what is the difference between positive and negative mode in interpreting a esi-ms spectrum?
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In positive ion mode the analyte is sprayed at low pH to encourage positive ion formation. In negative ion mode the analysis is normally carried out well above a molecules isoelectric point to deprotonate the molecule.
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What a low resolution NMR spectrum tells you. Remember: The number of peaks tells you the number of different environments the hydrogen atoms are in. The ratio of the areas under the peaks tells you the ratio of the numbers of hydrogen atoms in each of these environments.
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['When the signs are different the answer is negative.', 'When the signs are the same the answer is positive.']
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Positive or negative Uniaxial birefringence is classified as positive when the extraordinary index of refraction ne is greater than the ordinary index no. Negative birefringence means that Δn = ne − no is less than zero.
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If you follow the disappearance of something, the velocity should be "negative" and hence you need to invert it to get a positive reaction velocity. Only when the reaction rate is positive will you find both Michaelis-Menten parameters to be positive.
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For an endothermic reaction, heat is absorbed (+q) and therefore w is negative. For an exothermic reaction, heat is given off (-q) and w is positive. Negative work means that work is done by the system while postive work means that work is done on the system.
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A nonnegative eigenvalue, λ ≥ 0, is also a singular value, σ = λ. The corresponding vectors are equal to each other, u = v = x. A negative eigenvalue, λ < 0, must reverse its sign to become a singular value, σ = |λ|. One of the corresponding singular vectors is the negative of the other, u = −v = x.
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If you have done this, the difference becomes very obvious: Add forces the polarity of the body to be positive. Subtract causes it to be negative. Assemble will use the polarity of the body when performing the boolean operation. It's mostly useful in advanced features.
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The difference between negative and positive feedback systems is that in negative feedback systems, the response reverses the original stimulus, but in positive feedback systems, the response enhances the original stimulus.
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Physical Meaning of Negative Frequency Remembering that physically, sinusoids are waves, the sign of the frequency represents the direction of wave propagation. Simply put, negative frequencies represent forward traveling waves, while positive frequencies represent backward traveling waves.
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BASIC MASS SPECTROMETRY M stands for mass and Z stands for charge number of ions. ... The number of electrons removed is the charge number (for positive ions). m/z represents mass divided by charge number and the horizontal axis in a mass spectrum is expressed in units of m/z.
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The large, 20,000 µF electrolytic unit shown in the upright position has its positive (+) terminal labeled with a “plus” mark. Ceramic, mylar, plastic film, and air capacitors do not have polarity markings, because those types are nonpolarized (they are not polarity sensitive).
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The farther a negative decimal is from zero, the smaller its value. A positive number is always greater than a negative number. This also holds true for decimals and fractions. The smaller the number the closer it is to zero.
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The negative sign on an exponent means the reciprocal. Think of it this way: just as a positive exponent means repeated multiplication by the base, a negative exponent means repeated division by the base.
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A positive result means that IgG was detected, while a negative result means than no IgG was detected. An equivocal test simply means that the results were unclear. A false-negative result can sometimes occur, most often because testing was performed within the window period.
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['Please be sure to read the results within 5 to 10 minutes.', 'Negative test results will show two lines – one line in the control region (C) and one line in the test region (T).', 'Presumptive positive results will show only one line in the control region (C).']
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The order of a reaction is not necessarily an integer. ... Negative integer: A negative order indicates that the concentration of that species INVERSELY affects the rate of a reaction. Positive integer: A positive order indicates that the concentration of that species DIRECTLY affects the rate of a reaction.