Does the presence of hydrogen sulfide in the oil affect its total sulfur content?
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I have encountered a problem recently; after seeking advice from various sources to find a solution, I am turning to this forum for help. When measuring the hydrocarbons in diesel using a hydrogen sulfide detector, the level of hydrogen sulfide was approximately 3 ppm; when the sample was measured with a single-wavelength sulfur analyzer, the value was around 9 ppm. To ensure accuracy, ultraviolet fluorescence analysis was also conducted, yielding a result of about 4 ppm. Both instruments were calibrated using standard samples before analysis, yet the final results differed significantly. I tried hard to find an explanation for this, and consulted the manufacturers of both instruments, but they were unable to account for this phenomenon. However, my hypothesis that the data differences were caused by variations in the amount of sample introduced was rejected by both manufacturers. The manufacturer of the single-wavelength sulfur analyzer claims that the effect of gases on their measurements is negligible, while the manufacturer of the ultraviolet fluorescence sulfur analyzer states that if hydrogen sulfide is present, the results obtained by this instrument should be higher than those of the single-wavelength sulfur analyzer. I am unable to find the reason for this, and therefore I am turning to this forum for advice; I hope experts can help me out.
This post was last edited by sifangok on 2016-11-24 at 23:15. In case of disputes, the ultraviolet fluorescence method shall prevail; if it is within China, SH/T 0689 shall apply
The last edit to this post was made by sifangok on 2016-11-24 at 23:18. As long as both methods are valid, that’s fine; if there are any objections, then the ultraviolet light method is the preferred one
The key issue is not understanding why; no cause can be found. Could it be that hydrogen sulfide adheres to the sample membrane, affecting the sample results?
There’s no need to worry about it – there must be some interference. **If the standard requires ultraviolet light, then use ultraviolet light; if it’s X-ray diffraction that’s required in Europe, then use X-rays. Even with the same instrument, different manufacturers can produce varying results! Aren’t you even more troubled then?
In the case of online single-wavelength X-ray fluorescence analysis, the accuracy of the data is greatly affected by the degree of contamination of the power window film. If it is a laboratory analysis, consider the impact of hydrogen sulfide emission.
It is currently impossible to determine whether hydrogen sulfide is present; after shaking, neither the hydrogen sulfide detector nor the test strips detected any hydrogen sulfide. It’s unclear why the sulfur content decreases after being left for some time. I’m not sure what could interfere.
I had a bad idea: I used the fluorescent sulfur standard samples as actual samples for single-wavelength analysis, choosing those with concentrations of over 10 ppm. There are already deviations in the data obtained from the same instrument, let alone when using different instruments or methods. Even when I use coulombic sulfur analysis, the values remain at the ppm level; it’s normal for there to be some variation. Just use the appropriate method according to the analysis requirements! Here, for levels below 10 ppm, the use of fluorescent sulfur is required.