X – Nucleus 定標法

X - Nucleus calibration method 

    "The experiments involving heteronuclear spectra may not necessarily have inherent standards for calibration. Therefore, it is necessary to deduce its chemical shift through experiments involving hydrogen. The calculation formula is:

SR(X) = [BF(H) + SR(H)] * gX / gH - BF(X)

Where SR represents the spectrometer reference, BF(H) refers to the basic frequency of hydrogen.   

SR(H) denotes the calibrated reference value of hydrogen. 

The ratio gX over gH represents the frequency measured for nucleus X when hydrogen is at 100 MHz.    

BF(X) is the basic frequency of nucleus X.

   Thus, the SR value for the heteronuclear case is obtained by adding BF(H) to SR value and multiplying   

   it by the ratio gX over gH, then subtracting the basic frequency of nucleus X."

異核實驗並不一定會有內在的標準可以定標，所以需要藉著氫的實驗來推算出它的化學位移。計算公式：

SR(X) = [BF(H) + SR(H)] * gX / gH - BF(X)

    SR 就是定標值 Spectrometer reference，BF(H) 指的是氫的基本頻率。

    SR(H) 指的是氫經過校正以後的定標值。

    gX over gH 是以氫為 100 MHz 的時候，X 核所量測的頻率值。

    BF(X) 是 X 核的基本頻率。

    所以異核的 SR 就是把 BF(H) 加上 SR 值再乘以 gX over gH 這個比值，

    減掉 X 核的基本頻率，就得到了 X 核的 SR 值。

How to obtain the SR (Spectrometer Reference) value for 1H:

1) Measure a 1H spectrum of the sample intended for heteronuclear experiments.

2) Identify the solvent peak and correct its chemical shift.

3) In the command line, type 'sr' and press enter to obtain the SR value for 1H."

如何得到 1H 的 sr：

1）以要作異核實驗的樣品測一張 1H 譜

2）找出溶劑峰，校正其化學位移

3）在指令列鍵入 sr 並執行 enter  即可得 1H 的 sr 值