LIFGO: A modular laser-induced fluorescence detection system based on plug-in blocks.

In this work, a laser-induced fluorescence (LIF) detection system built in a modular assembling mode was developed based on commercial LEGO blocks and 3D printed blocks. We designed and fabricated a variety of 3D printed building blocks fixed with optical components, including laser light source, filters, lens, dichroic mirror, photodiode detector, and control circuits. Utilizing the relatively high positioning precision of the plug-in blocks, a modular construction strategy was adopted using the flexible plug-in combination of the blocks to build a highly sensitive laser-induced fluorescence detection system, LIFGO. The LIFGO system has a simple structure which could be constructed by inexperienced users within 3 h. We optimized the structure and tested the performance of the LIFGO system, and its detection limits for sodium fluorescein solution in 100 µm i.d. and 250 µm i.d. capillaries were 7 nM and 0.9 nM, respectively. Based on the LIFGO system, we also built a simple capillary electrophoresis (CE) system and applied it to the analysis of DNA fragments to demonstrate its application possibility in biochemical analysis. The separation of 7 fragments in DL500 DNA markers were completed in 600 s. Because of the features of low cost (less than $100) and easy-to-build construction, we introduced the LIFGO system to the experimental teaching of instrumental analysis for undergraduate students. The modular construction form of the LIF detection system greatly reduces the threshold of instrument construction, which is conducive to the popularization of the LIF detection technique in routine laboratories as well as the reform of experimental teaching mode.

Prolonged hemolysis and methemoglobinemia following organic copper fungicide ingestion.

Acute ingestion of copper sulfate has been reported to cause gastrointestinal injury, hemolysis, methemoglobinemia, hepatorenal failure, shock; or even death. The toxicity of organocopper compounds, however, remains largely unknown. A 40-y-old man attempted suicide by ingesting some 50 ml of Sesamine fungicide. He immediately developed headache, vomiting and abdominal pain, followed by progressive dyspnea, cyanosis, dark urine and diarrhea. Severe methemoglobinemia and hemolysis were documented, and treatment with ascorbic acid and hydration was commenced. He was referred to our service 3 d later for methylene blue treatment. Despite the above treatment, his symptomatology persisted and it was not until 5 d post-ingestion that the implicated fungicide was identified as copper-8-hydroxyquinolate. BAL therapy and plasma exchange were instituted, which decreased his plasma hemoglobin from 1,300 mg/dL to 29.1 mg/dL, and lowered his methemoglobin level from 20.9% to 1.1%. His serum and urine copper concentration dropped from 238 microg/dL to 96 microg/dL and from 112 microg/dL to 16 microg/dL, respectively. He was discharged uneventfully 18 d post-ingestion. Pre-existing glucose-6-phosphate dehydrogenase (G6PD) deficiency as well as copper-induced inhibition of G6PD activity was documented during hospitalization. Organocopper compounds may cause prolonged hemolysis and methemoglobinemia through oxidative stress, especially among patients with G6PD deficiency. Antidotal therapy with methylene blue is not likely to be effective in this setting: treatment with intensive supportive measures and other therapeutic options, such as plasma exchange, should be sought.

Determination of aristolochic acids in medicinal plant and herbal product by liquid chromatography-electrospray-ion trap mass spectrometry.

This paper describes a liquid chromatography-electrospray-ion trap mass spectrometry (LC-ES-ITMS) method for the determination of aristolochic acid I and II (AA-I and AA-II) in medicinal plants and Chinese herbal remedies. A reversed phase C(18) column with gradient elution was utilized. The effects of mobile phase additives, acetic acid and ammonium acetate, on LC separation and ES ionization were investigated. For both AA-I and AA-II, the [M+NH(4)](+) ion was found to be the precursor ion for target MS/MS analysis. The MS/MS product ion, [M+H-44](+), was used for the quantitative measurement of AA-I and AA-II. The linearity was good from 0.03 to 5 mug ml(-1) and good correlation (r(2)=0.999) over the range examined was determined for both AA. The detection limit based on a signal-to-noise ratio of three was 0.012 and 0.015 mug ml(-1) for AA-I and AA-II, respectively. Various Chinese herbal remedies obtained from renal failure patients and medicinal plants were examined by this newly developed method.

High-performance liquid chromatographic determination for aristolochic acid in medicinal plants and slimming products.

A HPLC procedure with a silica gel RP-18 reversed-phase column for the determination of aristolochic acids I, II in medicinal plants and slimming products was developed. The mobile system 0.3% ammonium carbonate solution-acetonitrile (75:25, v/v) with pH 7.5 was the optimal buffer to clearly separate aristolochic acids I, II within 20 min. The recovery of aristolochic acids I, II in medicinal plants and slimming products was better than 90% by extracting with methanol and purifying through a PHP-LH-20 column. The major component was aristolochic acid I in Aristolochia fangchi and the level ranged from 437 to 668 ppm. Aristolochic acid II was the major component for Aristolochia contorta and its range was <1-115 ppm. Twelve out of 16 samples of slimming pills and powders contained aristolochic acids I and/or II. The major component in most slimming products was aristolochic acid II and the level ranged from <1 to 148 ppm. It may indicate that slimming products were not mainly made of A. fangchi.