Organics analysis of water quality requirements

HPLC analysis is often used for a variety of organic substances, in combination with a mass spectrometer for LC / MS, a very small amount can be analyzed. Concentration of organic matter in ultrapure water will have an impact directly on the background values.
One. Preparation of ultra-pure water is applied to HPLC, LC / MS of the
Ultra-pure water for the preparation of the mobile phase, and the configuration of the standard solution as control, the experiment with ultrapure water resulting organic background value and the generation of noise is increased, so that the analysis result is disturbed. In HPLC (with UV detection) when ultrapure water of different organic content were detected, the results showed that the content of organic matter and the background absorption value has a positive correlation.
Not irradiated with ultraviolet rays using ultrapure water, the background component value and the target overlap can not be correctly analyzed. In this case, using a UV lamp (wavelength 185nm) irradiation to reduce the organic content, places form ion oxidative decomposition of organic matter is present in water, ion-exchange resin may be used in subsequent purification procedures to be removed. Therefore, during the purification process can be significantly reduced by UV organics (TOC) concentration.
     LC / MS is liquid chromatography to separate the sample, then after ion content analysis to determine the quality of a material of high sensitivity of the system, therefore, be used for the organic content of ultrapure water requirements are very stringent. For ultra-pure water using the ultraviolet lamp system, the purified ultrapure water is suitable for HPLC and LC / MS, we have analyzed in this:
After UV irradiation, respectively, ultra-pure water and without UV irradiation of ultra-pure water added four kinds of synthetic fungicides (CDX, SDMX, PMA, NCZ), conduct comparative analysis map. The results show: the use of standard solution after ultraviolet irradiation of ultra-pure water is prepared, the obtained value is stable and low background and do not overlap with the symmetric peak. The use of ultra-pure water without UV irradiation, the analysis results are presented background value is too high, resulting in overlap with the target group, the results can not be analyzed correctly.
 
     The above results show that the use of ultra-pure water system with the ultraviolet lamp of purified ultrapure water, applied to LC / MS trace analysis.
Second, the application of commercially available HPLC Notes
     HPLC using a commercially available reagent grade water (bottle) is not fully applicable to the LC / MS analysis. HPLC bottled water is removed within the ultraviolet absorption range (200nm ---- 400nm) ultrapure water pollutants, whether using a UV detector, fluorescence detector, or a refractive index detector, bottled water for HPLC detection results are relatively good However, if the detection of total organic content (TOC), can still be detected without having a significant number of organic pollutants in the ultraviolet absorption wavelength.
Here, the use of ultra-pure water, respectively (determined by UV light irradiation) using HPLC with a commercially available reagent grade bottled water line LC / MS analysis. The results showed that noise HPLC water is fairly obvious. Therefore, the use of commercially available HPLC water, you must first blank check to confirm that the water quality will interfere with the analysis results.

     The use by the ultraviolet light of ultra-pure water system is still unable to remove the interference, be sure to use reagent purity. In addition, the preparation of reagents through after long-term storage, whether due to evaporation caused by changing the ingredients, or the occurrence of microbial contamination in aqueous solution, these should be aware of. Therefore, the reagent solution is preferably formulated shortly before use. In addition, ultra-pure water usage also affect detection. Therefore, from the water to the correct method of preparation of reagents, etc., must have some understanding of the Citadines machinery.