) 290-300 mm; and (xxxi) >300 mm.  
   
   
       45 . A liquid chromatography system as claimed in  claim 41 , wherein said second column comprises C 4 , C 8  or C 18  stationary phase.  
   
   
       46 . A liquid chromatography system as claimed in  claim 41 , wherein said second column comprises particles having a size selected from the group consisting of: (i) <1 μm; (ii) 1-2 μm; (iii) 2-3 μm; (iv) 3-4 μm; (v) 4-5 μm; (vi) 5-6 μm; (vii) 6-7 μm; (viii) 7-8 μm; (ix) 8-9 μm; (x) 9-10 μm; (xi) 10-15 μm; (xii) 15-20 μm; (xiii) 20-25 μm; (xiv) 25-30 μm; (xv) 30-35 μm; (xvi) 35-40 μm; (xvii) 40-45 μm; (xviii) 45-50 μm; (xix) >50 μm.  
   
   
       47 . A liquid chromatography system as claimed in  claim 41 , wherein said second column comprises particles having a pore size selected from the group consisting of: (i) <100 angstroms; (ii) 100-200 angstroms; (iii) 200-300 angstroms; (iv) 300-400 angstroms; (v) 400-500 angstroms; (vi) 500-600 angstroms; (vii) 600-700 angstroms; (viii) 700-800 angstroms; (ix) 800-900 angstroms; (x) 900-1000 angstroms; and (xi) >1000 angstroms.  
   
   
       48 . A liquid chromatography system as claimed in  claim 41 , wherein in said third mode of operation salts and/or other contaminants are at least partially or substantially removed from a sample mixture and exit said second column.  
   
   
       49 . A liquid chromatography system as claimed in  claim 41 , wherein in said third mode of operation the relative concentration of analyte in a sample mixture is substantially increased whilst being held on, held by or otherwise retained by or on said second column.  
   
   
       50 . A liquid chromatography system as claimed in  claim 41 , wherein said liquid chromatography system switches to said first mode of operation after said third mode of operation.  
   
   
       51 . An analytical instrument comprising a liquid chromatography system as claimed in  claim 1 .  
   
   
       52 . An analytical instrument as claimed in  claim 51 , wherein said analytical instrument is selected from the group consisting of: (i) an ultra-violet (UV) detector; (ii) an ultra-violet (UV) array detector; (iii) an infra-red (IR) detector; (iv) an ion mobility separator; (v) an ion mobility spectrometer; (vi) a visible ultra-violet (UV) detector; (vii) a Nuclear Magnetic Resonance (NMR) detector; (viii) an Electrospray Light Scattering Detector (ELSD); (ix) a further liquid chromatography system (LC-LC); (x) a refractive index (RI) detector; (xi) a visible detector; (xii) a chemiluminescence detector; and (xiii) a fluorescence detector.  
   
   
       53 . A mass spectrometer comprising a liquid chromatography system as claimed in  claim 1 .  
   
   
       54 . A mass spectrometer as claimed in  claim 53 , further comprising an ion source coupled to said first column.  
   
   
       55 . A mass spectrometer as claimed in  claim 54 , wherein said ion source is selected from the group consisting of: (i) an Electrospray (“ESI”) ion source; (ii) an Atmospheric Pressure Chemical Ionisation (“APCI”) ion source; (iii) an Atmospheric Pressure Photo Ionisation (“APPI”) ion source; (iv) a Laser Desorption Ionisation (“LDI”) ion source; (v) an Inductively Coupled Plasma (“ICP”) ion source; (vi) an Electron Impact (“EI”) ion source; (vii) a Chemical Ionisation (“CI”) ion source; (viii) a Field Ionisation (“FI”) ion source; (ix) a Fast Atom Bombardment (“FAB”) ion source; (x) a Liquid Secondary Ion Mass Spectrometry (“LSIMS”) ion source; (xi) an Atmospheric Pressure Ionisation (“API”) ion source; (xii) a Field Desorption (“FD”) ion source; (xiii) a Matrix Assisted Laser Desorption Ionisation (“MALDI”) ion source; (xiv) a Desorption/Ionisation on Silicon (“DIOS”) ion source; (xv) a Desorption Electrospray Ionisation (“DESI”) ion source; and (xvi) a Nickel-63 radioactive ion source.  
   
   
       56 . A mass spectrometer as claimed in  claim 54 , wherein said ion source comprises a continuous ion source.  
   
   
       57 . A mass spectrometer as claimed in  claim 54 , wherein said ion source comprises a pulsed ion source.  
   
   
       58 . An mass spectrometer as claimed in  claim 54 , wherein said liquid chromatography system switches from said first mode of operation to said second mode of operation upon determining that analyte ions of interest are being eluted to or emitted from said ion source.  
   
   
       59 . A mass spectrometer as claimed in  claim 53 , further comprising a mass analyser.  
   
   
       60 . A mass spectrometer as claimed in  claim 59 , wherein said mass analyser is selected from the group consisting of: (i) an orthogonal acceleration Time of Flight mass analyser; (ii) an axial acceleration Time of Flight mass analyser; (iii) a quadrupole mass analyser; (iv) a Penning mass analyser; (v) a Fourier Transform Ion Cyclotron Resonance (“FTICR”) mass analyser; (vi) a 2D or linear quadrupole ion trap; (vii) a Paul or 3D quadrupole ion trap; and (viii) a magnetic sector mass analyser.  
   
   
       61 . A method of liquid chromatography comprising: 
 providing a first column, a first fluid delivery system for delivering a first fluid to said first column and a second fluid delivery system for delivering a second different fluid to said first column;    passing fluid through said first column by means of said first fluid delivery system at a first flow rate; and then    substantially diverting said first fluid away from said first column and passing said second different fluid through said first column by means of said second fluid delivery system at a second different flow rate.    
   
   
       62 . A method of mass spectrometry comprising the method of liquid chromatography as claimed in  claim 61.