Shimadzu Corporation

Matsushita Electric Industrial Co., Ltd.

Trio Kabushiki Kaisha

Shiro Mizutani

Kazuo Mukaibatake

Yuta Miyazaki

Tatsumi Sumi

Yukihiko Miyamoto

Atsushi Ogawa

Shuichi Kawana

Wataru Fukui

Tomoyuki Oshiro

Shigenobu Nakano

Hiroshi Sugawara

An ion analyzerincluding: a power feeding circuitin which a power supply connection part, a first electrode connection part, a first resistance element, a second electrode connection part, a second resistance element, and a grounding part are provided in series; a power supply P connected to the power supply connection partand configured to output both a DC positive voltage and a DC negative voltage; a first voltage supply electrodeconnected to the first electrode connection part; and a second voltage supply electrodeconnected to the second electrode connection part. In particular, it can be suitably used as a device for applying a voltage to a push electrodeand a convergence electrodedisposed in an ionization chamberof a mass spectrometer including an ESI source

Ion analyzer

An acceleration voltage generator is configured to cause a power MOSFET to turn on or off to switch a high direct-current voltage, so as to generate a high-voltage pulse for an ejection of ions from an ion ejector. A drive signal is used to cause the power MOSFET to turn on, and further includes a secondary drive signal to recharge a gate capacitance to cause the power MOSFET to stay in an on-state. In a drive signal generator, edge detection circuits generate an edge detection signal based on a start signal; selection circuits generate a primary drive signal by adjusting the edge detection signal in its signal width; and a secondary drive signal generator includes multiple circuit elements such as a semiconductor element, and generates the secondary drive signal.

Time-of-flight mass spectrometer

An analytical device includes: a first acceleration unit including a first acceleration electrode to which a pulse voltage for accelerating ions is applied; a flight tube; a second acceleration unit that is arranged between the first acceleration unit and the flight tube, and includes a second acceleration electrode to which a voltage for accelerating the ions is applied; an ion detector that detects the ions; and a capacitance adjustment unit that causes adjustment of a capacitance between at least one set of electrodes among a plurality of electrodes arranged in the first acceleration unit, the second acceleration unit, and a flight tube.

Analytical device

An acceleration voltage generator () generates a high-voltage pulse to be applied to an electrode in an orthogonal accelerator by turning on/off a high DC voltage generated by a high-voltage power source through MOSFETs () in a switch circuit (). A controller () sends driving pulse signals to the switch circuit () through a primary-side driver section (), transformer () and secondary driver section (). An adjustment circuit () formed by a gate resistor () and gate capacitor () is provided between the secondary-side driver section () and the MOSFET (). The resistance value of the resistor () and the capacitance value of the capacitor () are determined so as to suppress an overshoot of the gate voltage due to the resonance while preventing a decrease in steepness of the waveform in its rising and falling phases.

An acceleration voltage generator generates a high-voltage pulse applied to a push-out electrode, by operating a switch section to turn on and off a high direct-current voltage generated by a high-voltage power supply. A drive pulse signal is supplied from a controller to the switch section through a primary-side drive section, transformer, and secondary-side drive section. A primary-voltage controller receives a measurement result of ambient temperature of the acceleration voltage generator from a temperature sensor, and controls a primary-side power supply to change a primary-side voltage according to the temperature, thereby adjusting the voltage applied between the two ends of a primary winding of the transformer. The adjustment made on the primary-side voltage changes a slope angle of rise of a gate voltage in the MOSFET, and enables a correction to a discrepancy in the timing of the rise/fall of the high-voltage pulse caused by change in ambient temperature.

An acceleration voltage generator () generates a high-voltage pulse to be applied to a push-out electrode (), by operating a switch section () to turn on and off a high direct-current voltage generated by a high-voltage power supply (). A drive pulse signal is supplied from a controller () to the switch section () through a primary-side drive section (), transformer (), and secondary-side drive section (). The measurement period of a repeated measurement is changed according to a target m/z range. A primary-voltage controller () controls a primary-side power supply () to change a primary-side voltage according to the measurement period, thereby adjusting the voltage to be applied between the two ends of a primary winding of the transformer () by the primary-side drive section (). The pulse signal fed to the switch section () overshoots due to LC resonance. Due to this overshoot, the voltage at the point in time where the pulse signal begins to rise varies depending on the measurement period. Such a variation of the voltage at the point in time where the pulse signal begins to rise causes a discrepancy in the timing at which the rising slope crosses the threshold voltage of MOSFET. However, this discrepancy can be corrected by adjusting the primary-side voltage. As a result, high mass accuracy can be achieved irrespective of the measurement period.

A high-voltage power source for applying high voltage to a nozzle of an ESI ion source includes a charge release assistant section including switch circuits and other elements for forcing electric charges accumulated at output terminals to be discharged in a polarity-switching operation, whereby the positive/negative switching of the polarity of the output voltage can be quickly performed. For example, when the voltage applied to the nozzle needs to be changed from Vto V(where Vand Vare positive, and V&#x3e;V), a voltage control section operates a positive voltage generation section and negative voltage generation section so as to temporarily provide a negative output voltage. After a predetermined period of time, the voltage control section operates the positive voltage generation section and negative voltage generation section so as to provide voltage V.

Mass spectrometer with high-voltage power source

The present invention is a mass spectrometer () for sequentially performing a measurement for a plurality of target ions, characterized by a storage section () for holding ion time-of-flight information concerning the time required for each of target ions to fly through each of the sections constituting the mass spectrometer, and a voltage controller () for changing, based on the ion time-of-flight information, the voltage applied to each of those sections to a voltage suited for each target ion, with a time lag corresponding to the difference in the timing of the arrival of the target ion at the section concerned.

Mass spectrometry method and mass spectrometer

An excessive overshoot preventing unit () is connected to a loop in which a command voltage Vf according to a difference between: a voltage obtained by dividing an output voltage Vout as a high voltage; and a control voltage V cont set from the outside is obtained and fed back to each of drive circuits (and) of a positive voltage generating unit () and a negative voltage generating unit (). The excessive overshoot preventing unit () clamps the command voltage Vf at a voltage value according to the control voltage Vcont. An overshoot that occurs in the voltage generating unit (or) at the time of polarity switching mainly depends on a circuit constant, and hence the amount of overshoot is excessive in the case of a low-voltage output even if the amount of overshoot is optimal in the case of a rated output. To deal with this, in this power unit, the overshoot of the command voltage Vf in suppressed by the excessive overshoot preventing unit (), and hence the output voltage can be promptly settled to a target voltage even in the case of a low-voltage output.

High-voltage power unit and mass spectrometer using the power unit

An output terminal of a positive voltage generating circuit and an output terminal of a negative voltage generating circuit are connected in series, and an output terminal of the negative voltage generating circuit is connected to a ground via a resistor. A switching circuit and a series connection circuit of resistors are connected in parallel to each other between the output terminals of the positive voltage generating circuit and the negative voltage generating circuit. The switching circuit is on-off driven by a voltage signal taken from a junction point between the resistors, and the switching circuit is on-off driven by a voltage signal taken from a junction point between the resistors. Accordingly, when the polarity of an output voltage is switched, electric charges accumulated up to that point are discharged through the switching circuit of a voltage OFF-side polarity, so that the voltage quickly falls.

A quadrupole power source which applies a voltage to each electrode (-) of a quadrupole mass filter () receives inputs of an m/z-axis correction coefficient Mcompand a V-voltage correction coefficient Vcompin addition to a power supply controlling voltage Qcont according to the m/z of a target ion. Vcompis a reciprocal of the ratio by which a frequency is changed, while Mcompis the square of the ratio by which the frequency is changed. In a detection gain adjuster section (C), a multiplier () multiplies an output Vdet' of a V-voltage adjusting amplifier () by Vcomp, whereby the radio-frequency voltage produced by a radio-frequency power supply section (A) is maintained at the same level even when the set frequency of a signal generator () is changed in order to tune an LC resonance circuit.

Quadrupole mass spectrometer

As a control parameter given to a direct-current (DC) voltage generator which generates a DC voltage for ion selection, a 'mass-related offset' for allowing an adjustment of the offset for each mass-to-charge ratio is provided in addition to the 'gain' and &#x201c;common offset&#x201d; which respectively determine the gradient and position of a scan line drawn on a stability diagram during a mass-scan operation. In an automatic adjustment operation using a standard sample, under the control of an automatic regulator, the &#x201c;gain&#x201d; and &#x201c;common offset&#x201d; are initially set, after which the &#x201c;mass-related offset&#x201d; for each mass-to-charge ratio is determined so that the mass-resolving power will be substantially uniform, and these data are stored in a control data memory. In an analysis of a sample of interest, a quadrupole voltage controller controls the DC voltage generator and a radio-frequency (RF) voltage generator according to the control parameters read from the memory.

Provided is a quadrupole mass spectrometer including direct-current voltage sources having response characteristics which ensure that the response time of the direct-current voltage will be shorter than the period of time required for an ion having the highest mass-to-charge ratio (m/z) among the ions introduced into a quadrupole mass filter to pass through this filter. Main rod electrodes and pre-rod electrodes are connected to each other via primary differentiation circuits. Thus, in the transient state of the voltage change due to the switching of the mass-to-charge ratio, among the ions entering the quadrupole mass filter, ions having low m/z values can be removed by a pre-electrode unit, and ions having high m/z values can be removed by a main electrode unit. Accordingly, a large amount of ions can be prevented from passing through the filter and entering an ion detector.

A table () for relating an appropriate DC bias voltage to each of a plurality of selectable scan speeds is stored beforehand in an auto-tuning data memory section (). In an auto-tuning operation, a controller () determines the DC bias voltage corresponding to each scan speed by referring to the table () and fixes the output of an ion-drawing voltage generator () at that voltage. Subsequently, while changing the voltages applied to relevant sections such as an ion optical system (), the controller () finds voltage conditions under which the detection signal is maximized. The conditions thus found are stored in an auto-tuning result data (). In an analysis of a target sample, a DC bias voltage corresponding to a scan speed specified by an operator is obtained from the DC bias voltage table (), and the optimal conditions for this voltage are obtained from the auto-tuning result data (). Based on these items of information, conditions for the scan measurement are determined. This method prevents the deterioration in detection sensitivity, which will otherwise take place if the scan measurement is performed at a high scan speed.

In conventional mass spectrometers, if ions are converged by a radio-frequency electric field under the condition of relatively high gas pressure, the ions are decelerated and are delayed, or stagnated in an extreme case, to cause a decrease in the detection sensitivity or an appearance of a ghost peak. By contrast, in the mass spectrometer according to the present invention, lens electrodescomprises four plate-shaped electrodesthrough, which are radially arranged around the ion optical axis C at intervals of 90 degrees from each other; the four electrodes placed in the plane being approximately perpendicular to the ion optical axis C form a group, and a plurality of the groups are arranged along the ion optical axis C direction at approximately even intervals. The radio-frequency voltages each applied to each of any pair of electrodes adjacent along the direction of the ion optical axis C have a given amount of phase shift. With this configuration, when ions enter the lens electrode, an ion acceleration effect is exerted in accordance with the amount of phase shift of the adjacent radio-frequency electric fields, and the ions are sequentially accelerated as they travel through the lens electrode. Consequently, a delay or stagnation of the ions can be avoided.

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Kyoto, Japan

Shiro Mizutani