My question about gas chromatography sulfur chemiluminsecence detector. I test unknown sample gas by GC-SCD (calibrated ) and the result of *H2S is 279 PPM , *but when I test the same sample with the GC-TCD (calibrated ) the value of *H2S is 2500 PPM . I'd like to inform you that both GCs are calibrated and have very good operation conditions with stable parameters . the question is if the sample gas with higher H2S over detection limits of SCD detector (1000 ppm). why the result it 279 ppm Best regards

1653

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Why potassium dichromate is used in calibration of uv?

2038

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Why sometime potassium ortho phosphate mix with acetone use for sample preparation for hplc

1500

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What is the difference between Assay and Purity?

1603

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why we are using hexane in calibration of number of drop per mL

1792

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Why we have to add 200mg Na2CO3 in preparation of 0.1N sodium thiosulfate solution?

1629

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Why to use propyl paraben in HPLC gradient calibration

7590

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We use Potassium Dichromate solution for the calibration of UV-Visible Spectrophotometer in UV region. My question is to calibrate visible region which solution could be used in photometric accuracy

1965

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what is NIR wave length

1466

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Why perchloric acid used for potentiometric titration

2735

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What is the Formula for coreletion coefficient in plhplc calibration

1880

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How to calculate coreletion coefficient

1764

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Why do we use vaccum in Loss on drying test?

1727

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WHY pKa value is more important than pH value of the mobile phase in HPLC?

1810

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Many times I don't got a caffeine peak in calibration of hplc using guard column ❓

1876

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